MSC.Nastran 2005 r2 Release Guide

MSC.Nastran 2005 r2

Release Guide

CorporateMSC.Software Corporation2 MacArthur PlaceSanta Ana, CA 92707 USATelephone: (800) 345-2078Fax: (714) 784-4056

EuropeMSC.Software GmbHAm Moosfeld 1381829 Munich, GermanyTelephone: (49) (89) 43 19 87 0Fax: (49) (89) 43 61 71 6

Asia PacificMSC.Software Japan Ltd.Shinjuku First West 8F23-7 Nishi Shinjuku1-Chome, Shinjyku-KuTokyo 160-0023, JAPANTelephone: (03)-6911-1200Fax: (03)-6911-1201

Worldwide Webwww.mscsoftware.com

Disclaimer

MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice.

The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein.

User Documentation: Copyright 2005 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved.

This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the prior written consent of MSC.Software Corporation is prohibited.

MSC, MSC., MSC.Dytran, MSC.Marc, MSC.Nastran, MSC.Patran, the MSC.Software corporate logo, and Simulating Reality are trademarks or registered trademarks of the MSC.Software Corporation in the United States and/or other countries.

NASTRAN is a registered trademark of NASA. PAMCRASH is a trademark or registered trademark of ESI Group. SAMCEF is a trademark or registered trademark of Samtech SA. LS-DYNA is a trademark or registered trademark of Livermore Software Technology Corporation. ANSYS is a registered trademark of SAS IP, Inc., a wholly owned subsidiary of ANSYS Inc. ABAQUS is a registered trademark of ABAQUS Inc. All other brand names, product names or trademarks belong to their respective owners.

C O N T E N T SMSC.Nastran 2005 r2 Release Guide

MSC.Nastran 2005 r2 Release Guide

Table of ContentsPreface � List of MSC.Nastran Books, x

� Technical Support, xi

� Internet Resources, xiii

1Overview of MSC.Nastran 2005 r2

� Key Highlights for MSC.Nastran 2005 r2, 2❑ SOL 700 Explicit Nonlinear Analysis, 2❑ SOL 600 Implicit Nonlinear Analysis, 2❑ Topology Optimization, 3❑ Elements, 3

� Performance and Processing Improvements, 4❑ Multilevel Distributed Memory Parallel - SOL 103, 4❑ Matrix Domain ACMS, 4❑ Large XDBs, 5❑ Other Processing Enhancements, 5

� Summary of Input Changes and DMAP Updates, 6

� Compatibility and Limitations, 9❑ Results and Output Changes, 9❑ MSC.Nastran 2005 r2 Error List, 10

� Transitioning to MSC.Nastran 2005 r2, 11❑ Documentation Updates, 11❑ Example Problems, 11❑ Cross-Product Support, 12

2Nonlinear Analysis � MSC.Nastran Implicit Nonlinear -- SOL 600, 16

❑ Integration of Linear and Nonlinear Analysis, 16❑ Input, 17❑ Output, 18❑ Solver Capabilities, 19❑ Performance Improvements, 23❑ Known Problems, 24

Table of Contents

❑ Compatibility, 25❑ Improved Contact, 26❑ Defaults, 26❑ Nonsupported Entries, 26❑ Postprocessing, 27

� MSC.Nastran Explicit Nonlinear -- SOL 700 (Pre-Release), 28❑ Introduction, 28❑ Implicit and Explicit Nonlinear Analysis, 29❑ Linear and Nonlinear Analysis Features, 30❑ Input, 30❑ Known Problems, 30❑ Example: Projectile Hitting a Plate with Failure, 33

3Numeric Enhancements

� Multilevel Distributed Memory Parallel (MLDMP), 40❑ Introduction, 40❑ Benefits, 41❑ Input, 42❑ Guidelines, 42❑ MLDMP DMAP Interface, 43

� MDACMS Enhancements, 49❑ Introduction, 49❑ Benefits, 49

� Distributed Memory Parallel MPYAD Module, 52

4Elements � Fastener Element (CFAST), 56

❑ Introduction, 56❑ Benefits, 56❑ Input, 56❑ Output, 65❑ Guidelines and Limitations, 65❑ Examples, 66

� Element Summary Printout (ELSUM), 70❑ Introduction, 70❑ Benefits, 70❑ Input, 70❑ Output, 70❑ Guidelines and Limitations, 71❑ Example, 71

� Spatial Dependent Heat Transfer Coefficient, 75❑ Introduction, 75❑ Input, 75❑ Example, 79

� Two-Variable Heat Transfer Coefficient Tabular Function, 83❑ Introduction, 83❑ Input, 83❑ Theory and Methods, 85❑ Example, 86

� Flux Output Modification for Thermal Analysis, 89❑ Introduction, 89❑ Input, 89❑ Output, 90❑ Theory and Methods, 90❑ Guidelines, 92❑ Example, 93

� Arbitrary Beam Cross Section (Pre-Release), 96❑ Introduction, 96❑ Benefits, 96❑ Inputs and Outputs, 96❑ Guidelines, 97❑ Example, 98

� Other Element Enhancements, 100❑ CHBDY Formulation, 100❑ CHEXA Improper Geometry, 100

5Optimization � Topology Optimization, 102

❑ Introduction, 102❑ Benefits, 102❑ Theory and Methods, 102❑ Input, 103❑ Output, 106❑ Guidelines and Limitations, 108❑ Example 1, 110

� BIGDOT Optimizer, 114❑ Introduction, 114❑ Benefits, 114❑ Input, 114❑ Output, 115❑ Guidelines and Limitations, 115

❑ Example, 115

� Zero Density Material, 116❑ Introduction, 116❑ Benefits, 116

� High’s Method for Eigenvector Sensitivity and Optimization, 117❑ Introduction, 117❑ Benefits, 117❑ Input, 117

6Miscellaneous Enhancements

� Large XDB Support, 120❑ Introduction, 120❑ Input, 120❑ Limitations, 120❑ MSC.ACCESS Application Development, 120

� Enhancements to Modal Damping Processing, 126

� Enhancements to MATMOD Module Option 16, 127❑ Introduction, 127❑ Input, 128❑ Guidelines, 131❑ Example, 131

� DIAG 9 - EQUIVX Diagnostic Message, 134

� EXTSEOUT Case Control Command, 135

� K6ROT Drilling Stiffness Removed for Membrane Only Elements, 136

� New Method to Compute Thermal Expansion for Solid Elements, 137

7DMAP Module Changes

� Summary of DMAP Module Changes from MSC.Nastran 2005 to MSC.Nastran 2005 r2, 140

INDEX MSC.Nastran Release Guide , 155


Preface

� List of MSC.Nastran Books

� Technical Support

� Internet Resources

x

List of MSC.Nastran Books

Below is a list of some of the MSC.Nastran documents. You may order any of these documents from the MSC.Software BooksMart site at www.engineering-e.com.

Installation and Release Guides

❏ Installation and Operations Guide

❏ Release Guide

Reference Books

❏ Quick Reference Guide

❏ DMAP Programmer’s Guide

❏ Reference Manual

User’s Guides

❏ Getting Started

❏ Linear Static Analysis

❏ Basic Dynamic Analysis

❏ Advanced Dynamic Analysis

❏ Design Sensitivity and Optimization

❏ Thermal Analysis

❏ Numerical Methods

❏ Aeroelastic Analysis

❏ Superelement

❏ User Modifiable

❏ Toolkit

❏ Implicit Nonlinear (SOL 600)

xiPreface

Technical SupportFor help with installing or using an MSC.Software product, contact your local technical support services. Our technical support provides the following services:

• Resolution of installation problems• Advice on specific analysis capabilities• Advice on modeling techniques• Resolution of specific analysis problems (e.g., fatal messages)• Verification of code error.

If you have concerns about an analysis, we suggest that you contact us at an early stage.

You can reach technical support services on the web, by telephone, or e-mail:

Web Go to the MSC.Software website at www.mscsoftware.com, and click on Support. Here, you can find a wide variety of support resources including application examples, technical application notes, available training courses, and documentation updates at the MSC.Software Training, Technical Support, and Documentation web page.

Phone and Fax

Email Send a detailed description of the problem to the email address below that corresponds to the product you are using. You should receive an acknowledgement that your message was received, followed by an email from one of our Technical Support Engineers.

United StatesTelephone: (800) 732-7284Fax: (714) 784-4343

Frimley, CamberleySurrey, United KingdomTelephone: (44) (1276) 67 10 00Fax: (44) (1276) 69 11 11

Munich, GermanyTelephone: (49) (89) 43 19 87 0Fax: (49) (89) 43 61 71 6

Tokyo, JapanTelephone: (81) (03) 6911 1200Fax: (81) (03) 6911 1201

Rome, ItalyTelephone: (390) (6) 5 91 64 50Fax: (390) (6) 5 91 25 05

Paris, FranceTelephone: (33) (1) 69 36 69 36Fax: (33) (1) 69 36 45 17

Moscow, RussiaTelephone: (7) (095) 236 6177Fax: (7) (095) 236 9762

Gouda, The NetherlandsTelephone: (31) (18) 2543700Fax: (31) (18) 2543707

Madrid, SpainTelephone: (34) (91) 5560919Fax: (34) (91) 5567280

xii

TrainingThe MSC Institute of Technology is the world's largest global supplier of CAD/CAM/CAE/PDM training products and services for the product design, analysis and manufacturing market. We offer over 100 courses through a global network of education centers. The Institute is uniquely positioned to optimize your investment in design and simulation software tools.

Our industry experienced expert staff is available to customize our course offerings to meet your unique training requirements. For the most effective training, The Institute also offers many of our courses at our customer's facilities.

The MSC Institute of Technology is located at:

2 MacArthur PlaceSanta Ana, CA 92707Phone: (800) 732-7211 Fax: (714) 784-4028

The Institute maintains state-of-the-art classroom facilities and individual computer graphics laboratories at training centers throughout the world. All of our courses emphasize hands-on computer laboratory work to facility skills development.

We specialize in customized training based on our evaluation of your design and simulation processes, which yields courses that are geared to your business.

In addition to traditional instructor-led classes, we also offer video and DVD courses, interactive multimedia training, web-based training, and a specialized instructor's program.

Course Information and Registration. For detailed course descriptions, schedule information, and registration call the Training Specialist at (800) 732-7211 or visit www.mscsoftware.com.

MSC.Patran SupportMSC.Nastran SupportMSC.Nastran for Windows SupportMSC.visualNastran Desktop 2D SupportMSC.visualNastran Desktop 4D SupportMSC.Dytran SupportMSC.Fatigue SupportMSC.Interactive Physics SupportMSC.Marc SupportMSC.Mvision SupportMSC.SuperForge SupportMSC Institute Course Information

[email protected]@[email protected]@mscsoftware.comvndesktop.support@mscsoftware.commscdytran.support@[email protected]@[email protected]@mscsoftware.commscsuperforge.support@[email protected]

xiiiPreface

Internet Resources

MSC.Software (www.mscsoftware.com)

MSC.Software corporate site with information on the latest events, products and services for the CAD/CAE/CAM marketplace.

Simulation Center (simulate.engineering-e.com)

Simulate Online. The Simulation Center provides all your simulation, FEA, and other engineering tools over the Internet.

Engineering-e.com (www.engineering-e.com)

Engineering-e.com is the first virtual marketplace where clients can find engineering expertise, and engineers can find the goods and services they need to do their job

CATIASOURCE (plm.mscsoftware.com)

Your SOURCE for Total Product Lifecycle Management Solutions.

xiv

MSC.Nastran 2004 r3 Release Guidex

CHAPTER

1 Overview of MSC.Nastran 2005 r2

� Key Highlights for MSC.Nastran 2005 r2

� Performance and Processing Improvements

� Summary of Input Changes and DMAP Updates

� Compatibility and Limitations

� Transitioning to MSC.Nastran 2005 r2

2

1.1 Key Highlights for MSC.Nastran 2005 r2MSC.Nastran 2005 r2 introduces several new solution and modeling capabilities that expand the range of problems that can be simulated and solved with MSC.Nastran. The key developments for MSC.Nastran 2005 r2 are summarized in this section. New solution capabilities focus on implicit and explicit nonlinear analysis and topology-based design optimization. These new features are aimed at providing across the board analysis capabilities enabling new and existing models to be analyzed for complex crash and impact conditions not available in the past. The remaining chapters in this guide further expand on these key developments and all other enhancements since MSC.Nastran 2005 r1 (October 2004).

SOL 700 Explicit Nonlinear AnalysisHighlighting nonlinear developments is the introduction of explicit nonlinear analysis --SOL 700. SOL 700 greatly broadens the scope of MSC.Nastran analyses, allowing new and existing models to be analyzed for crash, crush, and drop conditions. This new solution sequence builds on MSC.Nastran’s existing nonlinear analysis solutions and leverages the solver power of MSC.Dytran and LS-DYNA to create a state-of-the art explicit nonlinear capability. This guide describes the Phase 1 implementation of SOL 700 as a pre-release status and sets the stage for future expanded capabilities in this area. The full scale formal introduction of SOL 700 is set for the MSC.Nastran 2005 r3 release.

SOL 600 Implicit Nonlinear AnalysisThe implicit nonlinear (SOL 600) capability, first introduced in MSC.Nastran 2004, sees numerous enhancements highlighted by improved integration between linear and nonlinear solutions. In particular, external superelements generated by previous analyses can now be input into SOL 600 models and conversely SOL 600 can generate superelements for external analyses. SOL 600 can also now export modal data in a MSC.ADAMS MNF file for motion simulation modeling.

MSC.Nastran 2005 r2 introduces an initial thermal contact capability as part of SOL 600. Thermal contact analyses are based upon contact (near, far, and touching) conditions established in SOL 600 and taken into a subsequent SOL 153 or 159 heat transfer analysis.

Additional SOL 600 developments include added solver capability for beam, bar, and shell offsets, improved translations for large models, reduced memory usage, and improved output options.

3CHAPTER 1Overview of MSC.Nastran 2005 r2

Topology OptimizationTopology optimization has been added to the suite of SOL 200 optimization capabilities. In contrast to sizing and shape optimization, topology optimization seeks to find an optimal distribution of material given certain parameters, such as packaging space, loads, and boundary conditions.

Traditional sizing and shape optimization in SOL 200 has been powered by the DOT optimization algorithm which is capable of handling up to a few thousand design variables. To support topology optimization, which can require tens of thousands of design variables, MSC.Nastran 2005 r2 has adopted the BIGDOT optimization algorithm.

The combined power of topology optimization and BIGDOT enables you to truly perform topology optimization on real-world structures.

ElementsMSC.Nastran 2005 r2 unveils a new fastener element --CFAST. The flexible CFAST element, part of the weld family of elements, provides the ability to tie together surface and shell components of differing mesh densities. Properties for the CFAST element, including longitudinal and rotational stiffness, lumped mass, and damping can be specified via the corresponding PFAST entry. The CFAST element expands the capability for modeling weld-type connections from purely rigid properties to varying flexibility.

Another significant advancement in element functionality is the introduction of the Arbitrary Beam Cross Section capability. Introduced as a pre-release feature in MSC.Nastran 2005 r2, the Arbitrary Beam Cross Section feature enables you to define any arbitrary cross-sectional shape for CBAR and CBEAM elements. For existing beam profiles, this feature expands the 1D modeling ability to represent extremely complex shapes. For design tasks, by specifying a set of points that lie on the cross section, defining boundary parameters, and choosing a generic form for the cross- section, you can generate any optimum cross-sectional profile using SOL 200 shape optimization. This feature has particular application to automotive design and the initial pre-release functionality opens the door to further advances in beam design and modeling.

Other upgrades to element functionality include a new element summary capability, extended functionality to model heat transfer coefficients that are spatially dependent or dependent on two variables, and an output request for the heat flow output of structural elements in a thermal analysis.

4

1.2 Performance and Processing ImprovementsImprovements in the area of performance and processing are a major component for MSC.Nastran 2005 r2. These advances open up new analytical abilities for ever increasing model sizes and provide you with more control in the modeling and analysis process. Key developments related to performance and processing are described below.

Multilevel Distributed Memory Parallel - SOL 103The Distributed Memory Parallel (DMP) paradigm enables you to run some Solution Sequences using parallel processing wherein the overall numerical processing task is split into a number of separate instances, each with its own dedicated processor and its own allocation of memory.

MSC.Nastran 2005 r2 extends the power of DMP by introducing a multilevel DMP framework wherein each separate instance can be further split apart amongst groups or clusters of processors rather than just a single processor.

For 2005 r2 the expanded framework is used to implement a frequency segmented Lanczos eigenvalue extraction option in a multilevel fashion with one of the domain decomposition methods (geometric or matrix based) for Normal Modes analysis (SOL 103).

The implementation of Multilevel DMP (MLDMP) is complemented by an enhanced Lanczos modal extraction methodology that significantly improves scalability over previous versions, with efficient handling of very large normal modes analyses over wide frequency ranges, and by enhancements to the matrix-based ACMS domain decomposition (described below).

For MSC.Nastran 2005 r2, MLDMP is available for Normal Modes analysis (SOL 103) through the DOMAINSOLVER Executive Control Statement. However, the expanded framework is available through two new DMAP modules permitting DMAPpers the ability to implement MLDMP in other Solution Sequences.

Matrix Domain ACMSAutomated Component Modal Synthesis (ACMS) domain decomposition has been updated. Matrix Domain ACMS is now the default, replacing the original Geometric Domain ACMS. This enables the initial domain decomposition to take place at the matrix level rather than at the geometry level and leads to significant performance improvements for many types of models.


MSC.Nastran 2005 r2 further enhances Matrix Domain ACMS for both added stability and increased performance. The ability to detect and accommodate large mass degree-of-freedom providing more stability for large mass mode shapes has been added for MSC.Nastran 2005 r2. A series of enhancements to matrix operations, use of distributed memory parallel (DMP) methods, and shared memory parallel (SMP) have helped achieved reductions in processing time of up to 70 percent.

Large XDBsTo accommodate ever increasing model sizes, a multi-key storage method has been implemented to support increased XDB database capacities. The application interface to MSC.Access has also been updated in anticipation of organization changes to the database structure. These changes impact the subroutines used to open and locate keyed objects in the database.

Other Processing EnhancementsThe MATMOD option 16, used to put a matrix into DMIG format in a MATPOOL-type datablock as well as generate DMIG punch output, has a new implementation that eliminates many of the previous limitations and enables you to better control parameters relating to the output data block.

Modal damping processing has been enhanced to provide you with additional information, and warning messages issued for certain conditions that you may encounter.

The MPYAD (matrix multiply-add) module has been modified to perform distributed memory computations.

6

1.3 Summary of Input Changes and DMAP UpdatesChanges to the MSC.Nastran input file to accommodate developments, improvements, and added functionality for MSC.Nastran 2005 r2 are substantial. The following tables categorize these changes according to the section of the Bulk Data file affected and whether the change is related to new input or modifies existing input. The bottom portion of the table shows new DMAP modules and DMAP format changes for MSC.Nastran 2005 r2 which allow for expanded programming, control, and customization.

Input Changes

Section New Modified

Executive Control

DIAGDOMAINSOLVERGEOMCHECKSOL 600,IDSOL 700,ID PRE-RELEASE

Case Control

CMSENERGYENDTIME (SOL 700)HTFLOW

AEROFELSUMDRSPANDSAPRTGPSTRAIN

GPSTRESSMETHODRESVECSTATSUB

Bulk Data MDLPRMMESUPER (SOL 600)MNF600PSOLIDD (SOL 700)

TABLEHTTABLEH1TOPVAR

AEFORCEAEPRESSBCBODY (SOLs 600/700)BCPARA (SOLs 600/700)BCTABLE (SOLs 600/700)CBUSHDEQATNDOPTPRMDRESP2DVCREL1DVCREL2DVMREL1DVMREL2DVPREL1DVPREL2

DYTIMHS (SOL 700)MATS1MATTG (SOL 600)NLAUTO (SOL 600)NLRSFDNLSTRAT (SOL 600)NSML1PARAMARC (SOL 600)PBARLPBUSHPCONVSET1TABDMP1WALL (SOL 700)


Input Changes


Parameters CFDIAGPCFRANDELDYNLOADS*DYNRBE23D*DYPRMSPC*DYRBE3TY*MARCCOMB#MARCHEAT#MARCHOST#MARCLOWE#MARCOFFT#MARCONTF#MARCOPP2#MARCOOCC#MARCPRNG#MARCPRNH#MARCPROG#MARCSAME#MARCSPCD#MARCTEDF#MARCTEDN#MAROFSET#MHEATSHL#

MHEATUNT#MMAT2ANI#MOFFCORE#MOP2TITL#MRCONVER#MRENUELE#MRFINITE#MRFOLOW1#MRFOLOW3#MRFOLOW4#MRGAPUSE#MRMTXKGG#MRNOECHO#MSOLMEM, MBYTE#MSPEEDCW#MSPEEDP4#MSPEEDSE#TCHECKTDMIN

BEAMBEAMARC3D#MARCAUTO#MARCBEAM#MARCBUG#MARCCON2#MARCCON3#MARCCPY#MARCDEF#MARCDILT#MARCDIS2#MARCDIS3#MARCDIS4#MARCDMIG#MARCEKND#MARCEXIT#MARCFILi#MARCIAMN#MARCLUMP#MARCMEM#MARCNOER#MARCONLY#MARCOPT#MARCOTIM#MARCOUTR#MARCPOS#MARCPOST#MARCPRN#MARCPTH#MARCRBAR#MARCRBE2#MARCRBE3#MARCRIGD#

MARCRUN#

MARCSCLR#

MARCSIZ6#MARCSLHT#MARCSOLV#MARCT16#

MARCTABL#MARCTEMP#MARCTIEC#MARCTOL#MARCTVL#MARCUSUB#MARCVERS#MARELSTO#MARMPCHK#MARNOT16#MHOUBOLT#MRBUKMTH#MRDISCMB#MRENUMMT#MRESULTS#MRFOLLOW#MRMAXMEM#MRMTXNAM#MRNOCOR#MRORINTS#MROUTLAY#MRRELNOD#MRSPAWN2#MRT16STP#MRTABLS1#MRTABLS2#

Items with a "#" sign next to them are only available for MSC.Nastran Implicit Nonlinear (SOL 600). Items with a "*" sign next to them are only available for MSC.Nastran Explicit Nonlinear (SOL 700). See the individual parameter for further details.

8

DMAP Updates


DMAP DMPCASEEXPORTLDFBODYLDMDISUTIL

MPPTRANMRGCSTMPNCHGRPPNMKGRP

AELOOPAEMODELAPPENDDOM9DOPR1DSANGKAMGP3GPSTR2GUSTLDWILMP1

MAKMONMATMODMPYADNLSOLVOUTPUT2READROTORSEP1XSEP2XSSG1VIEWP


1.4 Compatibility and LimitationsMSC.Nastran 2005 r2 is backward compatible enabling you to migrate any existing models, Bulk Data files, databases, and results files to this release. The analysis results you obtain with 2005 r2 may vary due to various improvements and are discussed in the section below.

Results and Output ChangesWhen you transition to MSC.Nastran 2005 r2 you will likely see more accurate answers and faster solution times. While all models, BDFs, and databases are upward compatible, the actual numerical answers you obtain rerunning an existing model may change due to improvements made in the following areas:

• Transient loads and enforced motion are calculated in machine precision instead of single precision.

• An improved differentiation scheme has been implemented in transient analysis solution sequences.

• Enforced motion can now also include initial displacement and/or velocity.

• ESE and GPFORCE output may be different if models contain DMIG and/or GENEL entries.

• Contour plots of failure indices may be different when using global plies instead of internal ply IDs.

• Results obtained in analyses where AUTOQSET has been set may differ slightly from those that have manually set QSET/SPOINTS combinations, as the number of generalized coordinates may differ.

• Results for the arbitrary beam cross section may differ for results for the standard MSC.Nastran beam library due to differing element formulations.

• A more stringent Case Control checking procedure may cause jobs that ran previously to stop with a fatal message.

• Residual vector parameters have been tuned to minimize the inclusion of residual vectors due to noise which may have resulted in extraneous residual vectors.

• The CHBDY element mathematical formula has been changed to better control temperatures.

10

MSC.Nastran 2005 r2 Error ListMSC continues to make error reduction a high priority in product development. Efforts to resolve code problems have resulted in the correction of over 250 errors in this release. A complete list of all MSC.Nastran errors is included on the delivery CD. The error list can also be obtained from the “Known Issues” Section of the MSC.Software support website:

http://www.mscsoftware.com/support/prod%5Fsupport/nastran/errorlist/index.cfm


1.5 Transitioning to MSC.Nastran 2005 r2Numerous resources are available to support you in exploring, testing, and adopting the new features for 2005 r2. The top priority has been to provide you with updated documentation that fully describes all new features, functionality, and code changes. The section below summarizes newly released books for 2005 r2. To support the documentation library, there are numerous example problems throughout this guide and available to you for later use.

Many users depend on MSC.Patran or other MSC products to interface with MSC.Nastran 2005 r2. For these users, there is an overview section that addresses any changes to other MSC products that have a direct bearing on MSC.Nastran 2005 r2.

Documentation UpdatesAdditional information on new features, input file changes, and DMAP updates for MSC.Nastran 2005 r2 are reflected in the following updated documentation:

MSC.Nastran 2005 r2 Installation and Operations Guide.

MSC.Nastran Quick Reference Guide - provides complete updates for 2005 r2.

Changes to existing DMAP modules are documented in Chapter 7 of this guide and are intended to supplement the MSC.Nastran 2005 DMAP Programmers' Guide. New DMAP modules will be documented in the MSC.Nastran 2006 DMAP Programmers' Guide.

MSC.Nastran Explicit Nonlinear User’s Guide

MSC.Patran 2005 r2 Release Guide

MSC.Patran 2005 r2 MSC.Nastran Preference Guide

Example ProblemsTo illustrate the new developments and added functionality of MSC.Nastran 2005 r2, several example problems are included in the remaining sections of this guide. After reading over the example problems, if you wish to download these problems to gain first-hand experience with code features and functionality, the data files can be found in the support section of the MSC.Software website:

http://www.mscsoftware.com/support/prod%5Fsupport/nastran/

12

Cross-Product SupportMany of the MSC.Nastran 2005 r2 developments have corresponding development efforts across supporting MSC products. This section provides a short overview of MSC products that support these new features and functionality and directs you to where you can find more information.

MSC.Patran Support

MSC.Patran has introduced several new features that directly reflect MSC.Nastran 2005 r2 developments. Using the MSC.Nastran Preference, you will see the following new features in MSC.Patran 2005 r2:

• Topology Optimization

• Extended Support for SOL 700

• Beam Offsets

• Arbitrary Beam Cross Section Modeling

MSC.Patran 2005 r2 also introduces numerous new features that upgrade support for a broad range of existing MSC.Nastran features and functionality including SOL 600 and SOL 200. For more information, please see the appropriate documentation as noted previously in “Documentation Updates” on page 11.

MSC Solver Product Support

The expansion and power of nonlinear analysis in MSC.Nastran is a direct result of developments that derive from the core MSC solver product line. MSC.Marc and MSC.Dytran provide a solid framework for the new nonlinear analysis capabilities in SOL 600 and SOL 700. For complete updates to these products, please see the following pages on the MSC.Software website.

For MSC.Marc:

http://www.mscsoftware.com/products/products_detail.cfm?PI=1

For MSC.Dytran:



MSC Motion Simulation Product Support

Integration between MSC.Nastran and MSC.Adams continues to be a focus for product development. For MSC.Nastran 2005 r2, modal data from a SOL 600 analysis can be output to a MSC.Adams MNF file enabling you to use the extensive motion simulation tools available in MSC.Adams. For a complete description of these MSC.Adams motion simulation capabilities, please see:


14

MSC.Nastran 2005 Release Guide+

CHAPTER

2 Nonlinear Analysis

� MSC.Nastran Implicit Nonlinear -- SOL 600

� MSC.Nastran Explicit Nonlinear -- SOL 700 (Pre-Release)

16

2.1 MSC.Nastran Implicit Nonlinear -- SOL 600This section describes the various functionality and performance improvements that have been added to SOL 600 between MSC.Nastran 2005 and MSC.Nastran 2005 r2. One of the primary areas of focus has been to establish a bridge of data sharing between the nonlinear capabilities of SOL 600 and other MSC.Nastran linear solution sequences. Also introduced for MSC.Nastran 2005 r2 is the initial ability to simulate thermal contact problems and an added capability to model beam, bar, and shell offsets. Several changes to the output .op2 file and performance upgrades round out the 2005 r2 release of SOL 600.

Integration of Linear and Nonlinear AnalysisThis release introduces new access to the stiffness matrices generated by SOL 600 and in turn enables you to use these to create external superelements or to output modal data to MSC.Adams MNF files.

External Superelements

External superelements are available both for input (generated by previous MSC.Nastran jobs) and output (generated by MSC.Marc using SOL 600). For matrices generated by MSC.Marc, use Bulk Data entry, MDMIOUT to obtain the reduced (or full) stiffness. These matrices can then be used to compute eigenvalues, perform harmonic or random vibration analyses, etc. Note that for MSC.Nastran 2005 r2, the corresponding mass matrix is assumed to be the same as the original and is computed by MSC.Nastran.

For MSC.Nastran-generated matrices, follow the procedure outlined in the MSC.Nastran 2004 Release Guide, Chapter 6 to create the external superelements. In other words, for each creation run, use the same procedures that are used by other MSC.Nastran external superelement creation runs employing the EXTSEOUT Case Control command. For the analysis that combines the external superelements, use the new Bulk Data entry, MESUPER, and include the .asm and .pch files from the superelement creation runs.

Example

An example of the input data for the combination run follows:

SOL 600,101 path=1 stop=1CENDparam,marcbug,0TITLE = 2 SUPERELEMENTS AND THE RESIDUAL -- TEST PROBLEM NO. EXTSE2RSUBTITLE = 8 X 8 MESH OF QUAD4 ELEMENTS; GM-CMS PROJECTparam,mextsee,1

17CHAPTER 2Nonlinear Analysis

SPC = 100LOAD = 1000DISP = ALLK2GG=KAAXM2GG=MAAXBEGIN BULKparam,marcnd99,-1force, 1000, 844, , 0.1, 0., 0., 1.SPC1 100 12346 840 848$2345678 2345678 2345678mesuper 100 extse2a.pchmesuper 200 extse2b.pchinclude 'OUTDIR:extse2a.asm'include 'OUTDIR:extse2b.asm'include 'OUTDIR:extse2a.pch'include 'OUTDIR:extse2b.pch'

ENDDATA

MDMIOUT Entry for MNF Files and Stiffness Matrices

You can output modal data to a MSC.Adams modal neutral file (MNF) using the Bulk Data entry, MDMIOUT. Once this file is read into MSC.Adams you can view and animate modal analysis results. You can find more information on the MSC.Adams family of motion products at:


Input

SOL 600 Statement Default

If SOL 600 with nothing else on the line is entered, the statement will act the same as if the following statement was used:

SOL 600,NLSTATIC OUTR=OP2

IFP (Input File Processing) Checking

Additional checking of all SOL 600 Bulk Data entries is now done during IFP. When one of these entries has erroneous data entered it is more likely that IFP will flag the entry and issue a FATAL ERROR. In most cases, IFP error checking has been enhanced to point to the field and continuation line where the erroneous data occurs.

Changes to the Default Path

When the PATH keyword is omitted on the SOL 600 Executive Control statement, the program will search the following location to find MSC.Marc:

18

MSC_BASE/MSC_VERSD/marc/MSC_ARCHM/marc2005/tools

If MSC_ARCHM does not exist, MSC_ARCH is used instead. The environmental variables MSC_BASE, MSC_VERSD, MSC_ARCH and/or MSC_ARCHM are set by the MSC.Nastran script (see the MSC.Nastran 2005 r2 Installation and Operations Guide for further details). If MSC.Marc is not found on the above path, likely locations near that path are searched. If MSC.Marc is still not found, the job will terminate with an appropriate message and the user must determine the correct location of the MSC.Marc installation, use the PATH=1 keyword (see the MSC.Nastran Quick Reference Guide for further details).

It is possible to use any version of MSC.Marc with MSC.Nastran 2005 r2, but MSC.Marc 2005 r2 is recommended and is the only version to offer all supported capabilities.

Output

.OP2 Changes

Outputs in the OP2 file (as well as f06, xdb and punch) have been enhanced in the following areas:

• MPC forces are now available (requires MSC.Marc 2005 r2 and MSC.Nastran 2005 r2)

• SPC forces are available

• 3D contact results are available

• Displacement, velocity, acceleration results are available

• Cauchy Stress and one type of strain (total, plastic or elastic) are available

• Beam loads are available

• Output in the MSC.Nastran files is controlled the same way as in other MSC.Nastran solution sequences

• Set definitions may be used to limit output for any of the above items

Starting with MSC.Nastran 2005 r2 you must include Case Control requests such as DISP=ALL in order to obtain output in op2, xdb, punch or f06 files. In addition, OUTR requests on the SOL 600 entry must be made (for example OUTR=OP2,F06). The applicable Case Control requests for SOL 600 are DISP, STRESS, STRAIN, SPCFORCE, MPCFORCE, and BOUTPUT. BOUTPUT maps 3D contact to the older 2D Slideline Contact datablock (see “Item Codes” in Chapter 6 of the MSC.Nastran Quick Reference Guide).


A choice of how to define plate and shell stresses and strains is available using Bulk Data parameter, PARAM,MARCGAUS as follows:

The output interval for the t16 file (and thus the OP2 file) is controlled by either the NLPARM Bulk Data entry or the MARCOTIM parameter.

Solver CapabilitiesCore improvements to the solver engine behind SOL 600 has lead to the following new features for MSC.Nastran 2005 r2.

Beam/Bar and Shell Offsets

Prior to MSC.Nastran 2005 r2, bar, beam, and shell offsets could only be modeled by defining extra grid points and connecting those points with RBE2 elements (automatically added by SOL 600). With MSC.Nastran 2005 r2, offsets are available using two alternative methods.

Beam and shell offsets are now available directly from the solver. This eliminates the need to add additional grid points and RBE2 elements, provides more accurate contact simulation of elements with offsets, and more offset options.

Pin flags have been incorporated within the SOL 600 translator. Pin flags are simulated by adding extra grids at the same location and connecting them with MPC’s. Pin flags and offsets cannot both be defined for a particular end of a beam, and if entered will generate an error. The Pin Flag capability is new and considered a pre-release feature.

The original offset method continues to be the default. Accessing offsets directly from the solver is activated by MAROFSET parameter as follows:

MARCGAUS Value OP2 Contents

1 Gauss point stresses are averaged

2 Stresses at Gauss point with Max stress output

5 Stresses at first gauss point output

MAROFSET Integer, Default = 0, ,MSC.Nastran Implicit Nonlinear (SOL 600) onlyDetermines how beam and shell offsets are applied.

20

Implementing the new Pin Flag method is activated as follows:

Simulating Thermal Contact

Heat transfer is not yet part of SOL 600 (this capability is planned for MSC.Nastran 2005 r3). However, thermal contact analysis may be performed by combining the capabilities of MSC.Nastran and MSC.Marc.

To simulate thermal contact:

1. Use SOL 600 to create a MSC.Marc input file including contact surfaces and contact tables.

2. Run MSC.Marc to establish the contact conditions.

0 Extra grids and rigid elements will be created to model the offsets (this was the only capability available until MSC.Nastran 2005 r2.

1 MSC.Marc will automatically handle offsets for beam and shell elements. No extra grids or elements will be created. The offsets will be found in MSC.Marc’s GEOMETRY data.

2 MSC.Marc will automatically handle offsets for beam elements only.

3 MSC.Marc will automatically handle offsets for shell elements only.

MARCPINN Integer, Default = 2, MSC.Nastran Implicit Nonlinear (SOL 600) only

0 If MARCPINN=0, pin flags will be included by created new nodes and appropriate MPC’s by the translator in MSC.Nastran. Pin flags are a beta capability for MSC.Nastran 2005 r2.

1 If MARCPINN is 1, pin flags will be ignored and the translator will continue.

2 If MARCPINN is 2, a severe warning will be issued and MSC.Marc will not run.


3. Return to MSC.Nastran to convert the MSC.Marc contact (near, far, and touching) conditions into equivalent MSC.Nastran entities.

4. Spawn a second MSC.Nastran job to complete the heat transfer analysis using SOL 153 or 159 in MSC.Nastran.

The BCONTACT entry has been revised to account for additional thermal contact items.

Input

Briefly, this type of analysis is accomplished using an input similar to that shown below (additional examples are in the TPL directory with names tc*.dat)

SOL 600,153 path=1CENDANALYSIS = HEATECHO = NONETEMPERATURE(INITIAL) = 2 bcontact=0 SUBTITLE=casea NLPARM = 1 SPC = 1 LOAD = 3 THERMAL(SORT1,PRINT)=ALL FLUX(SORT1,PRINT)=ALLBEGIN BULK$$$$$param*,heatcmd,nast2005t1 <-- MSC development environment onlyPARAM POST 0PARAM AUTOSPC YESPARAM SIGMA 1.714-9NLPARM 1 0 AUTO 5 25 PW NO .001 1.-7PSHELL 1 1 .01CQUAD4 26 1 55 56 64 63 0.CQUAD4 27 1 56 57 65 64 0.......CQUAD4 173 1 226 227 238 237 0.CQUAD4 174 1 227 228 239 238 0.MAT4 1 150. GRID 55 11. 11. 11.GRID 56 11. 10.8571 11.......GRID 238 10.1 11. 10.GRID 239 10. 11. 10.SPC 1 240 1 0.QBDY3 3 1000. 100001QBDY3 3 1000. 100002......

22

QBDY3 3 1000. 100048QBDY3 3 1000. 100049PCONV 1 1001 0 0.CONV 100050 1 0 0 240CONV 100051 1 0 0 240......CONV 100148 1 0 0 240CONV 100149 1 0 0 240bsurf, 101, 75, thru, 174bsurf, 102, 26, thru, 74bcbody, 111, , heat, 101,, heat, 0., 0., 0., 0., 0., 0., 4, , 0., 0., 0.bcbody, 112, , heat, 102,, heat, 0., 0., 0., 0., 0., 0., 4, , 0., 0., 0.bctable, 0, , , 1, slave, 111, 2.06, , , , , , 2.01, , , 500., 0., 0., 0., 0., master, 112$ Initial TemperaturesTEMP 2 240 0.$ Default Initial TemperatureTEMPD 2 0.$ CHBDYG Surface ElementsCHBDYG 100001 AREA4 55 56 64 63CHBDYG 100002 AREA4 56 57 65 64......CHBDYG 100148 AREA4 226 227 238 237CHBDYG 100149 AREA4 227 228 239 238$ Free Convection Heat Transfer CoefficientsMAT4 1001 1000.MAT4 1002 500.$ Scalar PointsSPOINT 240ENDDATA

Files for this analysis are as follows:

jid.dat or jid.bdf (original MSC.Nastran input file)

jid.marc.dat (MSC.Marc input file as translated by MSC.Nastran)


See the update to the “SOL 600,ID” on page 146 of the MSC.Nastran Quick Reference Guide.

DMIG Matrix Output

Corrections have been made to the DMIG matrix output for brake squeal. Brake squeal analysis can now be performed in a single job step or run, rather than the three steps required previously.

CBUSH Entry Warnings

Previous SOL 600 versions ignored the orientation vectors and continuation entry for CBUSH entries without warning messages. MSC.Marc does not support these items. MSC.Nastran 2005 r2 will issue a “Severe Warning” and MSC.Marc will not run if any G0, X1, X2, or X3 CBUSH entries are found. Bulk Data (or rc file) entry, PARAM,MARCBUSH,1 may be used to ignore the orientation vectors.

Performance ImprovementsPerformance improvements for SOL 600 center around two primary areas: contact analysis and large model analyses.

Contact Speed Improvements

Parts of the code have been rewritten to improve the speed of contact analyses involving a large number of multi-point constraint equations (deformable contact) or kinematic constraint equations (rigid contact). This is especially useful for analysis where the total number of nodes in contact is extremely large (a typical example would be two similar plates on top of each other, so that about 50% of all the nodes are in contact). This code improvement is by default active so no special options are required.

jid.marc.nthcnt (MSC.Marc contact description needed by MSC.Nastran)

jid.nast.dat (New MSC.Nastran input file, automatically generated, including thermal contact)

jid.nast.f06 (Final output file)

jid.nast.op2 (Final output file, all standard jid.nast.* output files are also available)

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Multifrontal Solver Memory Reduction

In order to efficiently run large analyses using scratch files, the out-of-core behavior of the multi-frontal sparse solver (MSC.Marc Solver 8) has been updated. These updates include:

1. Adding functionality to use out-of-core assembly of the operator matrix.

2. Utilizing the RAM, which affects both the in-core and out-of-core assembly of the operator matrix, allocated for the solver more efficiently.

3. Rewriting the code applying the multi-point constraint equations such that the amount of scratch file access is tremendously reduced. This is active in solver by default. If needed, it can be switched off by using the parameter feature, 4900.

MATT2 Jobs

Improvements have been made to jobs using temperature-dependent stress-strain curves when MATT2 is specified.

Large Models

Translator speed enhancements have been implemented for certain types of large models. These are not necessary for small or medium sized models but can be requested using the following parameters:

Known Problems

Rigid Element Use

Improvements have been made to SOL 600 to allow more problems with MPC's, RBE2, RBE3, RBAR, and RTRPLT to run to completion. However the improvements are still not capable of running all cases that MSC.Nastran can run (particularly when

Note: For very large analyses, it may be advantageous to set the third entry of the OOC parameter to 1, in which case the solver memory is also used to store some nodal vectors, so that the amount of RAM needed for the analysis is decreased considerably. This is activated using bulk data PARAM,MARCOOCC,2.

PARAM,MSPEEDSE,1 speeds up element processing

PARAM,MSPEEDP4,1 speeds up PLOAD4 processing particularly for solids


Auto M-Set is used). The majority of models with these entries should run without difficulty. Should your analysis exit with an MSC.Marc exit code 2011, have a very low singularity ratio, or experience convergence problems (for example MSC.Marc exit code 3015), there are several potential workarounds that may resolve the issue and allow the problem to run to completion.

1. Add the entry: PARAM,MARMPCHK,3.

This causes the solver to attempt to rearrange these entities if possible.

If still unresolved, then:

2. If RBE3’s are present, change all RBE3s to MPCs using the entry: PARAM,MARCRBE3,0.


3. Change all rigid elements to stiff beams using the entry: PARAM,MARCRIGD,1.


4. Check all rigid elements carefully and run the model using MSC.Nastran SOL 101 and/or 106.

a. Replace contact between the surfaces with MPCs or springs,

b. Determine from the f06 file if any negative or very large terms on the main diagonal of the decomposed stiffness matrix exist,

and

c. Add CELAS or SPC to ground for these degrees of freedom.

If the MSC.Nastran 101 or 106 run is satisfactory but SOL 600 still fails, the only other solution is to remodel the rigid elements and MPC’s.

CompatibilityThe NDDL description for some SOL 600 and SOL 700 Bulk Data entries is not up to date. These entries are intercepted and placed on a special database used by the SOL 600/700 translators. They are not intercepted when MSC.Nastran is run in the db server mode by MSC.Patran, hence the contact data is lost when reading in a data file. Another aspect of the NDDL not being up to date is that the 3D contact Bulk Data entries are only valid for SOL 600 and 700. They must be removed from the input deck for other solution sequences for MSC.Nastran 2005 r2. It is anticipated that this will be corrected in the MSC.Nastran 2006 release.

26

Improved ContactMPC's and rigid elements combined with contact or the same node in more than one contact body can sometimes cause the solver portion of SOL 600 to fail. There is a new optimized contact feature that can frequently help these types of models to run correctly. If MSC.Marc exit 2011 or convergence problems are encountered with such models, you may want to switch to optimized contact.

For MSC.Nastran 2005 r2, optimized contact is not the default for SOL 600.

To invoke optimized contact:

1. Set field 6 of each BCBODY entry with flexible contact to 2.

2. Set field 3 of each "SLAVE" continuation line (the next line after all lines with SLAVE) to 2.

Detailed discussions and an example of optimized contact are provided in Chapter 8 of the MSC.Marc Theory and Information Manual (Volume A of the MSC.Marc documentation) - see text before and after figure 8-4.

DefaultsFor most Bulk Data entries, SOL 600 does not make the distinction between zero and a blank. Thus, if a zero is entered and the default is some other value, the default will normally be used. If you wish to use zero, enter a small number such as 1.0E-12 instead.

Nonsupported EntriesNot all MSC.Nastran SOL 106 or SOL 129 entries are supported by SOL 600. A few of the more commonly used capabilities that are not supported for SOL 600 include:

1. CGAP is only partially supported and its use with SOL 600 is discouraged.

2. The CBUSH CID field is not supported.

3. The new CFAST element is not yet supported.

4. MSC.Nastran superelements are not available yet. SOL 600 may be used to create a superelement and write out a DMIG that may be used in a subsequent MSC.Nastran analysis.

5. Certain Case Control entries such as STATSUB are not available.

6. Inertial Relief is not available.

For a complete list of nonsupported entries, see “SOL 600,ID” on page 146 of the MSC.Nastran Quick Reference Guide.


Postprocessing

For MSC.Nastran 2005 r2, it is still recommended that postprocessing be accom-plished using the t16 file particularly if contact output or multiple type of stress or strain tensor information is desired. MSC.Patran can process all t16 data.

28

2.2 MSC.Nastran Explicit Nonlinear -- SOL 700 (Pre-Release)

IntroductionMSC.Nastran SOL 700 provides an explicit solution procedure to analyze a variety of short duration dynamics problems which include geometric and material non-linearities.

Some of the typical structural applications which are well suited for the SOL 700 explicit analysis are:

• Automotive crash

• Crash/Crush simulations

• Transport container design and drop testing

• Ship Collision

• Projectile penetration

• Jet engine blade containment

• Golf Club simulation

SOL 700 was first introduced as a pre-release solution in MSC.Nastran 2005. The Phase 1 development effort is focused on providing the ability to solve crash and impact problems. Fluids, air bags, seat belts, and occupant safety are not a part of Phase 1, but will be added in subsequent phases.

Using SOL 700 you can create new models or you can use existing MSC.Nastran finite element models for explicit dynamic applications.

The following sections recap the SOL 700 Phase 1 capabilities and provide descriptions of updates and new features made available since MSC.Nastran 2005.

Implicit and Explicit Nonlinear AnalysisSOL 700 works in a manner similar to SOL 600. SOL 700 is powered by a explicit nonlinear solver engine which is linked to MSC.Nastran using an internal translator. MSC.Nastran input data is translated to the solver during the input file processing (IFP). All computations are then made within the solver engine and results for the nonlinear behavior are produced in various file formats.

Explicit procedures have an advantage over implicit solutions if the time step of the implicit solution has to be small.


Implicit methods can be made unconditionally stable regardless of the size of the time step. However, for explicit codes to remain stable, the time step must subdivide the shortest natural period in the mesh. This means that the time step must be less than the time taken for a stress wave to cross the smallest element in the mesh. Typically, explicit time steps are 100 to 1000 times smaller than those used with implicit codes. However, since each iteration does not involve the formulation and decomposition of matrices, explicit techniques are very competitive with implicit methods.

Small time step requirements are not a problem when simulating events that occur quickly, such as impact or crash. However, for longer events such as low frequency dynamics or static analysis, the run time sometimes becomes too large for explicit methods and implicit analysis, such as SOL 109, 129, or 600 should be used.

See the MSC.Nastran Explicit Nonlinear User’s Guide for further theoretical details.

Linear and Nonlinear Analysis FeaturesSOL 700 is an explicit dynamic analysis capability that can perform linear transient analyses (such as SOL 109) as well as nonlinear transient analyses (such as SOL 129).

SOL 700 has available over 25 of the most important and commonly used linear and nonlinear materials. These include plasticity, elastomers, rigid materials, multiple representations of rubber materials, temperature sensitive materials, strain-rate dependent materials, and incompressible to highly compressible rubber/foam.

Contact is described using the same entries as SOL 600; however there is a new entry to easily describe a rigid wall used for car crash simulation. That entry is the WALL entry (see new entry section below).

New entries have also been added to MSC.Nastran to support SOL 700. These entries make it easier to describe crash and impact. Examples are the new TICD entry, that adds a from-thru-by grid ID description so that initial velocity input can be described by one line rather than numerous Grid point lines. This allows an existing input file to be edited and quickly changed to a crash analysis.

In addition, for those familiar with MSC.Dytran, several important MSC.Dytran parameters have been added to MSC.Nastran.

Input

SOL 700 Statement

See the “SOL 700,ID PRE-RELEASE” on page 159 of the MSC.Nastran Quick Reference Guide for the update to this Executive Control statement.

30

Known ProblemsSOL 700 is still designated as a pre-release feature as MSC continues to add key functionality and resolve known issues. Listed below are some known issues which are currently outstanding.

Restart

SOL 700 does not provide a restart capability with this release.

Contact

BCBODY should not be used to model a rigid body, rather model the rigid surface with CQUAD4 elements and use the MATD20 and MATD20M material bulk data entries. For simple flat rigid bodies use the WALL option.

RBE3 and RBE3D Elements

RBE3/RBE3D (LS-DYNA *CONSTRAINED_INTERPOLATION entry) is not working properly and jobs with RBE3 hang on several computer systems. RBE3/RBE3D are therefore converted to MPC for MSC.Nastran 2005 r2.

Distorted Models

When a model distorts badly, the time step for explicit analysis frequently decreases to very small values and eventually can reach zero. LS-DYNA usually flags this as an error and will terminate but the job hangs before control is returned to MSC.Nastran. A fix for this is to enter a starting and minimum time step using PARAM*,DYINISTEP and PARAM*DYMINSTEP. Defaults of 1.0E-6 and 1.0E-9 have been established if these parameters are not entered. If different values are desired, you can enter them (both) in the Bulk Data or in an RC file. RC files do not allow wide-field parameters, therefore if they are to be entered in an RC file the last they must be truncated to 8 characters for example, param,dyiniste,1.0E-4 and param,dyminste,1.0E-8.

Nonsupported Entries

The use of TABLED3 will result in a fatal error, use TABLED1 and TABLED2 instead.

Output

MSC.Nastran 2005 r2 SOL 700 does not create standard MSC.Nastran output files (OP2, XDB, Punch and/or f06. Instead it creates LS-Dyna d3plot and d3thdt files. The former can be visualized using MSC.Patran.


Parallelization

The solver portion of SOL 700 occasionally hangs when using parallel processing when the time step becomes very small or when there is an error in step 2. Monitor your job, and if necessary kill all processes associated with the model.

• Only Windows can be run using PATH=1 on the SOL 700 entry (this uses a file named dynrun.pth to point to the location of dytran-lsdyna)

• All other systems require PATH=3 or no path on the SOL 700 entry. No path is a special case of PATH=3. They both use the run_dytran script. When PATH=3 is specified, a file named sol700.pth is used for inputs to the script. When no path is specified, the script uses defaults that include a single-processor execution. When no path is specified all defaults including the location of MPI/LAM/POE as applicable must be as the run_dytran script expects. When PATH=3 is specified, the location may be specified in the sol700.pth file. The proper version of MPICH is automatically supplied with the 2005 r2 release for Windows and Linux systems.

• We highly recommend the use of PATH=1 for Windows single-processor jobs and PATH=3 for single-processor jobs using other systems. We also recommend the use of PATH=3 for multiprocessor jobs on all supported computer systems.

• If you attempt to run on Linux, MPI-related information is written to /tmp. If you do not have read/write access to /tmp the job will fail. If the mpi-related information is not cleared out of the /tmp directory before the machine is re-booted, new SOL 700 executions after the re-boot think lamboot has already been accomplished and the run_dytran script will not perform the required lamboot necessary to run the job.

• On AIX, POE must be installed where specified in the run_dytran script.

• SGI, HP, Sun, and Alpha appear to run with no anomalies, however mpi must be located where the run_dytran script expects it to be

• For Windows the following MPICH-related items have been discovered during testing.

• Incorrect machine name and IP address

32

Error Description: Easy_connect::WSAETIMEDOUT error, re-attempting easy_connect (hostname) Error: ConnectToMPD (trainer1:8675): easy_connect failed: error 10060. A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. MPIRunLaunchProcess: Connect to trainer1 failed, error 10060 aborting...

Possible Causes: - DNS, the service that maps a hostname to an IP address, is incorrect. You can double check by using ping machinename (machine which is being used in the DMP run)

...No response

• Incorrect User Name/Password

Error Description: Failed to launch process 2: '"\\D10206\sol700\\\\dytran-lsdyna.exe "'LaunchProcess failed, LogonUser failed, Logon failure: unknown user name or bad password.

aborting...

Possible Causes: MPICH requires the following in

Example: Projectile Hitting a Plate with FailureOne typical example of SOL 700 Phase 1 is a projectile hitting a plate at an oblique angle. The initial velocity of the projectile is large enough that over time various elements in the plate fail. Depending on the postprocessor used, if it can account for failed elements, the failed elements are removed from the model.

This model involves contact between the projectile and the plate. SOL 600-style contact is used. It also involves the use of LS-DYNA material MATD024 (elasto-plastic material with arbitrary stress- strain curves and strain-rate dependency). This model with close to 8000 grid points requires about 20 minutes to run on a 2.4 GHz PC.

The following plots show the evolution of the effective stress and damage with time:


34

Portions the MSC.Nastran input file named projtl.dat are shown below.


SOL 700,NLTRAN path=1 stop=1TIME 10000CEND ECHO = NONE DISPLACEMENT(SORT1,print,PLOT) = ALL Stress(SORT1,PLOT) = ALL Strain(SORT1,PLOT) = ALL accel(print,plot)= ALL velocity(print,plot)= ALL echo=both SPC = 2 IC=1 TSTEPNL = 20 BCONTACT = 1 weightcheck=yes pageBEGIN BULKTSTEPNL 20 10 11 1 5 10 + + + + 0 PARAM,DYDTOUT,5PARAM*,DYCONSLSFAC,1.0PARAM,OGEOM,NOPARAM,AUTOSPC,YESPARAM,GRDPNT,0param,dyendtim,1param,dymats1,1param,dyldknd,0$BCTABLE 1 4 SLAVE 3+ YES MASTER 4 $BCBODY 3 3 DEFORM 3 0BCBODY 4 3 DEFORM 4 0$BCPROP 3 2BCPROP 4 1$$$ ========== PROPERTY SETS ========== $$ * projectile *$PSOLID 1 1$$ * plate *$PSOLID 2 2$$$ ========= MATERIAL DEFINITIONS ==========$$$$ -------- Material MAT_PLASTIC_KINE.2 id =2MATD024 1 18.62 1.17 .22 0.0179 0.8

36

$ -------- Material MAT_PLASTIC_KINE.1 id =1MATD024 2 7.896 2.1 .284 0.01 0.8$$ $$ ======== Load Cases ========================$$$ ------- Initial Velocity BC ini ----- $TICD 1 1 1 0.1246 2586 1TICD 1 1 3 -0.03339 2586 1...ENDDATA

All of the previous input data are described in the MSC.Nastran Quick Reference Guide. Note that it was only necessary to add BCONTACT=1 to the Case Control, a few new Bulk Data parameters and a few contact entries to an existing Bulk Data file that would be used in a MSC.Nastran SOL 101, 106, 109 or 129 analysis.

Example: Pickup Truck Crash Test

The following example involves crash testing of a pickup truck against a rigid wall. It is a typical example of what can be done using a full car or truck model, developed originally for NVH analysis and subsequently used in a SOL 700 crash simulation.


Where Can I Find More Information:

MSC.Nastran Explicit Nonlinear Analysis, SOL 700, is documented in the following manuals and guides:

• MSC.Nastran Quick Reference Guide

• MSC.Nastran Explicit Nonlinear User’s Guide

• MSC.Patran User’s Guide

• MSC.Patran – MSC.Nastran and MSC.Dytran Preference Guides

38


CHAPTER

3 Numeric Enhancements

� Multilevel Distributed Memory Parallel (MLDMP)

� MDACMS Enhancements

� Distributed Memory Parallel MPYAD Module

40

3.1 Multilevel Distributed Memory Parallel (MLDMP)

IntroductionSeveral of MSC.Nastran’s Solution Sequences (101, 103, 108, 111, 112, and 200) have available to them a framework for domain decomposition and parallel processing. This framework in essence can split up the overall numerical processing task into multiple independent subtasks (domain decomposition) and then harness the power of multiple processors operating in parallel (parallel processing). Dependent on the Solution Sequence, a number of domain decomposition methods are available to define how the numerical processing is split apart or segmented. Once segmented, each separate processing task is analogous to a separate instance of running MSC.Nastran and can either be using Shared Memory Parallel (SMP), where each instance is sharing common memory, or Distributed Memory Parallel (DMP) where each instance is allocated its own memory.

The Multilevel Distributed Memory Parallel (MLDMP) extends the framework to further split up each instance amongst a group or cluster of processors.

For 2005 r2 the nested or multilevel DMP framework is used to implement a new hierarchic Lanczos method. The new method takes advantage of the frequency-segmented Lanczos option in a nested or multilevel fashion with one of the domain decomposition methods (either grid-based or matrix-based). The frequency-segmented Lanczos option for normal modes divides the given frequency range into a user-specified number of segments, and then performs an eigenvalue analysis on each segment in parallel, where a separate processor is assigned to each segment. With the hierarchic Lanczos method, each segment is assigned to a group or cluster of processors, and each cluster performs the eigenvalue analysis in parallel, using a domain decomposition method.

The hierarchic Lanczos method is available only in Solution 103. However, the new framework is available through DMAP (the Direct Matrix Abstraction Program), permitting DMAPpers the ability to use DMAP alters and customizations to implement the framework for other Solution Sequences as they see appropriate.

Complementary Enhancements

The performance of the frequency-segmented Lanczos option as well as the hierarchic Lanczos method has been enhanced by a new load balancing algorithm for MSC.Nastran 2005 r2. The load balancing algorithm tries to determine frequency segment boundaries which result in segments containing approximately the same number of eigenvalues. If the load balancing algorithm fails, the default heuristically-determined segment boundaries are used.

41CHAPTER 3Numeric Enhancements

The performance of the matrix-based domain decomposition option has also been enhanced by an improved implementation of the reordering scheme used by the sparse decomposition. In previous releases, the matrix-based domain decomposition option could be much slower than the grid-based option, and could require significantly more disk space. With the new enhancement, the elapsed time and disk space requirements of the matrix-based option and the grid-base option are roughly the same.

BenefitsEmploying nested groups or clusters of processors with MLDMP can lead to substantial improvements in run times and the increased capacities to handle ever-increasing model sizes.

The chart below shows an example of the improvements that can be gained in both processing time and elapsed time using additional processors with MLDMP. In this case, there was a 82% reduction in CPU time.

# of Processors

Time(secs)

42

InputAs with all MSC.Nastran DMP methods, the overall total number of processors must be specified on the command line using the dmparallel keyword. The keyword may be abbreviated as dmp.

The simplest way to specify the number of frequency segments is the nclust command-line keyword. The nclust keyword is a synonym for system cell 421. The number of domains used in the domain decomposition method on each frequency segment is determined by the quotient dmp/nclust.

Alternatively, it is possible to specify the number of domains for each frequency segment using the clustsz keyword. The clustsz keyword is a synonym for system cell 422. In this case, the number of frequency segments is determined by the quotient dmp/clustsz.

Either the value of nclust or clustsz may be specified in the input file as an option to the DOMAINSOLVER statement in the Executive Control Section:

domainsolver modes ( nclust=4 )

domainsolver modes ( clustsz=2 )

If both keywords, nclust and clustsz, are specified either on the command line or in the Executive Control Section, then their product should equal the value specified by the dmp command-line keyword. If the product does not equal the dmp value, the clustsz keyword is ignored.

For MSC.Nastran 2005 r2, the default domain decomposition option in Lanczos is grid based. The matrix-based option may be specified by setting system cell 364 to the number of domains, or by setting partopt=dof as an option in the DOMAINSOLVER entry of the Executive Control section.

GuidelinesThe upper limit of the frequency range must be specified either on the F2 field of the EIGRL Bulk Data entry, or on the V2 field of the EIGR Bulk Data entry.

MSC.Nastran will not scale well beyond the number of available I/O channels. For example, when running with dmp=16, one would see better scaling if the 16 processors were on separate nodes of a cluster, each node with its own local scratch disk(s), rather than on a single node with 16 processors and only one or two scratch disks.


A model dominated by shell elements may scale well using 4, 8, and perhaps 16 domains, while a model dominated by solid elements may not scale well beyond 2 or 4 domains.

The grid-based domain decomposition option generally has better performance than the matrix-based option. However, for fluid-structure problems, the grid-based option is not supported, and the matrix-based option should be used.

The partitioning algorithm for the domain decomposition methods may fail if the number of domains is not a power of 2.

MLDMP DMAP InterfaceMultilevel DMP is only available for SOL 103 in the standard delivery of MSC.Nastran 2005 r2. However, the framework is accessible through two new DMAP modules, PNMKGRP and PNCHGRP, and several relevant system calls. Through the DMAP interface you can prototype DMP in other solution sequences and implement nested parallelism.

Prior to MSC.Nastran 2005 r2

DMAPpers in the past had some ability to implement DMP solutions. The number of processors, and the processor ID were available through system cells 231 and 265, respectively. Data blocks could be exchanged and manipulated via the DISUTIL options. So, it was possible, for example, to perform parameter studies employing these options.

MSC.Nastran and DMAP sometimes check for DMP processing by testing the value of SYS231. If you wanted to implement DMP, you would have to find all DMP branches and somehow alter the value of SYS231 in those places to make sure the job would take the desired path when run in DMP. Additionally, if any modules had DMP capabilities (such as, READ, DCMP,MPYAD), the value of SYS231 would need to be set to 1 there as well.

Prior to MSC.Nastran 2005 r2, nested parallelism was not possible. You would have had to assign each group of 4 processors to the main computational task and then have it execute in parallel. Unfortunately, this approach would not work without major code changes because the DMP paradigm used in MSC.Nastran is the “master-slave” model, and the master processor must have Processor ID 1. You could not simply alter the processor ID's using DMAP, because there is no way to communicate the altered processor ID's to the underlying message passing (MPI) routines without significant code changes.

44

Multilevel Parallelism in MSC.Nastran 2005 r2

The MPI standard does provide for nested parallelism through the concept of MPI groups. A “group” in MPI is a subset of processors assigned its own communication infrastructure. A group has its own local, private values for the number of processors in the group, the processor ID's, a unique “communicator.” A processor may belong to more than one group, but at any given time, a processor may only participate in one of those groups, which we will call the “active” group. The communicator ensures that messages are only passed among processors which belong to the active group.

The new MLDMP framework provides DMAP access to the MPI group infrastructure through two new modules: PNMKGRP and PNCHGRP. The MLDMP framework:

• Simplifies running parameter tests or parallelizing simple DMAP loops.

• Enables nested parallelism in DMAP.

• Permits different parallel contexts within the same run.

A particular DMAP may offer an opportunity for parallel computations, but among the computations which can be run in parallel, some may require more processors than others. The MLDMP framework permits the creation of groups of different sizes, and the group of the appropriate size could be assigned to each task. Furthermore, nested parallelism may be useful at only one point in the DMAP, so it is possible with MLDMP to turn the nested parallelism ON and OFF.

The MLDMP DMAP interface consists of two modules, PNMKGRP and PNCHGRP, described below. Several pertinent system cells that help you write DMP DMAPS are listed below.

Relevant System Cells

Cell Number Keyword Description

197 Numseg Number of segments in frequency segmented Lanczos.

231 dmparallel Number of processors.

265 Processor id.

294 Debug output for domain decomposition and for MLDMP modules.

349 Number of geometric domains used in domain decomposition.


364 Number of matrix domains used in domain decomposition.

421 nclust Number of segments for hierarchic Lanczos.

422 clustsz Number of domains for hierarchic Lanczos.

Cell Number Keyword Description

46

Format:

Input Data Blocks:

None.

Output Blocks:

None.

Parameters:

Remarks:

1. The parent group set identified by the first parameter must be the ’active’ group when the child group set is created. The default active group is the ’WORLD’ group. A child group is made active using the PNCHGRP module.

PNMKGRP For multi-level DMP; creates a set consisting of one or more (sub)groups.

PNMKGRP //PLABEL/NSUBGP/GRPSIZ/PIDINI/INCPID/INCGRP/GPLABEL $

PLABEL Input-character-default=’WORLD’. The label associated with the parent group set.

NSUBGP Input-integer-default=1. The number of subgroups to create in the new set.

GRPSZ Input-integer-default=1. The number of processors in each subgroup.

PIDINI Input-integer-default=1. The first processor id of the parent group which will be included in the first new subgroup.

INCPID Input-integer-default=1. The stride from one processor identification number of the parent group which is included in a given subgroup, to the next processor identification number of the parent group which is included in the same group.

INCGRP Input-integer-default=1. The stride from the first processor identification number of the parent group that is included in a given subgroup, to the processor identification number of the parent group that corresponds to the first processor identification number that is included in the next subgroup.

GPLABEL Input-character-no default. The label associated with the new set of subgroups.


2. If there are more than one groups (NSUBGP > 1), then all the groups must have the same number of processors.

Examples:

1. From the world group of 20 processors, create a set of 5 subgroups with processor identification numbers {1,2,3,4}, {5,6,7,8}, {9,10,11,12}, {13,14,15,16}, {17,18,19,20}:

2. From the world group of 20 processors, create a set of 5 subgroups with processor identification numbers {1,6,11,16}, {2,7,12,17}, {3,8,13,18}, {4,9,14,19}, {5,10,15,20}:

3. From the world group of 20 processors, create a set 1 subgroup with processor identification numbers {1,5,9,13,17}:

PNMKGRP //’world’/5/4/1/1/4/’mygroup1’

PNMKGRP //’world’/5/4/1/5/1/’mygroup2’

PNMKGRP //’world’/1/5/1/4//’masters1’

48

For multi-level DMP, changes the active group set from a parent to a child group or from a child to a parent group.

Format:

Input Data Blocks:

None.

Output Blocks:

None.

Parameters:

Remarks:

1. If a processor does not belong to any of the groups associated with TOLABEL then IBELONG will be zero and PNCHGRP will not change the parallel processing environment for that processor. If a processor does belong to a group associated with TOLABEL, then IBELONG will be one.

2. PNCHGRP can only change groups from a parent to a child or from child to a parent.

3. PNCHGRP redefines system cell 231 (NPROCS) and system cell 265 (the processor ID) to be their local values within the new group.

PNCHGRP

PNCHGRP //FROMLABL/TOLABEL/IBELONG $

FROMLABL Input-character-no default. The label associated with the present group set.

TOLABEL Input-character-no default. The label associated with the new group set.

IBELONG Output-integer-no default. A zero value of this parameter indicates that the processor does not belong to any of the subgroups associated with the TOLABEL label.


3.2 MDACMS Enhancements

IntroductionThe Matrix Domain ACMS capability (MDACMS) was originally released in MSC.Nastran 2004 r3 (May 2004). This capability was enhanced and extended in the general MSC.Nastran 2005 release in September 2004. With the release of MSC.Nastran 2005 r2, MDACMS is now the default ACMS method, replacing the original Geometric Domain ACMS (GDACMS) method originally introduced in MSC.Nastran 2001.

Several upgrades have been made to the Matrix Domain ACMS feature to overcome previous problems with handling large masses.

BenefitsEnhancements to MDACMS can be categorized as improvements to robustness and improvements to performance. These changes are described below.

Robustness

One of the chief causes of error terminations or inaccurate results in an MDACMS analysis is a failure to compute accurate component modes from one or more automatically generated matrix domain components. This can happen due to the presence of massless mechanisms or large masses, for example. For MSC.Nastran 2005 r1, MDACMS terminates the analysis if a component eigensolution fails for any reason, and indicates a corrective action. In most cases, the problem is simply resolved by increasing the Lanczos MAXSET parameter on the EIGR or EIGRL Bulk Data entries. If this does not resolve the problem, it may be necessary to examine the model for modeling errors using a non-ACMS massless mechanism solution.

For MSC.Nastran 2005 r2, preventative measures have been taken to eliminate ACMS errors related to handling large masses. These include the following:

• Automatic detection of and special solution for large mass degrees of freedom.

• Increased and variable Lanczos MAXSET inside MDACMS.

The large mass method of enforced motion has been superseded by the SPCD method, which is the recommended method. In order to accommodate legacy models, a procedure is implemented in MSC.Nastran 2005 r2 to detect and handle large masses so that the MDACMS solution can solve for all of the large masses. This capability, in

50

combination with a dynamic Lanczos MAXSET capability, provides additional stability to the MDACMS solution. MDACMS automatically adjusts the Lanczos MAXSET, where appropriate, to solve for the large mass mode shapes.

Performance

Enhancements implemented in MDACMS for MSC.Nastran 2005 r2 generally result in a 20 to 25 percent performance improvement. In addition, high frequency range analyses, which require a large modal space of 10,000 modes, for example, should improve 70 percent or more.

MDACMS Improvements

Specific improvements to MDACMS include:

• Enhancements to matrix multiply-add operations employed in matrix reduction cases specific to MDACMS.

• Enhancements to matrix forward-backward substitution (FBS) operations employed in matrix reduction cases specific to MDACMS.

• Increased Lanczos MAXSET for the MDACMS system modes eigensolution.

• Removal of inefficiencies for the special Inverse Lanczos MDACMS system modes solution, related to eigenvector normalization.

• Implementation in an enhanced incore block-form Inverse Lanczos eigensolution for MDACMS system modes.

• Implementation of Frequency Domain parallel Lanczos for MDACMS system modes (DMP only).

• Improved load balance for Frequency Domain parallel Lanczos for MDACMS system modes (DMP only).

• DMP parallel MPYAD module.

• Shared memory parallel (SMP) implementation of vendor supplied math kernels.

• Output Transformation Matrix (MDOTM) method of eigenvector recovery.

Below is an example that demonstrates typical speedup for large frequency range cases. Note that SMP is a MSC.Nastran 2005 r2 feature for MDACMS.


52

3.3 Distributed Memory Parallel MPYAD ModuleThe MPYAD module (matrix multiply-add) now performs distributed memory computations. Two distributed memory parallel (DMP) methods have been implemented.

In DMP method 1, the [A] matrix is distributed among DMP processes. The [B] matrix is distributed in parallel method 2. Partial products are computed in each DMP process, and the results are then gathered by the master DMP process.

The new format for the DMP enabled MPYAD module is shown below. Three new parameters, DODMP, SENDIN, SENDOUT, control the DMP option.

Perform the multiplication of two matrices and optionally, the addition of a third matrix to the product.

Format:

Input Data Blocks:

Output Data Block:

MPYAD Matrix multiply and add

MPYAD A,B,C/X/T/SIGNAB/SIGNC/PREC/FORM $

A Left-hand matrix in the matrix product.

B Right-hand matrix in the matrix product.

C Matrix to be added to the product.

X Matrix product.

X[ ] A[ ]T± B[ ] C[ ]±=


Parameters:

T Integer-input-default = 0. Transpose flag.

T = 1, perform

T = 0, perform

T = 2, perform where is the complex conjugate of A. Only meaningful when A is complex.

T = 3, perform where is the complex conjugate of A. Only meaningful when A is complex.

SIGNAB Integer-input-default = 1. Sign of product flag.

SIGNAB = +1, perform

SIGNAB = -1, perform

SIGNC Integer-input-default = 1. Sign of flag.

SIGNC = +1, add

SIGNC = -1, subtract

PREC Integer-input-default = 0. Precision.

PREC = 1, element of will be output in single precision.

PREC = 2, elements of will be output in double precision.

PREC = 0, elements of will be output in the precision of the computer.

FORM Integer-input-default = 0. Form of .

FORM = 0, form of will be 1 (square) or 2 (rectangular).

DODMP DMP flag, default = 0

DODMP = 0, compute in serial

DODMP = 1, do distributed memory method 1

DODMP = 2, do distributed memory method 2

SENDIN (DMP only) broadcast input matrices from Master to Slaves

SENDOUT (DMP only) broadcast [D] matrix from Master to Slaves

A[ ]TB[ ]

A[ ] B[ ]

A[ ] B[ ] A[ ]

A[ ]T

B[ ] A[ ]

A[ ] B[ ]

A[ ]– B[ ]

C[ ]

C[ ]

C[ ]

X[ ]

X[ ]

X[ ]

X[ ]

X[ ]

54

MSC.Nastran 2005 Release Guide+%ion

CHAPTER

4 Elements

� Fastener Element (CFAST)

� Element Summary Printout (ELSUM)

� Spatial Dependent Heat Transfer Coefficient

� Two-Variable Heat Transfer Coefficient Tabular Function

� Flux Output Modification for Thermal Analysis

� Arbitrary Beam Cross Section (Pre-Release)

56

4.1 Fastener Element (CFAST)

IntroductionThe Weld family of elements enables you to connect surfaces with differing mesh densities and using a subset of spot weld elements you can connect more than one element per surface. Adding to the family of weld elements, a new CFAST element and its corresponding PFAST property entry are available in MSC.Nastran 2005 r2.

The new CFAST element extends existing weld element capabilities by adding a flexible, user-defined connection between either two surface patches or two shell elements. The PFAST entry gives the option of specifying longitudinal and rotational stiffness, a lumped mass, and damping along a defined orientation.

When used with the new CFDIAGP and CFRANDEL parameters, you can elect to randomly remove a percentage of elements and look at potential failures for the connection.

BenefitsThe existing weld elements focus on providing flexibility and capability at the connection points and the manner in which the connector is defined. These elements enable patch-to-patch or shell-to-shell connections, multi-element connections, and alternate methods for projecting the connection onto the two surfaces. Previously the connector itself was considered to be rigid in user defined degrees-of-freedom.

The new CFAST element encompasses these capabilities and adds the ability to define the properties of the connector itself. Introducing connector flexibility, mass, and damping extends the use of the cweld.

InputThe element connectivity is defined using the new CFAST Bulk Data entry and properties are defined on the corresponding PFASTentry.

New CFAST Bulk Data Entries

57CHAPTER 4Elements

Defines a fastener with material orientation connecting two surface patches.

Format:

Example using PROP:

Example using ELEM:

CFAST A Shell Patch Fastener Connection

1 2 3 4 5 6 7 8 9 10

CFAST EID PID TYPE IDA IDB GS GA GB

XS YS ZS

CFAST 3 20 PROP 21 24 206

CFAST 7 70 ELEM 27 74 707

Field Contents

EID Element identification number. (0 < Integer < 100,000,000)

PID Property identification number of a PFAST entry. (Integer > 0; Default = EID)

TYPE Specifies the surface patch definition: (Character)If TYPE = ‘PROP’, the surface patch connectivity between patch A and patch B is defined with two PSHELL (or PCOMP) properties with property ids given by IDA and IDB. See Remark 1. and Figure 4-1.If TYPE = ‘ELEM’, the surface patch connectivity between patch A and patch B is defined with two shell element ids given by IDA and IDB. See Remark 1. and Figure 4-1.

IDA,IDB Property id (for PROP option) or Element id (for ELEM option) defining patches A and B. (Integer > 0)

GS Grid point defining the location of the fastener. See Remark 2. (Integer > 0 or blank)

GA,GB Grid ids of piecing points on patches A and B. See Remark 2. (Integer > 0 or blank)

XS,YS,ZS Location of the fastener in basic. Required if neither GS nor GA is defined. See Remark 2. (Real or blank)

IDA IDB≠

58

Remarks:

1. The CFAST defines a flexible connection between two surface patches. Depending on the location for the piercing points GA and GB, and the size of the diameter D (see PFAST), the number of unique physical grids per patch ranges from a possibility of 3 to 16 grids. (Currently there is a limitation that there can be only a total of 16 unique grids in the upper patch and only a total of 16 unique grids in the lower patch. Thus, for example, a patch can not hook up to four CQUAD8 elements with midside nodes and no nodes in common between each CQUAD8 as that would total to 32 unique grids for the patch.)

Figure 4-1 Patches Defined with TYPEj= ‘PROP’ or TYPE = ‘ELEM’

2. GS defines the approximate location of the fastener in space. GS is projected onto the surface patches A and B. The resulting piercing points GA and GB define the axis of the fastener. GS does not have to lie on the surfaces of the patches. GS must be able to project normals to the two patches. GA can be specified in lieu of GS, in which case GS will be ignored. If neither GS nor GA is specified, then (XS, YS, ZS) in basic must be specified.

If both GA and GB are specified, they must lie on or at least have projections onto surface patches A and B respectively. The locations will then be corrected so that they lie on the surface patches A and B within machine precision. The length of the fastener is the final distance between GA and GB. If the length is zero, the normal to patch A is used to define the axis of the fastener.

D

L

SHIDB

SHIDA

PIDA

PIDB

GS

GB

GA

59CHAPTER 4Elements

Diagnostic print outs, checkout runs and control of search and projection parameters are requested on the SWLDPRM Bulk Data entry.

3. The use of param,cfdiagp,yes and param,cfrandel,real_fraction_value allows for the random removal of a percentage of CFAST elements for failure studies.

60

Defines the CFAST fastener property values.

Format:

Example:

Remarks:

1.

a. If MCID > 0 and MFLAG = 0 (default), then the KT1 stiffness will be applied along the axis direction of the fastener defined as

PFAST CFAST Fastener Property

1 2 3 4 5 6 7 8 9 10

PFAST PID D MCID MFLAG KT1 KT2 KT3 KR1

KR2 KR3 MASS GE

PFAST 7 1.1 70 100000. 46000. 12300.

Field Contents

PID Property identification number. (Integer > 0)

D Diameter of the fastener. See Remark 2. (Real > 0)

MCID Specifies the element stiffness coordinate system. See Remark 1. (Integer > -1 or blank, Default = -1)

MFLAG Defines if the coordinate system defined by MCID is absolute or relative. See Remark 1. (Integer 0 or 1, Default = 0)If MFLAG = 0, MCID defines a relative coordinate system. See Remark 1a.If MFLAG = 1, MCID defines an absolute coordinate system. See Remark 1c.

KTi Stiffness values in directions 1 through 3. (Real)

KRi Rotational stiffness values in directions 1 through 3. (Real, Default = 0.0)

MASS Lumped mass of fastener. (Real, Default = 0.0)

GE Structural damping. (Real, Default = 0.0)

xelem

e1xB xA–

xB xA–--------------------------=

61CHAPTER 4Elements

The T2 direction defined by MCID will be used to define the orientation vector of the fastener. Then the element axis will be defined as

The KT3 stiffness will lie along the axis. The element axis is defined as

The KT2 stiffness will lie along the axis

This option allows the user to define orthotropic material properties normal to the axis of the fastener that will “slide” with the curve of the patches.

b. If MICD = -1, MFLAG is ignored, and the following element system is defined: the axis direction of the fastener defined as

Relative to the basic system, find the smallest component of the element axis unit vector. If two such components are equal, take the first one.

Form a unit vector in the basic system. For example, assuming the component of was the smallest.

Form the following orthogonal vector:

Form as

υ zelem

e3e1 υ×

e1 υ×-----------------------=

zelem yelem

e2 e3= e1×

yelem

xelem

e1xB xA–

xB xA–--------------------------=

jxelem

j 3=e1

bj b3

001

= =

e2 bj=e1 bj⋅

e1 e1⋅----------------- e1–

e2e2

e2-----------=

e3

e3 e1= e2×

62

c. If MCID > 0 and MFLAG = 1, then the material system directions will be used to compute stiffness. KT1 will be applied along the material T1 axis, KT2 along the material T2 axis, and KT3 along the material T3 axis. The element forces will be computed in the coordinate system defined in Remark 1b.

d. If the length of GA - GB is zero, then the element axis is defined to lie along the projected normal to patch A.

2. The diameter D is used along with the piercing points of GA and GB to determine the location of fictitious grid points to form a fictitious hexa volume that determines the elements and physical grids used for the fastener element. Four points are positioned at positions parallel to the element axis where . The stiffness contribution of the fastener depends on both the stiffness values specified and the diameter D. It is a function of D, because the positions are used along with the surface shape functions of the fictitious hexa to weight the contribution of the physical grids used to the grids GA and GB of the fastener element.

3. The CFAST element (see Figure 4-2), for stiffness and structural damping calculations, is designed to satisfy rigid body equilibrium requirements. When has finite length, internal rigid links connect grids GA and GB. This may result in coupling between translational and rotational degrees-of freedom even when no rotational stiffness (KR1-KR3) are specified.

For mass calculations, half the specified mass value is placed directly onto the projected grid A and grid B translational degrees-of-freedom.

Figure 4-2 CFAST Element

4. The CFAST element lies midway between GA and GB.

xelem

a±a f D( )=

a±

xB xA–

GA

GB

v

zelem

yelem

xelem

location

63CHAPTER 4Elements

5. Values for and are specified at the user’s discretion. Assuming a short stubby beam where shear is dominate, possible values might be:

where

, , , and G are the material properties of the fastener.

The fastener stiffness is not, however, independent of the surrounding structure. The values of stiffness specified should not overwhelm the stiffness of the local structure or max ratio’s will occur. One possible way to estimate the local stiffness is by the relationship.

=

=

=

=

=

=

KTi KRi

KT1 EAL

-------=

KT2G2As

L-------------=

KT3G3As

L-------------=

KR1 GJL

-------=

KR2 EIL------=

G2AsL

3-----------------+

KR3 EIL------=

G3AsL

3-----------------+

A πD2 4⁄

I πD4 64⁄

J πD4 32⁄

L xB xA–

As As A αs⁄=

αs 4 3⁄

E G2 G3

S

64

where is a shell thickness and is the modulus of the shell.

6. The element force and strain are computed as follows:

for statics

for frequency

for transient

where is the 6 x 6 element stiffness matrix, relative displacement in the element coordinate system, and relative velocity in the element coordinate system. The subscripts and stand for end A and end B of the fastener. is defined by param,g; is defined by param,w3, is defined by param,w4; and is the GE entry of the PFAST. is the strain output. Stress output is the same as force output.

StpEpE

Ep E+------------------=

tp Ep

fe{ } Ke[ ] ue{ }=

fe{ } Ke[ ] i g ge+( ) Ke[ ]+( ) ue{ }real

i ue{ }imag

+( )=

fe{ } Ke[ ] ue{ }=g

w3-------

ge

w4-------+

Ke[ ] υe{ }+

Ke[ ] ue{ } ub{ }= ua{ }–

υe{ } υb{ }= υa{ }–

a bg w3

w4 ge

ue{ }

65CHAPTER 4Elements

New Parameters for CFAST

These two new parameters enable you to randomly remove a percentage of CFAST elements for failure studies.

The details can be found in the “CWELD Element Enhancements” on page 239 of the MSC.Nastran Reference Guide.

OutputThe CFAST has element force output, element stress output which is identical to the force output, and element strain output which is simply the relative displacement between ends A and B of the weld.

Guidelines and LimitationsThe following guidelines are associated with the capability:

1. Currently the CFAST and CWELD options do not work with parts superelements. They both work with regular superelements.

2. The CFAST and CWELD use SWLDPRM Bulk Data entry to control projection logic.

The combined use of PARAM,CFDIAG,YES and PARAM,CFRANDEL,real_fraction allows MSC.Nastran to randomly delete a percentage of fastener elements.

The Connector Elements (CFAST and CWELD) are supported in MDACMS but not in GDACMS.

It is recommended that PRTSW 1 and CHKRUN 1 initially be used on the SWLDPRM entry to insure that the connections are reasonable.

CFDIAGP Default = NO

If YES, randomly deleted CFAST elements will be printed. (See CFRANDEL)

CFRANDEL Default = 0.

Represents a percent, expressed as a decimal fraction, of the number of CFAST elements to be randomly deleted.

66

If a CFAST is near the edge of a part it may not be able to project four points necessary to form a connection. Setting the nredia<4 or gsmove>1 or both, on the SWLDPRM often will help correct the problem.

If the CFAST encounters shape angles between plate elements when trying to form the projection it may not be able to find a shell element. Increasing the projtol on the SWLDPRM often will help correct the problem.

Examples

Example 1

The first example (f_qa.dat located in the examples folder) is two 3x3 structures made up of 9 cquad4 elements each laid over each other and connected with a single CFAST element located at the center of each structure.

The diameter of the fastener was chosen so that the fastener would pick up 4 different elements for patch A and four different elements for patch B. Thus for this weld, a total of 32 different grids are involved in the connector.

Input

The input (relevant entries only) is shown below:

sol 101cendload = 10set 7 = 777force=7begin bulkswldprm prtsw 1$cfast,777,1000,elem,105,5,999pfast,1000,30.,,,1.18+8,4.53+8,4.53+8,5.09+9,6.62+9,6.62+9enddata

Output

The listings below show relevant output for the CFAST element and a typical force output.

67CHAPTER 4Elements

Example 2

The next example (fse_rg.dat- located in the examples folder) represents two plate structures modeled as two superelements with a slight overlap so that they could be connected with the fastener element.

Input

The input data (relevant entries only) is:

sol 101cendload = 10spc = 10set 55 = 8777,9776,9778force=55begin bulk$swldprm prtsw 1 nredia 1 gsmove 3 $pfast,2000,6.,,,2.356+7,9.062+6,9.062+6,4.078+7,5.3+7,5.3+7cfast,8777,2000,elem,211,1211,, 312cfast,9776,2000,elem,71,1071,999cfast,9778,2000,prop,2,20,10.5,15.5,.005$grid 999 10.5 3.5 .005$spc1 10 123456 1 301 601enddata

CFAST EID= 777 WITH FORM=ELPAT OR PARTPAT AUXILIARY POINTS= ( 1.7066E+00, 1.7066E+00, 0.0000E+00) ( 2.8293E+01, 1.7066E+00, 0.0000E+00) ( 2.8293E+01, 2.8293E+01, 0.0000E+00) ( 1.7066E+00, 2.8293E+01, 0.0000E+00) ( 1.7066E+00, 1.7066E+00, 1.0000E-02) ( 2.8293E+01, 1.7066E+00, 1.0000E-02) ( 2.8293E+01, 2.8293E+01, 1.0000E-02) ( 1.7066E+00, 2.8293E+01, 1.0000E-02) NUMBER OF TIMES GS MOVES= 0 NUMBER OF TIMES DA IS REDUCED= 0 ANGLE BETWEEN TWO SHELL NORMALS= 0.00 GS=( 1.500E+01, 1.500E+01, 5.000E-03) GA=( 1.500E+01, 1.500E+01, 0.000E+00) GB=( 1.500E+01, 1.500E+01, 1.000E-02) T_BE MATRIX: 0.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 1.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 PATCH A: EID= 101 GIDS= 201 202 206 205 0 0 0 0 EID= 103 GIDS= 203 204 208 207 0 0 0 0 EID= 109 GIDS= 211 212 216 215 0 0 0 0 EID= 107 GIDS= 209 210 214 213 0 0 0 0 PATCH B: EID= 1 GIDS= 101 102 106 105 0 0 0 0 EID= 3 GIDS= 103 104 108 107 0 0 0 0 EID= 9 GIDS= 111 112 116 115 0 0 0 0 EID= 7 GIDS= 109 110 114 113 0 0 0 0

F O R C E S I N F A S T E N E R E L E M E N T S ( C F A S T ) ELEMENT_ID FORCE-X FORCE-Y FORCE-Z MOMENT-X MOMENT-Y MOMENT-Z 777 2.620126E-08 2.000000E+03 3.628412E-10 -1.655577E-09 -1.952258E-07 1.000000E+01 * * * END OF JOB * * *

68

Output

A representative sample of the output is shown below.

1697- SWLDPRM PRTSW 1 NREDIA 1 GSMOVE 3 ENDDATA M O D E L S U M M A R Y NUMBER OF GRID POINTS = 883 NUMBER OF CFAST ELEMENTS = 3 NUMBER OF CQUAD4 ELEMENTS = 800 CFAST EID= 8777 WITH FORM=ELPAT OR PARTPAT DA IS REDUCED BY HALF TO 1.3293E+00 GS IS MOVED FROM ( 1.1000E+01, 1.0000E+01, 0.0000E+00) TO ( 1.0335E+01, 1.0665E+01, 2.5000E-03) *** USER WARNING MESSAGE 7636 (MDG2ED) FOR CFAST ELEMENT ID= 8777, WITH FORM=ELPAT OR PARTPAT, THE CENTER LOCATION IS MOVED FROM ( 1.1000E+01, 1.0000E+01, 0.0000E+00) TO ( 1.0335E+01, 1.0665E+01, 2.5000E-03) BY (-6.6467E-01, 6.6467E-01, 2.5000E-03) WITH ABSOLUTE DISTANCE= 9.3999E-01 TO GET A PROJECTION INSIDE THE DEFINED SHELL PATCHES. AUXILIARY POINTS= ( 9.0060E+00, 9.3353E+00, 0.0000E+00) ( 1.1665E+01, 9.3353E+00, 0.0000E+00) ( 1.1665E+01, 1.1994E+01, 0.0000E+00) ( 9.0060E+00, 1.1994E+01, 0.0000E+00) ( 9.0060E+00, 9.3353E+00, 1.0000E-02) ( 1.1665E+01, 9.3353E+00, 1.0000E-02) ( 1.1665E+01, 1.1994E+01, 1.0000E-02) ( 9.0060E+00, 1.1994E+01, 1.0000E-02) NUMBER OF TIMES GS MOVES= 1 NUMBER OF TIMES DA IS REDUCED= 1 ANGLE BETWEEN TWO SHELL NORMALS= 0.00 GS=( 1.034E+01, 1.066E+01, 2.500E-03) GA=( 1.034E+01, 1.066E+01, 0.000E+00) GB=( 1.034E+01, 1.066E+01, 1.000E-02) T_BE MATRIX: 0.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 1.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 PATCH A: EID= 190 GIDS= 280 281 311 310 0 0 0 0 EID= 192 GIDS= 282 283 313 312 0 0 0 0 EID= 232 GIDS= 342 343 373 372 0 0 0 0 EID= 230 GIDS= 340 341 371 370 0 0 0 0 PATCH B: EID= 1190 GIDS= 1280 1281 1311 1310 0 0 0 0 EID= 1192 GIDS= 1282 1283 1313 1312 0 0 0 0 EID= 1232 GIDS= 1342 1343 1373 1372 0 0 0 0 EID= 1230 GIDS= 1340 1341 1371 1370 0 0 0 0

CFAST EID= 9776 WITH FORM=ELPAT OR PARTPAT DA IS REDUCED BY HALF TO 1.3293E+00 AUXILIARY POINTS= ( 9.1707E+00, 2.1707E+00, 0.0000E+00) ( 1.1829E+01, 2.1707E+00, 0.0000E+00) ( 1.1829E+01, 4.8293E+00, 0.0000E+00) ( 9.1707E+00, 4.8293E+00, 0.0000E+00) ( 9.1707E+00, 2.1707E+00, 1.0000E-02) ( 1.1829E+01, 2.1707E+00, 1.0000E-02) ( 1.1829E+01, 4.8293E+00, 1.0000E-02) ( 9.1707E+00, 4.8293E+00, 1.0000E-02) NUMBER OF TIMES GS MOVES= 0 NUMBER OF TIMES DA IS REDUCED= 1 ANGLE BETWEEN TWO SHELL NORMALS= 0.00 GS=( 1.050E+01, 3.500E+00, 5.000E-03) GA=( 1.050E+01, 3.500E+00, 0.000E+00) GB=( 1.050E+01, 3.500E+00, 1.000E-02) T_BE MATRIX: 0.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 1.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 PATCH A: EID= 50 GIDS= 70 71 101 100 0 0 0 0 EID= 52 GIDS= 72 73 103 102 0 0 0 0 EID= 92 GIDS= 132 133 163 162 0 0 0 0 EID= 90 GIDS= 130 131 161 160 0 0 0 0 PATCH B: EID= 1050 GIDS= 1070 1071 1101 1100 0 0 0 0 EID= 1052 GIDS= 1072 1073 1103 1102 0 0 0 0 EID= 1092 GIDS= 1132 1133 1163 1162 0 0 0 0 EID= 1090 GIDS= 1130 1131 1161 1160 0 0 0 0

69CHAPTER 4Elements

Example 3

In this last example, notice that a SWLDPRM Bulk Data entry was needed.

For CFAST 8777, the grid GA location was given which placed it too close to the free edge of the superelement. The GSMOVE specified allowed for the algorithm to move the GS point away from the edge. Also the chosen diameter was such that it tried to pick up element beyond the superelement edge. The NREDIA specified allowed the algorithm to reduce the diameter to fit at least within an element. CFAST 9776 and 9778 also both required the use of the NREDIA entry. Note, however, that for these two CFAST elements, no gsmove took place.

CFAST EID= 9778 WITH FORM=ELPAT OR PARTPAT DA IS REDUCED BY HALF TO 1.3293E+00 AUXILIARY POINTS= ( 9.1707E+00, 1.4171E+01, 0.0000E+00) ( 1.1829E+01, 1.4171E+01, 0.0000E+00) ( 1.1829E+01, 1.6829E+01, 0.0000E+00) ( 9.1707E+00, 1.6829E+01, 0.0000E+00) ( 9.1707E+00, 1.4171E+01, 1.0000E-02) ( 1.1829E+01, 1.4171E+01, 1.0000E-02) ( 1.1829E+01, 1.6829E+01, 1.0000E-02) ( 9.1707E+00, 1.6829E+01, 1.0000E-02) NUMBER OF TIMES GS MOVES= 0 NUMBER OF TIMES DA IS REDUCED= 1 ANGLE BETWEEN TWO SHELL NORMALS= 0.00 GS=( 1.050E+01, 1.550E+01, 5.000E-03) GA=( 1.050E+01, 1.550E+01, 0.000E+00) GB=( 1.050E+01, 1.550E+01, 1.000E-02) T_BE MATRIX: 0.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 1.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 PATCH A: EID= 290 GIDS= 430 431 461 460 0 0 0 0 EID= 292 GIDS= 432 433 463 462 0 0 0 0 EID= 332 GIDS= 492 493 523 522 0 0 0 0 EID= 330 GIDS= 490 491 521 520 0 0 0 0 PATCH B: EID= 1290 GIDS= 1430 1431 1461 1460 0 0 0 0 EID= 1292 GIDS= 1432 1433 1463 1462 0 0 0 0 EID= 1332 GIDS= 1492 1493 1523 1522 0 0 0 0 EID= 1330 GIDS= 1490 1491 1521 1520 0 0 0 0

SUPERELEMENT 9999 F O R C E S I N F A S T E N E R E L E M E N T S ( C F A S T ) ELEMENT_ID FORCE-X FORCE-Y FORCE-Z MOMENT-X MOMENT-Y MOMENT-Z 8777 1.562788E+00 1.322742E+02 -7.590701E+02 -1.351996E+03 6.868579E+00 1.646796E-01 9776 1.151554E+00 8.056281E+02 1.838513E+02 6.724717E+02 3.327260E+00 1.887241E+00 9778 -1.077622E+00 6.643287E+02 1.967240E+02 -5.113867E+02 3.264459E+00 4.065171E+00

70

4.2 Element Summary Printout (ELSUM)

IntroductionThe ELSUM Case Control command provides the ability to generate a printed table of properties for the various element types present in the input data file. Using ELSUM, you can produce element measures (e.g., length, thickness, area, volume) and mass property data. In addition, a new keyword, NSMCONT, has been introduced for the ELSUM command in MSC.Nastran 2005 r2. This option enables you to also request detailed information on the nonstructural mass contribution to the element mass when NSM-type Bulk Data entries are selected with the NSM Case Control command.

BenefitsThis addition to the ELSUM Case Control command enables you to verify that the nonstructural mass assigned to an element is what you expect. Contributions to the total nonstructural mass of an element can now originate from several sources. The element property Bulk Data entry is the traditional source of nonstructural mass. With the introduction of the NSM-type Bulk Data entries in MSC.Nastran 2004, nonstructural mass contributions can now be generated by reference to those entries as well. The total nonstructural mass is the combination of contributions from all sources. If there is an inadvertent input data error using the NSM-type Bulk Data entries, it is difficult to detect without detailed information that identifies the contribution from each possible source. The new NSMCONT keyword of the ELSUM Case Control command introduces the ability to generate this detailed output. This improves your productivity by reducing the amount of time spent searching for input data errors.

InputA new keyword, NSMCONT, has been introduced for the ELSUM Case Control command. This keyword adds nonstructural mass source contribution information to the standard .f06 output file.

OutputThe ELSUM Case Control command causes printed output to be generated. The NSMCONT keyword causes additional printed output associated with nonstructural mass to be generated when NSM-type Bulk Data entries are selected by the NSM Case Control command.

71CHAPTER 4Elements

Guidelines and LimitationsDetailed nonstructural mass information is generated only if there is a NSM Case Control command present that selects NSM-type Bulk Data entries. Reference to those entries actually generates nonstructural mass contributions for an element.

Output is generated only for those element types that support nonstructural mass calculations.

ExampleA simple example is presented that demonstrates the use of the NSMCONT keyword of the ELSUM Case Control command. The model data in the example below consists of a series of disjoint, possibly overlapping, elements assembled to exercise the NSM features available in this version of MSC.Nastran. The ELSUM command is introduced to generate the detailed output for the nonstructural mass.

The partial input and output listings below highlight some key information relating to ELSUM feature and the new NSMCONT keyword. For access to the full example problem files, see “Example Problems” in Chapter 1.

Input

$NASTRAN SYSTEM(361)=1SOL 108 $ DIRECT FREQ RESP ANALYSISCEND$elsum(eid,nsmcont) = all$set 9999 = 1002$ DISPL = 9999 DLOAD = 185 MPC = 1 FREQ = 120 NSM = 1222BEGIN BULK$param,grdpnt,0GRID 777 10. 0. 0.$CELAS1 171 175 777 1 0 0CELAS1 172 175 777 2 0 0PELAS 175 11. .2

ELSUM Case Control command w/ NSNCONT

72

$

$ ELM NSM ID PID PROPERTY PNSM$ ---- --- -- --- ------- ----$ CBAR(34) .061 25 22 - PBAR .013$ CBAR(34) .039 26 26 - PBARL .013$ CBEAM(2) .065 20 21 - PBCOMP .011$ .065

$$ 2 3 4 5 6 7 8 9 0$ 201 301 401 beamNSM 9 PBEAM 211 .013 311 .014 411 .015$ 27 37 bendNSM 9 PBEND 21 .031 31 .031$ 101 crac2dNSM 10 PRAC2D 1 .033$ 20 30 40 beam

$ 25 35 45 shearNSM 18 PSHEAR 1 .123$ beam beamNSM1 19 ELEMENT .028 201 402$ t3 t6 t3NSM1 19 ELEMENT .028 3123 6134 134NSMADD 1222 9 10 11 12 13 14 15 16NSMADD 1222 17 18 19$nsmadd,1222,1001,1002,1003,1004nsml,1001,prod,12,.13nsml1,1002,prod,.13,12nsml,1003,element,13,.13nsml1,1004,element,.13,13$$------------------------------------------------$FORCE 85 2 1. 1000. -1.7FORCE 85 3 1. 1000. -1.7$RLOAD1 185 85 581TABLED1 581 1. 1. 10000. 1. ENDT$FREQ1 120 10. 5. 2$ENDDATA

Nonstructural Mass entries w/ property and element options

Lumped Nonstructural Mass IDs using property and element options

73CHAPTER 4Elements

Output

This example problem contains most of the supported element types. Nonstructural mass contributions are selected for elements by the NSM=1222 Case Control command. This command selects NSM-type Bulk Data entries by referencing the NSMADD Bulk Data entry that combines various NSM-type entries with different set IDs.

This first listing contains fragments from the .f06 file showing the nonstructural mass contribution outputs for element type/ID combination using the ELSUM(EID,NSMCONT)=ALL command. The nonstructural mass contribution outputs are identified under the PROP ID heading by their NSM-type Bulk Data entry and ID and under the NON-STR. MASS heading with their contribution to the total non-structural mass of the element. This listing shows only a representative sample of element types.

E L E M E N T P R O P E R T Y S U M M A R Y (BY ELEMENT TYPE / ID)

ELEMENT TYPE = BAR NSM OR NSM = 1222 ELEM ID PROP ID MATL ID LENGTH AREA VOLUME STRUCT.MASS NON-STR.MASS TOTAL MASS TM*WTMASS 25 22 1 1.00000E+01 2.00000E-02 2.00000E-01 0.00000E+00 6.10000E-01 6.10000E-01 6.10000E-01 NSM (P) 15 (2.60000E-01) NSM (E) 15 (2.20000E-01) NSM (SUBTOTAL) =(4.80000E-01)= 26 26 L 1 1.00000E+01 3.14159E-02 3.14159E-01 0.00000E+00 3.90000E-01 3.90000E-01 3.90000E-01 NSM (P) 15 (2.60000E-01) ----------- ----------- ----------- ----------- SUBTOTAL MASS FOR ALL BAR 0.00000E+00 1.00000E+00 1.00000E+00 1.00000E+00 SUBTOTAL NSM (E) =(2.20000E-01)= SUBTOTAL NSM (P) =(5.20000E-01)=

ELEMENT TYPE = BEAM NSM OR NSM = 1222 ELEM ID PROP ID MATL ID LENGTH AREA VOLUME STRUCT.MASS NON-STR.MASS TOTAL MASS TM*WTMASS 20 21 1 2.00000E+00 1.20080E-02 2.40160E-02 0.00000E+00 1.30000E-01 1.30000E-01 1.30000E-01 NSM (P) 10 (4.20000E-02) NSM (E) 14 (6.60000E-02) NSM (SUBTOTAL) =(1.08000E-01)= 30 31 1 2.00000E+00 1.20080E-02 2.40160E-02 0.00000E+00 1.30000E-01 1.30000E-01 1.30000E-01 NSM (P) 10 (4.20000E-02) NSM (E) 14 (6.60000E-02) NSM (SUBTOTAL) =(1.08000E-01)= 40 41 1 2.00000E+00 1.20080E-02 2.40160E-02 0.00000E+00 1.30000E-01 1.30000E-01 1.30000E-01 NSM (P) 10 (4.20000E-02) NSM (E) 14 (6.60000E-02)

ELEMENT TYPE = CONROD NSM OR NSM = 1222 ELEM ID PROP ID MATL ID LENGTH AREA VOLUME STRUCT.MASS NON-STR.MASS TOTAL MASS TM*WTMASS 12 0 51 1.00000E+01 1.10000E+00 1.10000E+01 6.60000E-01 3.20000E-01 9.80000E-01 9.80000E-01 NSM (P) 12 (1.90000E-01) 121 0 51 1.00000E+01 1.10000E+00 1.10000E+01 6.60000E-01 1.32000E+00 1.98000E+00 1.98000E+00 NSM (P) 12 (1.19000E+00) ----------- ----------- ----------- ----------- SUBTOTAL MASS FOR ALL CONROD 1.32000E+00 1.64000E+00 2.96000E+00 2.96000E+00 SUBTOTAL NSM (P) =(1.38000E+00)=

ELEMENT TYPE = QUAD4 NSM OR NSM = 1222 ELEM ID PROP ID MATL ID THICKNESS AREA VOLUME STRUCT.MASS NON-STR.MASS TOTAL MASS TM*WTMASS 41 57 P 57 2.00000E-01 1.00000E+02 2.00000E+01 5.04009E+01 2.57000E+01 7.61009E+01 7.61009E+01 NSM (P) 13 (8.80000E+00) NSM (P) 14 (7.50000E+00)

TOTAL MASS FOR ALL SUPPORTED ELEMENT TYPES 2.00569E+02 3.02556E+02 5.03126E+02 5.03126E+02 =========== =========== =========== =========== SUBTOTAL NSM (E) =(2.36910E+01)= SUBTOTAL NSM (P) =(2.57098E+02)= SUBTOTAL NSML(E) =(2.60000E-01)= SUBTOTAL NSML(P) =(2.60000E-01)=

74

This second listing also contains fragments from the .f06 file showing the nonstructural mass contribution outputs for property type/ID combination using the ELSUM(PID,NSMCONT)=ALL command. The portion of the nonstructural mass contributed by each of the NSM-type Bulk Data entries is printed. In addition, the total nonstructural mass contribution from all elements that reference the property entry is summarized on the header line. A trailing summary line indicates the portion of the nonstructural mass that is contributed by the value in the NSM field of the property entry itself. If the SUMMARY keyword is also included in the ELSUM command, a final summary table (not shown) is also produced that contains output for each property type and ID.

1 0 E L E M E N T P R O P E R T Y S U M M A R Y (BY PROPERTY TYPE / ID)

PROPERTY TYPE = PBAR, ID = 22, (NSM SID = 1222, PROP ID TOTAL NSM = 6.10000E-01) ******************************* NSM ID NSM (E) NSM (P) NSML(E) NSML(P) TOTAL SUM 15 2.20000E-01 2.60000E-01 0.00000E+00 0.00000E+00 4.80000E-01 (CONTRIBUTION OF PBAR, ENTRY NSM VALUE TO PROP ID TOTAL NSM = 1.30000E-01)

PROPERTY TYPE = PBARL, ID = 26, (NSM SID = 1222, PROP ID TOTAL NSM = 3.90000E-01) ******************************* NSM ID NSM (E) NSM (P) NSML(E) NSML(P) TOTAL SUM 15 0.00000E+00 2.60000E-01 0.00000E+00 0.00000E+00 2.60000E-01 (CONTRIBUTION OF PBARL, ENTRY NSM VALUE TO PROP ID TOTAL NSM = 1.30000E-01) -------------------------------------------------------------------------------------------------------------------- 2.20000E-01 5.20000E-01 0.00000E+00 0.00000E+00 7.40000E-01 (TOTALS FOR ALL PROPERTY IDS) --------------------------------------------------------------------------------------------------------------------

PROPERTY TYPE = PBEND, ID = 21, (NSM SID = 1222, PROP ID TOTAL NSM = 1.71217E+00) ******************************* NSM ID NSM (E) NSM (P) NSML(E) NSML(P) TOTAL SUM 9 0.00000E+00 4.86947E-01 0.00000E+00 0.00000E+00 4.86947E-01 16 1.02102E+00 0.00000E+00 0.00000E+00 0.00000E+00 1.02102E+00 (CONTRIBUTION OF PBEND, ENTRY NSM VALUE TO PROP ID TOTAL NSM = 2.04203E-01)

PROPERTY TYPE = PBEND, ID = 31, (NSM SID = 1222, PROP ID TOTAL NSM = 6.91150E-01) ******************************* NSM ID NSM (E) NSM (P) NSML(E) NSML(P) TOTAL SUM 9 0.00000E+00 4.86947E-01 0.00000E+00 0.00000E+00 4.86947E-01 (CONTRIBUTION OF PBEND, ENTRY NSM VALUE TO PROP ID TOTAL NSM = 2.04204E-01) -------------------------------------------------------------------------------------------------------------------- 1.02102E+00 9.73894E-01 0.00000E+00 0.00000E+00 1.99491E+00 (TOTALS FOR ALL PROPERTY IDS) --------------------------------------------------------------------------------------------------------------------

PROPERTY TYPE = PSHEAR, ID = 1, (NSM SID = 1222, PROP ID TOTAL NSM = 1.89600E+00) ******************************* NSM ID NSM (E) NSM (P) NSML(E) NSML(P) TOTAL SUM 15 2.64000E-01 0.00000E+00 0.00000E+00 0.00000E+00 2.64000E-01 18 0.00000E+00 1.47600E+00 0.00000E+00 0.00000E+00 1.47600E+00 (CONTRIBUTION OF PSHEAR, ENTRY NSM VALUE TO PROP ID TOTAL NSM = 1.56000E-01) -------------------------------------------------------------------------------------------------------------------- 2.64000E-01 1.47600E+00 0.00000E+00 0.00000E+00 1.74000E+00 (TOTALS FOR ALL PROPERTY IDS) --------------------------------------------------------------------------------------------------------------------

PROPERTY TYPE = PTUBE, ID = 14, (NSM SID = 1222, PROP ID TOTAL NSM = 9.70000E-01) ******************************* NSM ID NSM (E) NSM (P) NSML(E) NSML(P) TOTAL SUM 17 4.10000E-01 4.30000E-01 0.00000E+00 0.00000E+00 8.40000E-01 (CONTRIBUTION OF PTUBE, ENTRY NSM VALUE TO PROP ID TOTAL NSM = 1.30000E-01) -------------------------------------------------------------------------------------------------------------------- 4.10000E-01 4.30000E-01 0.00000E+00 0.00000E+00 8.40000E-01 (TOTALS FOR ALL PROPERTY IDS) -------------------------------------------------------------------------------------------------------------------- ==================================================================================================================== 2.36910E+01 2.57098E+02 2.60000E-01 2.60000E-01 2.81309E+02 (TOTALS FOR ALL PROPERTY TYPES) ====================================================================================================================

75CHAPTER 4Elements

4.3 Spatial Dependent Heat Transfer Coefficient

IntroductionA localized heat transfer coefficient is implemented to simulate the non-uniform free convection heat transfer across a single CHBDYi surface element. This functionality also enables you to define a constant free convection heat transfer coefficient directly in the convection property entry (PCONV), instead of referring to a material property entry (MAT4).

InputThe spatial dependent heat transfer coefficient is modeled by the modified PCONV Bulk Data entry. The FTYPE field now enables you to specify the formula type used in computing the convection heat transfer coefficient h.

Specifies the free convection boundary condition properties of a boundary condition surface element used for heat transfer analysis.

Format:

Examples:

Alternate Format and Examples:

PCONV - Convection Property Definition

1 2 3 4 5 6 7 8 9 10

PCONV PCONID MID FORM EXPF FTYPE TID

CHLEN GIDIN CE E1 E2 E3

PCONV 53 2 0 .25

PCONV 4 1 101

PCONV 38 21 2 54

2.0 235 0 1.0 0.0 0.0

1 2 3 4 5 6 7 8 9 10

PCONV PCONID MID FORM EXPF “3” H1 H2 H3

H4 H5 H6 H7 H8

76

Remarks:

1. Every surface to which free convection is to be applied must reference a PCONV entry. PCONV is referenced on the CONV Bulk Data entry.

2. MID is used to supply the convection heat transfer coefficient (H) for FTYPE=0, or the thermal conductivity (K) for FTYPE=2. MID is ignored for FTYPE=1.

3. EXPF is the free convection temperature exponent.

PCONV 20 3 10.0

PCONV 7 3 10.32 10.05 10.09

10.37

Field Contents

PCONID Convection property identification number. (Integer > 0)

MID Material property identification number. (Integer > 0)

FORM Type of formula used for free convection. (Integer 0, 1, 10, 11, 20, or 21; Default = 0)

EXPF Free convection exponent as implemented within the context of the particular form that is chosen. See Remark 3. (Real > 0.0; Default = 0.0)

FTYPE Formula type for various configurations of free convection. See Remarks 2. and 5. (Integer > 0; Default = 0)

TID Identification number of a TABLEHT entry that specifies the two-variable tabular function of the free convection heat transfer coefficient. See Remark 5. (Integer > 0 or blank)

CHLEN Characteristic length. See Remarks 6. and 8. (Real > 0.0 or blank)

GIDIN Grid ID of the referenced inlet point. See Remarks 7. and 8. (Integer > 0 or blank)

CE Coordinate system for defining the direction of boundary-layer flow. See Remarks 7. and 8. (Integer > 0; Default = 0)

Ei Component of the vector for defining the direction of boundary-layer flow in coordinate system CE. See Remarks 7. and 8. (Real or blank)

Hi Free convection heat transfer coefficient. See Remark 5. (Real for H1 and Real or blank for H2 through H8; Default for H2 through H8 is H1)

77CHAPTER 4Elements

• If FORM = 0, 10, or 20, EXPF is an exponent of (T - TAMB), where the convective heat transfer is represented as

.

• If FORM = 1, 11, or 21,

where T represents the elemental grid point temperatures and TAMB is the associated ambient temperature.

4. FORM specifies the formula type and the reference temperature location used in calculating the convection film coefficient if FLMND = 0.

• If FORM = 0 or 1, the reference temperature is the average of element grid point temperatures (average) and the ambient point temperatures (average).

• If FORM = 10 or 11, the reference temperature is the surface temperature (average of element grid point temperatures).

• If FORM = 20 or 21, the reference temperature is the ambient temperature (average of ambient point temperatures).

5. FTYPE defines the formula type used in computing the convection heat transfer coefficient h.

• If FTYPE = 0, h is specified in the MAT4 Bulk Data entry referenced by MID.

• If FTYPE = 1, h is computed from , where f is a two-variable tabular function specified in the TABLEHT Bulk Data entry referenced by TID, is the wall temperature, and is the ambient temperature.

• If FTYPE = 2, h is computed from , where or is the Nusselt number, f is a two-variable tabular function

specified in the TABLEHT Bulk Data entry referred by TID, is the wall temperature, and is the ambient temperature.

• If FTYPE=3, hi is the free convection heat transfer coefficient applied to grid point Gi of the referenced HBDY surface element.

6. CHLEN specifies the characteristic length used to compute the average heat transfer coefficient . The following table lists typical values of CHLEN for various convection configurations.

q H= uCNTRLND T TAMB–( )EXPFT TAMB–( )⋅ ⋅ ⋅

q H= uCNTRLND TEXPF TAMBEXPF

–( )⋅ ⋅

h f Tw Ta,( )=

Tw Ta

Nu f Tw Ta,( )= NuL hL K⁄=

Nux hX K⁄=

Tw

Ta

h

78

7. GIDIN, CE and Ei are used to define the distance from the leading edge of heat transfer. GIDIN specifies the referenced grid ID where heat transfer starts. CE and Ei define the direction of boundary-layer flow. If CE field is blank, the default is CE=0 for basic coordinate system. If E1, E2, and E3 fields are blank, the defaults are Ei = < 1.0, 0.0, 0.0 >, i.e. the flow is in the x direction.

8. CHLEN, GIDIN, CE, and Ei are required only for free convection from flat plates with FTYPE = 2. In this case, if the heat transfer coefficient is spatial dependent, GIDIN must be specified. Otherwise, CHLEN has to be defined for the computation of average heat transfer coefficient . For free convection from tubes (CHBDYP elements with TYPE="ELCY”, “TUBE” or “FTUBE”), CHLEN, GIDIN, CE, and Ei need not be specified, because MSC.Nastran will use the average diameter of tubes as the characteristic length while computing Nu. CHLEN, GIDIN, CE, and Ei are ignored for

.

Convection Configuration Characteristic Length CHLEN

Free convection on a vertical plate or cylinder

Height of the plate or cylinder

Free convection from horizontal tubes

Diameter of the pipes

Free convection from horizontal square plates

Length of a side

Free convection from horizontal rectangular plates

Average length of four sides

Free convection from horizontal circular disks

0.9d, where d is the diameter of the disk.

Free convection from horizontal unsymmetric plates

A/P, where A is the surface area and P is the perimeter of the surface.

h

FTYPE 2≠

79CHAPTER 4Elements

ExampleMSC.Nastran test file: spatial_h_2005.dat

Prior to 2005 r2 MSC.Nastran used an average film coefficient definition per element. Starting with MSC.Nastran 2005 r2 you are able to specify nodal convection coefficients. This feature allows the mapping of each of convection coefficient from a CFD analysis into an MSC.Nastran model.

Figure 4-3 h=h(x)=2.7768/SQRT(x)

Thermal boundary conditions:

1. h =h(x)= 2.7768/SQRT(x)

2. The temperature is fixed at

3. 40 watts is applied to the 9 inch by 5 inch plate

4. At x=0, the h(x) is infinite, and therefore h(x=0.1) is used to evaluate the expression at x=0.

20°C

80

Figure 4-4 Thermal boundary conditions

Input

On the PCONV entry, the FTYPE field is now available to define the formula type used in computing the convection heat transfer coefficient h. If the FTYPE=3, then h1,h2,h3,h4 up to h8 can be added

In this example CHBDYG,AREA4 is used, and so up to 4 local h values can be specified per element.

Note that a MAT4 ID of 302 is referenced; however, this option does not require a MAT4 definition.

MSC.Nastran test file: spatial_h_2005.dat

$ NASTRAN input file created by the MSC MSC.Nastran input file$ translator ( MSC.Patran 12.0.044 ) on August 19, 2004 at 15:38:11.$ Direct Text Input for File Management Section$ Steady State Analysis, DatabaseSOL 153$ Direct Text Input for Executive ControlCENDANALYSIS = HEATTITLE = MSC.Nastran job created on 19-Aug-04 at 15:37:56

81CHAPTER 4Elements

ECHO = NONETEMPERATURE(INITIAL) = 1$ Direct Text Input for Global Case Control DataSUBCASE 1$ Subcase name : Default

QBDY3 2 .88889 100045$ Convection to Ambient of Load Set : 40watt$$pconv,1,3002,0,0.0,3,0.12,0.13,0.14,$p,0.15pconv,1,302,0,0.0,3,8.7810,2.7768,2.7768,,8.7810pconv,2,302,0,0.0,3,2.7768,1.96349,1.96349,,2.7768pconv,3,302,0,0.0,3,1.96349,1.60319,1.60319,,1.96349pconv,4,302,0,0.0,3,1.60319,1.3884,1.3884,,1.60319pconv,5,302,0,0.0,3,1.3884,1.2418,1.2418,,1.3884pconv,6,302,0,0.0,3,1.2418,1.1336,1.1336,,1.2418pconv,7,302,0,0.0,3,1.1336,1.0495,1.0495,,1.1336pconv,8,302,0,0.0,3,1.0495,.98175,.98175,,1.0495pconv,9,302,0,0.0,3,.98175,.9256,.9256,,.98175$$PCONV 1 1001 0 0.CONV 100001 1 0 0 61$PCONV 2 1002 0 0.CONV 100002 2 0 0 61$PCONV 3 1003 0 0.CONV 100003 3 0 0 61$PCONV 4 1004 0 0.CONV 100004 4 0 0 61$PCONV 5 1005 0 0.CONV 100005 5 0 0 61$PCONV 6 1006 0 0.CONV 100006 6 0 0 61

MAT4 1008 1.01394MAT4 1009 .952435$ Scalar PointsSPOINT 61$ Referenced Coordinate FramesENDDATA 9c8617f3

FTYPE=3Free convection coefficients specified at 4 grid points

82

LOAD STEP = 1.00000E+00 H E A T F L O W I N Q U A D R I L A T E R A L E L E M E N T S ( Q U A D 4 ) ELEMENT-ID SIDE HBDY-ID CONV COEFF APPLIED-LOAD CONVECTION RADIATION TOTAL 1 1 100001 5.778900E+00 8.888900E-01 -9.544129E-01 0.000000E+00 -6.552285E-02 2 1 100002 2.370145E+00 8.888900E-01 -8.710693E-01 0.000000E+00 1.782078E-02 3 1 100003 1.783340E+00 8.888900E-01 -8.793325E-01 0.000000E+00 9.557486E-03 4 1 100004 1.495795E+00 8.888900E-01 -8.833646E-01 0.000000E+00 5.525410E-03 5 1 100005 1.315100E+00 8.888900E-01 -8.852076E-01 0.000000E+00 3.682435E-03 6 1 100006 1.187700E+00 8.888900E-01 -8.860430E-01 0.000000E+00 2.847075E-03 7 1 100007 1.091550E+00 8.888900E-01 -8.859066E-01 0.000000E+00 2.983391E-03 8 1 100008 1.015625E+00 8.888900E-01 -8.832566E-01 0.000000E+00 5.633414E-03 9 1 100009 9.536750E-01 8.888900E-01 -8.714170E-01 0.000000E+00 1.747298E-02 10 1 100010 5.778900E+00 8.888900E-01 -9.544129E-01 0.000000E+00 -6.552285E-02

83CHAPTER 4Elements

4.4 Two-Variable Heat Transfer Coefficient Tabular Function

IntroductionA two-variable tabular function of heat transfer coefficient, is implemented to simulate the empirical correlations for free convection. This functionality also provides the capability of modeling the free convection heat transfer on a flat plate. The heat transfer coefficient is recalculated based on element location, element temperature, and ambient temperature at each iteration or each time step.

InputThe two-variable tabular input is modeled by the new TABLEHT and TABLEH1 Bulk Data entries and the modified PCONV Bulk Data entry.

Specifies a function of two variables for convection heat transfer coefficient.

Format:

Example:

Remarks:

1. xi must be listed in ascending order.

2. At least one continuation entry must be present.

TABLEHT - Heat Transfer Coefficient Table with Two Variables

1 2 3 4 5 6 7 8 9 10

TABLEHT TID

x1 TID1 x2 TID2 x3 -etc.

TABLEHT 85

10.0 101 25.0 102 40.0 110 ENDT

Field Contents

TID Table identification number. (Integer > 0)

xi Independent variables. (Real)

TIDi Table identification numbers of TABLEH1 entries. (Integer > 0)

h Tw Ta,( )=

84

3. The end of the table is indicated by the existence of “ENDT” in either of the two fields following the last entry. An error is detected if any continuations follow the entry containing the end-of-table flag ENDT.

4. This table is referenced only by PCONV entries that define free convection boundary condition properties.

Defines a tabular function referenced by TABLEHT for convection heat transfer coefficient.

Format:

Example:

Remarks:

1. yi must be listed in ascending order.

2. At least one continuation entry must be present.

3. Any yi-fi pair may be ignored by placing “SKIP” in either of the two fields used for that entry.

4. The end of the table is indicated by the existence of “ENDT” in either of the two fields following the last entry. An error is detected if any continuations follow the entry containing the end-of-table flag ENDT.

5. TABLEH1 is used to input a curve in the form of

TABLEH1 - Heat Transfer Coefficient Table, Form 1

1 2 3 4 5 6 7 8 9 10

TABLEH1 TID

y1 f1 y2 f2 y3 -etc.=

TABLEH1 123

50.0 5.23 75.0 3.76 110.0 0.97 ENDT

Field Contents

TID Table identification number. (Integer > 0)

yi Independent variables. (Real)

fi Dependent variable. (Real)

f f y( )=

85CHAPTER 4Elements

where is input to the table and is returned. The table look-up is performed using linear interpolation within the table and is evaluated at the starting or end point outside the table. No warning messages are issued if table data is input incorrectly.

6. Discontinuities are not recommended and may lead to unstable results.

Specifies the free convection boundary condition properties of a boundary condition surface element used for heat transfer analysis.

See “PCONV -” on page 75 in the preceding section for a detailed descrption.

Theory and Methods The distributed free convection heat flow on a particular grid of a CONV element is computed by

if FORM = 0 and EXPF = 0.0

where hi or = function of and , is the temperature of the grid, and Tai is the temperature of the corresponding ambient node.

For example, if , , and the model is defined by the following Bulk Data entries.

Then the heat transfer coefficient hi is equal to

PCONV - Convection Property Definition

1 2 3 4 5 6 7 8 9 10

PCONV 10 1 101

TABLEHT 101

40.0 1004 60.0 1006 ENDT

TABLEH1 1004

10.0 3.74 20.0 2.14 30.0 0.94 ENDT

TABLEH1 1006

10.0 4.16 20.0 2.96 30.0 1.56 ENDT

y f

Fi h– iAiucntr dln Twi Tai–( )=

Nui Twi Tai Twi

Twi 42.0= Tai 25.0=

0.5 2.14 0.94+( ) 60.0 42.0–( )60.0 40.0–( )

--------------------------------- 0.5+ 2.96 1.56+( ) 42.0 40.0–( )60.0 40.0–( )---------------------------------⋅ ⋅ ⋅ ⋅

86

If the heat transfer coefficient is computed from the Nusselt number (FTYPE=2 in PCONV entry), the distance d from the leading edge of heat transfer is computed as follows.

Where A is the location of GINDIN, B is the centroid of the convection element, and is the unit vector in the direction of boundary-layer flow.

ExampleFree Convection of a Horizontal Cylinder (fconv_axi_2dtable.dat)

This example (see examples folder for input file) demonstrates the application of a 2D table to specify free convection heat transfer coefficient. In this problem, a horizontal cylinder with 0.3048 m in diameter and 0.3 m in length has a heat flux of 7000 W/m2 applied on one end cap. The heat is lost by free convection through the outside surface of the cylinder to the ambient air at 15 oC.

Under laminar condition, the heat transfer coefficient for free convection to air at atmospheric pressure is equal to

Using the above equation, a 2D table is computed with the following data.

Nux

A

B

d

e

d AB= e⋅

e

h 1.32 ∆T D⁄( )0.25 1.32 0.3048⁄( ) Tw Ta–( )0.25 1.77652 Tw Ta–( )0.25= = =

Tw 100°C= Ta 15°C= h 5.3942W m2⁄ °C⋅=

Tw 150°C= Ta 15°C= h 6.0555W m2⁄ °C⋅=

Tw 200°C= Ta 15°C= h 6.5518W m2⁄ °C⋅=

87CHAPTER 4Elements

Input

These data are converted into PCONV, TABLEHT, and TABLEH1 Bulk Data entries listed as follows.

PCONV,1,,,,1,101TABLEHT,101,100.0,1001,150.0,1002,200.0,1003,250.0,1004,300.0,1005,endtTABLEH1,1001,15.0,5.3942,30.0,5.3942,endtTABLEH1,1002,15.0,6.0555,30.0,6.0555,endtTABLEH1,1003,15.0,6.5518,30.0,6.5518,endtTABLEH1,1004,15.0,6.9556,30.0,6.9556,endtTABLEH1,1005,15.0,7.2993,30.0,7.2993,endt

Output

The analysis results using an axisymmetric model with 6-node CTRIAX6 elements are shown below.

Tw 250°C= Ta 15°C= h 6.9556W m2⁄ °C⋅=

Tw 300°C= Ta 15°C= h 7.2993W m2⁄ °C⋅=

88

89CHAPTER 4Elements

4.5 Flux Output Modification for Thermal Analysis

IntroductionThe data recovery of MSC.Nastran Thermal Analysis is enhanced in 2005 r2 by implementing the heat flow output of structural elements. This functionality relates the heat flow output of CHBDYE, CHBDYG, and CHBDYP elements to the structural elements so that users can check the heat balance of the models. The new output also includes convection heat transfer coefficients and side identification numbers to facilitate model checking.

Input The heat flow output of structural elements is requested by the new HTFLOW Case Control command.

Requests heat flow output at selected structural elements.

Format:

Example:

HTFLOW = ALLHTFLOW = 15

HTFLOW - Elemental Heat Flow Output Request

Describer Meaning

PRINT The printer will be the output medium.

NOPRINT Generate, but do not print out, the output.

PUNCH The punch file will be the output medium.

ALL Heat flow for all structural elements will be output.

n Set identification of previously appearing SET command. Only structural elements with identification numbers that appear on this SET command will be included in the heat flow output. (Integer>0)

HTFLOW PRINT, PUNCHNOPRINT

ALL

n

=

90

Remarks:

1. Elemental heat flow output is available for steady state thermal analysis (SOL 101 and SOL 153) and transient thermal analysis (SOL 159).

2. Heat flow is computed from the applied heat loads and the effect of convection and radiation heat transfer on boundary (CHBDYE, CHBDYG, and CHBDYP) elements.

3. See Remarks 6-8 of the descriptions of CHBDYE Bulk Data for the side conventions of solid elements, shell elements, and line elements.

OutputThe output data are grouped by types of structural elements. A sample output is listed below.

The side IDs are consistent with the side conventions of the CHBDYE elements. In the above case, side 1 is the surface of shell elements while sides 2-5 are the four edges of quadrilateral elements.

Theory and MethodsThe formulae used to compute various kinds of heat flow are listed below.

• Free convection if FORM = 0, 10, or 20

if FORM = 1, 11, or 20

• Forced Convection

if FORM = 0, 10, or 20

if FORM = 1, 11, or 21

• Boundary Radiation

H E A T F L O W I N H E X A H E D R O N S O L I D E L E M E N T S ( H E X A ) ELEMENT-ID SIDE HBDY-ID CONV COEFF APPLIED-LOAD CONVECTION RADIATION TOTAL 45 6 451 1.000000E+00 0.000000E+00 -6.892015E+00 -1.159713E+01 -1.848914E+01 5 452 1.000000E+00 0.000000E+00 -7.442470E+00 -1.256259E+01 -2.000506E+01 1 453 1.000000E+00 0.000000E+00 -6.891933E+00 -1.159698E+01 -1.848892E+01 2 454 1.000000E+00 0.000000E+00 -6.846252E+00 -1.151713E+01 -1.836338E+01 46 6 461 1.000000E+00 0.000000E+00 -6.136873E+00 -1.028224E+01 -1.641911E+01 5 462 1.000000E+00 0.000000E+00 -6.341478E+00 -1.063741E+01 -1.697889E+01 1 463 1.000000E+00 0.000000E+00 -6.136881E+00 -1.028225E+01 -1.641913E+01 2 464 1.000000E+00 0.000000E+00 -6.095622E+00 -1.021073E+01 -1.630635E+01 3 465 1.000000E+00 0.000000E+00 -5.932276E+00 -9.927887E+00 -1.586016E+01

F hA–= ucntr dln T Ta–( ) fexpT Ta–( )⋅ ⋅

F hA–= ucntr dln Tfexp

Tafexp

–( )⋅ ⋅

F hA T Ta–( )–=

h coef= Rerexp

Prpexp⋅ ⋅

h coef= Rerexp

Prpexp K

D----⋅⋅ ⋅

F σA–= FAMB ucntr dln ε T4

Ta4

–( )⋅⋅ ⋅ ⋅

91CHAPTER 4Elements

• Enclosure Radiation

• Applied Heat Flux

• Directional Heat Flux

where:

= the heat flow across the selected boundary element

= the convection heat transfer coefficient

= the area associated with the selected boundary element

= the temperature of the control node

= the wall temperature

= the ambient temperature

= the Reynolds number

= the Prandtl number

= the thermal conductivity

= the average diameter or the characteristic length

= the Stefan-Boltzmann constant

= the radiation view factor between the surface and the ambient point

= the emissivity of the selected boundary element

= the grid point temperatures to element temperatures transformation matrix

= the element radiation matrix

= the temperature origin in absolute scale

= the heat flux applied to the selected boundary element.

= the vector of the radiation beam

= the outward surface normal vector

F Gge[ ] Re[ ]{ }TT Tabs+( )4

–=

F q0A= ucntr dln⋅

F α–= e n⋅( ) q0A ucntr dln⋅ ⋅ ⋅

F

h

A

ucntr dln

T

Ta

Re

Pr

K

D

σ

FAMB

ε

Gge[ ]

Re[ ]

Tabs

q0

e

n

92

GuidelinesIf HTFLOW is specified, you may avoid duplicate heat flow output by specifying FLUX=NONE or omitting the FLUX command. This reduces processing time and the sizes of output data for big models.

When CONVM elements are used to model fluid flow, the HTFLOW output will not show the heat flow from forced convection unless there exists dummy CROD elements associated with the CHBDYP elements. In this case, it is recommended to use the original FLUX command to view the heat flow output.

The HTFLOW command only outputs the heat flow of the boundary elements (CHBDYE, CHBDYG, and CHBDYP) that are associated with the surfaces, edges, or points of the selected structural elements. The following table lists the associated boundary elements for each kind of structural elements.

Structural Elements Boundary Elements

Solid elements:CHEXA, CPENTA, and CTETRA.

CHBDYECHBDYG (AREA3, AREA4, AREA6, and AREA8)

Shell elements:CQUAD4, CQUAD8, CTRIA3, and CTRIA6.

CHBDYECHBDYG (AREA3, AREA4, AREA6, and AREA8)CHBDYP (LINE, ELCYL, FTUBE, and TUBE)

Line elements:CROD, CONROD, CBAR, CBEAM, CTUBE, and CBEND.

CHBDYP (LINE, ELCYL, FUTPBE, TUBE, and POINT)

Axisymmetric elements:CTRIAX6

CHBDYECHBDYG (REV)

93CHAPTER 4Elements

ExampleFree Convection of a Cube (fconv_cube.dat)

This example demonstrates the heat flow output of a HEXA element requested by the HTFLOW Case Control command. In this problem, a cube with 0.20 m in each side is maintained at 60 oC and is exposed to air at 10 oC. The thermal conductivity of the cube is equal to 0.02685 , while the heat transfer coefficient between the cube and the air is 9.07 .

The heat flow across each face of the cube can be computed as follows.

Input

SOL 153CENDANALYSIS = HEATTITLE = EXAMPLE HTFLOW REQUESTTEMPERATURE(INITIAL) = 1SUBCASE 1$ Subcase name : Default SUBTITLE=Default NLPARM = 1 SPC = 1 THERMAL=ALL HTFLOW=ALLBEGIN BULKNLPARM 1 0 AUTO 5 25 PW NO .001 1.-7$ Elements and Element Properties for region : solidPSOLID 1 1 0$ Pset: "solid" will be imported as: "psolid.1"CHEXA 1 1 1 2 4 3 5 6 8 7$ Referenced Material Records$ Material Record : alum$ Description of Material : Date: 01-Apr-04 Time: 23:04:54MAT4 1 204. 896. 2707.$ Nodes of the Entire ModelGRID 1 0. 0. 0.GRID 2 .2 0. 0.GRID 3 0. .2 0.GRID 4 .2 .2 0.GRID 5 0. 0. .2GRID 6 .2 0. .2GRID 7 0. .2 .2GRID 8 .2 .2 .2GRID* 999 .256948 .140484* -.026591

W/m °C⋅W/m2 °C⋅

F hA Tw Ta–( )– 9.07–= = 0.04 60 10–( )⋅ ⋅ 18.14W–=

94

$ Loads for Load Case : Default$ Fixed Temperatures of Load Set : fixSPC 1 1 1 60. 2 1 60.SPC 1 3 1 60. 4 1 60.SPC 1 5 1 60. 6 1 60.SPC 1 7 1 60. 8 1 60.$ Fixed Temperatures of Load Set : convSPC 1 1000 1 10.$ Convection to Ambient of Load Set : convPCONV 1 1001 0 0.CONV 100001 1 0 0 1000CONV 100002 1 0 0 1000CONV 100003 1 0 0 1000CONV 100004 1 0 0 1000CONV 100005 1 0 0 1000CONV 100006 1 0 0 1000$ Initial Temperatures from Temperature Load SetsTEMP 1 1 60. 2 60. 3 60.TEMP 1 4 60. 5 60. 6 60.TEMP 1 7 60. 8 60. 1000 10.$ Default Initial TemperatureTEMPD 1 0.$ CHBDYG Surface ElementsCHBDYG 100001 AREA4 1 2 6 5CHBDYG 100002 AREA4 3 7 8 4CHBDYG 100003 AREA4 1 3 4 2CHBDYG 100004 AREA4 2 4 8 6CHBDYG 100005 AREA4 6 8 7 5CHBDYG 100006 AREA4 5 7 3 1$ Free Convection Heat Transfer CoefficientsMAT4 1001 0.02685 9.07$ Scalar PointsSPOINT 1000ENDDATA

The output data from HTFLOW request are listed in the following.

H E A T F L O W I N H E X A H E D R O N S O L I D E L E M E N T S ( H E X A ) ELEMENT-ID SIDE HBDY-ID CONV COEFF APPLIED-LOAD CONVECTION RADIATION TOTAL 1 2 100001 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 4 100002 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 1 100003 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 3 100004 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 6 100005 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 5 100006 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01

95CHAPTER 4Elements

where:

APPLIED-LOAD Heat flow from applied heat flux (QBDY1, QBDY2, QBDY3, and QVECT).

CONVECTION Heat flow from free convection (CONV) and forced convection (CONVM).

RADIATION Heat flow from boundary radiation (RADBC) and enclosure radiation (RADSET).

TOTAL Total heat flow (sum of the above three entities).

96

4.6 Arbitrary Beam Cross Section (Pre-Release)

IntroductionBeam elements have long been a staple in MSC.Nastran. Over the years, the capability of beam elements has grown steadily from a constant cross section of PBAR to a variable cross section of PBEAM. However, you are required to compute the sectional properties in order to utilize BAR or BEAM elements in the analysis. To facilitate ease of use, PBARL and PBEAML were added for popular cross sectional profiles. Nevertheless, you still had to search for modeling alternatives for 1-D structural components with arbitrary cross sectional shapes. For MSC.Nastran 2005 r2, a new user interface for describing cross section shapes for CBAR and CBEAM element types has been developed.

Arbitrary Beam Cross Section modeling is particularly fitting for the automotive industry, keen to be able to easily represent the nonstandard beam profiles commonly used in automotive design, and to use analysis tools to optimize the profile designs themselves.

Subsequent development phases are planned, which will add more advanced features to the Arbitrary Beam Section capability.

BenefitsThe new user interface for describing cross section shapes of CBAR and CBEAM element types provides the ability to:

• More easily model 1D structural components with arbitrary cross-sectional profiles using the MSC.Nastran BAR and BEAM element types for analysis in linear solution sequences.

• Design an optimal cross section profile in the Design Optimization solution sequence, SOL 200, to optimize the overall model performance.

Inputs and OutputsEssentially, the shape of the beam cross section is defined using sets of POINTs as defined on the SET1, or new SET3 Bulk Data entry (subsequent development phases allow section definition using geometric entities - GMCURV). These sets are then referenced by new Bulk Data entries - PBRSECT for the BAR, PBMSECT for the BEAM - used to define the cross section form parameters and reference material properties. The types of section that can be defined include a General Section, Open Profile, and

97CHAPTER 4Elements

Closed Profile, with various parameters required on the PBRSECT or PBMSECT entries to define outer perimeter, inner perimeter, and branch segments where applicable.

Currently for the BEAM element, only a constant cross section beam is supported.

Once all of the bulk data has been read in, equivalent BAR and BEAM elements are created from the data supplied by the PBRSECT and PBMSECT entries. These equivalent element definitions are printed out to the .f06 output file.

Guidelines1. BRP for CP and OP must start or end branching from OUTP. BRP must not

start or end from another BRP.

2. BRP must not branch out from the end of OUTP. This rule covers both CP and OP.

3. For CP and OP, a , where denotes a positive real single precision number, must be present even if the thickness for every segment is separately defined. This thickness will be used for all segments which do not have specific thickness defined for them.

4. When PT=(id1,id2) is utilized to define the thickness of a segment, the id1 and id2 must be next to each other on the SET1 or SET3. A warning message will be issued if this guideline is not observed.

For a design optimization analysis, the PBRSECT and PBMSECT entries are referenced by the design variable property relation entries, DVPREL1. Dimensions that can be taken into the design optimization analysis include:

• Overall Width - input W for PNAME field of DVPREL1. This is available for GS, CP, and OP. Overall width is computed as . Both and

are collected by examining of all POINT entries involved.

• Overall Height - input H for PNAME field of DVPREL1. Also available for GS, CP, and OP. Overall height is computed as . Both and

are collected by examining of all POINT entries involved.

• Segment Thickness - input T or T(id) for PNAME field of DVPREL1. This is available only for CP and OP.

New PBRSECT, PBMSECT, and POINT entries are generated after each design cycle.

The stress recovery points, C, D, E, and F are automatically selected by internal logic that will pick POINTs with extreme coordinates; that is, those closest to the four corners of the rectangle defined by the overall width and height that encloses the cross

T rs= rs

X1max X1min– X1max

X1min X1

X2max X2min– X2max

X2min X2

98

section. If a POINT is on a section defined as a design variable in a design optimization analysis, then the POINT will move as the design variable changes. However, the location of the POINT itself cannot be defined as a design variable.

ExampleZ-Section Beam

Figure 4-5 Z-Section - Uniform Thickness of 0.1

The required Bulk Data entries to define the above section for linear analysis is as follows

1 2 3 4 5 6 7 8 9 10

POINT 1 0.0 0.0

POINT 2 2.0 0.0

POINT 3 2.0 3.9

POINT 4 3.9 3.9

POINT 5 3.9 4.0

POINT 6 1.9 4.0

POINT 7 1.9 0.1

POINT 8 0.0 0.1

$SET3 SID DES ID1 ID2 ID3

SET3 10 POINT 1 THRU 8

4.0

2.0

2.0

99CHAPTER 4Elements

where DES (description) can be POINT, GRID, or ELEMENT.

PBMSECT,2 defines a constant section beam.

The z-section example showing the OP option with thickness definition is as follows:

Further examples are available in the Test Problem Library - zbr3.dat, zbr4.dat zbr5.dat, zbm3.dat, zbm4.dat, zbm5.dat.

$PBRSECT PID MID FORM

PBRSECT 1 1 GS

OUTP=10

where FORM can be: GS - General SectionOP - Open ProfileCP - Closed Profile

$PBMSECT PID MID FORM

PBMSECT 2 1 GS

OUTP=10

1 2 3 4 5 6 7 8 9 10

POINT 11 0.0 0.05

POINT 12 1.95 0.05

POINT 13 1.95 3.95

POINT 14 3.9 3.95

SET3 20 POINT 11 THRU 14

PBRSECT 11 1 OP

OUTP=20, T=0.1, T(2)=[0.1, PT=(12,13)]

PBMSECT 12 1 OP

OUTP=20, T=0.1

100

4.7 Other Element Enhancements

CHBDY FormulationThe calculation of radiation exchange for CHBDY elements is changed. In previous versions of MSC.Nastran, non-physical results for coarse meshes could yield negative temperatures or cause the job to fail to converge--because the temperatures would overshoot near a spatial discontinuity. A new method was developed for MSC.Nastran 2005 r2 that changes the mathematical formula to one that avoids the overshoot. The new method is performed by default, but you may disable the new method by inserting PARAM,RADMOD,NO.

CHEXA Improper GeometryStarting in MSC.Nastran 70.5 there was an error introduced which allowed 8-noded CHEXA elements with improper geometry to pass; when instead this condition should have caused fatal termination of the run and User Fatal Message 7555. This error is now fixed in MSC.Nastran 2005 r2 and will cause fatal termination of the run. The Executive Control statement, GEOMCHECK HEX_DETJ MSGTYPE=WARN," may be specified to avoid fatal termination but this is not recommended.

MSC.Nastran 2005 Release Guide

CHAPTER

5 Optimization

� Topology Optimization

� BIGDOT Optimizer

� Zero Density Material

� High’s Method for Eigenvector Sensitivity and Optimization

102

5.1 Topology Optimization

IntroductionUnlike sizing and shape optimization, topology optimization finds an optimal distribution of material, given the package space, loads, and boundary conditions. These methods have grown rapidly in popularity and application in recent years and topology optimization methods have been discussed in a large number of publications. An overview of topology optimization can be found in a book by Bendsoe and Sigmund [1] and a review article by Rozvany et al [2].

BenefitsTopology optimization can generate more efficient design concepts in the early design stage, especially for load paths. Topology optimization can also be to used to obtain rib patterns and weld distribution patterns. The BIGDOT optimizer is available to solve problems with a large number of design variables and constraints that DOT struggles with due to computer memory requirements and efficiency.

Theory and MethodsMSC.Software has integrated a topology optimization capability into MSC.Nastran 2005 r2 that is based on the increasingly popular density approach to topology optimization. In the density method, Young’s modulus E and density ρ are used as intermediate design variables for each designable finite element. The actual design variable x is the normalized density that links Young’s modulus E and density ρ for designable finite elements using the following relationships

where and are respectively the fully solid Young’s modulus and density. A penalty factor p is introduced to enforce the design variable to be close to a 0-1 solution when p>1.0. The penalty factor p usually takes values between 2 and 4.

The general topology optimization problem available in MSC.Nastran can be stated as follows:

Minimize:

Subject to:

ρ ρ0x=

E E0xp

=

ρ0 E0

f xi( )

103CHAPTER 5Optimization

where represents the j-th constraints and M is the total number of constraints. The constraint specification can be general in that any of the response types currently available in SOL 200 can be used. N is the total number of designable elements. is a small positive number to prevent the stiffness matrix singularity.

Input Topology optimization in MSC.Nastran borrows heavily from the user interface developed for sizing and shape optimization. In particular, the design objective and constraints are defined in an identical manner for topology and sizing/shape optimization. This section discusses the additional bulk data entry that has been provided to ease the creation of the design variables and then discusses other features that have been adapted for topology optimization.

To select a topologically designable region, you need to specify a group of elements. All elements referencing a given property ID are made topologically designable with the Bulk Data entry TOPVAR. Topology design variables are automatically generated with one design variable per designable element.

Format:

TOPVAR Topological Design Variables

1 2 3 4 5 6 7 8 9 10

TOPVAR ID LABEL PTYPE XINIT XLB DELXV POWER PID

Field Contents

ID Unique topology design region identification number. (Integer>0)

LABEL User-supplied name for printing purpose. (Character)

PTYPE Property entry name. Used with PID to identify the elements to be designed. (Character: “PBAR”, “PSHELL”, etc.)

gj xi( ) 0.0≤ j 1 … M, ,=

η xi 1.0≤ ≤ i 1 2 … N, , ,=

gj

η

104

Remarks:

1. The topologically designable element property includes PROD, PBAR, PBARL, PBEND, PBEAM, PBEAML, PSHELL, PSHEAR, PSOLID, and PWELD. Multiple TOPVARs are allowed to design different element types in a single file.

2. All designed element properties must refer to a MAT1 entry; therefore, a PCOMP cannot be used in topology optimization.

3. If DELXV is bank, the default is taken from the specification of DELX parameter on the DOPTPRM entry.

New Responses - Compliance and Fractional Mass

The existing DRESP1 entry has been extended to provide two new response types that are available exclusively for topology optimization. The format for the new responses is shown in Table 5-1 and it is seen that both new response types require only the specification of the response type and no other attributes.

XINIT Initial value. (Real, XLB<XINIT). Typically, XINIT is defined to match the mass target constraint, so the initial design does not have violated constraints. For example, if the mass target is 30%, then it is suggested XINIT=0.3.

XLB Lower bound. (Real, Default = 0.001)

DELXV Fractional change allowed for the design variable during approximate optimization. (Real > 0.0, Default = 0.2 see Remark 3).

POWER A penalty factor used in relation between topology design variables and element Young’s modulus. (Real > 1.0, Default = 3.0). 2.0<POWER<4.0 is suggested.

PID Property entry identifier (Integer > 0)

Field Contents


Remarks:

1. RTYPE=COMP (compliance of structures = ) and FRMASS (mass fraction of designed elements) entries are used for topology optimization only.

2. RTYPE=FRMASS is the mass divided by the mass calculated if all design variables are 1.0. FRMASS is calculated for designed elements only. FRMASS = 1.0 if all design variables are 1.0

The COMP and FRMASS response types are provided to facilitate the specification of the classical topology optimization task of minimizing the compliance of a loaded structure while limiting the mass to some percentage of the maximum allowable amount. In MSC.Nastran’s implementation, these responses can be applied generally so that the COMP response could lead to a constraint and the minimization of FRMASS could be an objective.

New and Modified Design Optimization Parameters (DOPTPRM)

Two new design optimization parameters are added for topology optimization in SOL 200 as shown in Table 5-2. A new parameter TCHECK is used to turn ON/OFF a filtering algorithm to prevent the checkerboard like material distribution. Another parameter TDMIN is introduced to achieve mesh independent solutions, control the size of members in the topology optimized design, and therefore the degree of simplicity in terms of manufacturing considerations.

In addition, a number of existing DOPTPRM parameters have different default values for topology optimization as opposed to Sizing/Shape optimization, as shown in Table 5-3. As described in “BIGDOT Optimizer” on page 114, the BIGDOT optimization algorithm is available for topology optimization problems with many (>2000) designed elements. This is selected by setting DOPTPRM parameter METHOD to 4.

Table 5-1 New Responses for Topology Optimization

Response Type (RTYPE)

Response Attributes

ATTA (Integer>0)

ATTB (Integer>0 or Real>0.0) ATTI (Integer>0)

COMP Remark 1 Blank Blank Blank

FRMASS Remark 1,2

Blank Blank Blank

pTu

106

As a final comment on DOPTPRM parameters, it was necessary to change the definition of the P2 parameter that controls the amount of print that occurs at design cycles specified by P1. For sizing and shape optimization, design variables are printed for any value of P1 = 1 (or if 1 is including in the sum of the options). Since a topology optimization task can easily result in thousands of design variables, this would not be a viable option for most problems. Instead, design variable prints are turned OFF unless P2 value greater than 8 is specified.

OutputP2=1 (default) on Bulk Data entry DOPTPRM does not print topology design variables to minimize optimization output since topology optimization involves in a large number of design variables. P2>8 prints topology design variables.

Output in for the two new responses, compliance and fractional mass, and topology design variables are shown if Figure 5-1. Also in this figure, the design variable history shows the external element ID associated with the internal design variable ID.

Table 5-2 New DOPTPRM Design Optimization Parameters

Name Description, Type, and Default Value

TCHECK Topology Filtering options (integer 0 or 1)

1 Filtering algorithm is on for topology optimization (default)

0 No filtering algorithm

TDMIN Topology minimum member diameter (real > 0.0) in the basic coordinate system. Default =0.0 (i.e., no minimum member size control). This option is applied on 2 and 3 D elements only.

Table 5-3 Default Values for DOPTPRM Design Optimization Parameters

Parameter Sizing/Shape Topology

DESMAX 5 30

CONV1 0.001 1.0E-5

CONVDV 0.001 1.0E-4

DELX 0.5 0.2

DXMIN 0.05 1.0E-5


Figure 5-1 New Output in jobname.f06

PARAM, DESPCH – specifies when the optimized Bulk Data entries are written to the PUNCH file for sizing and shape optimization. In topology optimization, DESPCH is used to specify when the topology optimized element density values are written to the topology element density history file jobname.des. This file can be written in one of two formats. The first format is a MSC.Patran neutral element results file that can be used with a custom template file (.res_tmpl) to display topology results on MSC.Patran. This format is obtained by default. In order to support MSC.Nastran-OptiShape users, this file can also be written in OptiShape Patran Preference format by setting PARAM,DESPCH1=-1. Thus, MSC.Nastran-OptiShape users can display

----- COMPLIANCE RESPONSES ----- ----------------------------------------------------------------------------- INTERNAL DRESP1 RESPONSE LOWER UPPER ID ID LABEL BOUND VALUE BOUND ----------------------------------------------------------------------------- 1 1 COMPL N/A 1.4162E+02 N/A

----- FRACTIONAL MASS RESPONSES ---------------------------------------------------------------------------------- INTERNAL DRESP1 RESPONSE LOWER UPPER ID ID LABEL BOUND VALUE BOUND -----------------------------------------------------------------------------

2 2 FRMASS N/A 3.0000E-01 3.0000E-01

****************************************************************************** S U M M A R Y O F D E S I G N C Y C L E H I S T O R Y ****************************************************************************** DESIGN VARIABLE HISTORY ----------------------------------------------------------------------------- INTERNAL | EXTERNAL | | DV. ID. | ELEMENT ID | LABEL | INITIAL : 1 : 2 ---------------------------------------------------------------------------------------------------------------------------------- 1 | 1 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 2 | 2 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 3 | 3 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 4 | 4 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 5 | 5 | TOPVAR | 3.0000E-01 : 3.6000E-01 : 6 | 6 | TOPVAR | 3.0000E-01 : 3.6000E-01 : 7 | 7 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 8 | 8 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 9 | 9 | TOPVAR | 3.0000E-01 : 2.4000E-01 : 10 | 10 | TOPVAR | 3.0000E-01 : 2.4000E-01 : --------------------------------------------------------------------------

108

and animate SOL 200 topology optimization results using the MSC.Nastran-OptiShape Patran Preference. Figure 5-2 shows and element density history file using the OptiShape Preference format.

Figure 5-2 Element Density History File jobname.des

Guidelines and LimitationsThe quality of the results of a topology optimization task is a strong function of how the problem is posed in MSC.Nastran. This section contains a number of tips that have been developed based on extensive testing of this new capability.

• A new DRESP1=COMP is introduced to define the compliance of structures for topology optimizations. The response is usually used as an objective to maximize structural stiffness in static design problems.

• A new DRESP1=FRMASS is introduced to define the mass fraction of topology designed elements. The DRESP1=WEIGHT is the total weight of all structural and non-structural mass. For topology optimization tasks DRESP1=FRMASS response is recommended to define a mass reduction target in a design constraint.

• The POWER field on the TOPVAR entry has a large influence on the solution of topology optimization problems. A lower POWER often produces a solution that contains large “grey” areas (area with intermediate densities 0.3 – 0.7). A higher value produces more distinct black and white (solid and void) designs. However, near singularities often occur when a high POWER is selected.

/DENSI/ Flag for element density file 1 Design cycle ID

10 1 0.240 External element ID and density value 2 0.240 3 0.240 4 0.240 5 0.360 6 0.360 7 0.240 8 0.240 9 0.240 10 0.240


• A parameter TCHECK on DOPTPRM is used to turn ON/OFF the checkerboard free algorithm. The default of TCHECK=1 activates the filtering algorithm. This default normally results in a better design for general finite element mesh. However, if high order elements and/or a coarser mesh is used, turning off the filtering algorithm may produce a better result.

• The parameter TDMIN is mainly used to control the degree of simplicity in terms of manufacturing considerations. It is common to see some members with smaller size than TDMIN at the final design since the small members have contributions to the objective. Minimum member size is more like quality control than quantity control.

• XINIT on the TOPVAR entry should match the mass target constraint so that the initial design is feasible.

• Maximum design cycle DESMAX=30 (as default) is often required to produce a reasonable result. More design cycles may be required to achieve a clear 0/1 material distribution, particularly when minimum member size control used.

• There are many solutions to a topology optimization, one global and many local minimization. It is not unusual to see different solutions to the same problem with the same discretization by using different optimization solvers or the same optimization solver with different starting values of design variables.

• In a multiple subcase problem, a Case Control command DRSPAN can be used to construct a weighting function via a DRESP2 or DRESP3. For example, a static and normal mode combined problem, the objective can be defined as

where weight1 and weight2 are two weighting factors. is the calculated compliance and is the calculated eigenvalue via DRESP1 definition. and are the initial value of these responses.

• The parameter BAILOUT =0 (default) may cause the topology optimization run to exit if near singularities are detected. Users may increase the value of XLB on TOPVAR to further prevent the singularity or set BAILOUT =-1 to cause the program to continue processing with near singularities.

obj weight1=c1c0-----

⋅ weight2+λ0λ1------

⋅

c1

λ1 c0

λ0

110

• To obtain a rib pattern by topology optimization, a core non-designable shell element thickness must be defined together with two designable above and below the core thicknesses. That is, add two designable elements for each regular element.

• Elements referencing the composite property PCOMP entry cannot be designed.

• Superelements are not supported.

• Topology design variable cannot used together with other type design variables

• Topology design sensitivity is not supported

Numerical problems often occur when solving a topology optimization task. The nature of the problem depends on element type, number of elements, optimization algorithm and so on. One frequent numerical problem is the so-called checkerboard effect. Checkerboard-like material distribution pattern is observed in the topology optimization of continuum, especially when first order finite elements, such as CQUAD4, are employed to analyze structural responses. It has been shown that the Checkerboard-like phenomenon is caused by the finite element formulation. The problem occurs because the checkerboard has an artificially high stiffness compared with a structure with uniform material distribution [1]. The easiest way to decrease the checkerboarding effect is to use higher order elements (such as CQUAD8). This however increase the CPU-time considerably. Another closely related phenomenon is mesh-dependent solutions. It is seen that a more detailed structure is found by increasing the number of elements. The ideas of making a finer finite element mesh is to get a better finite element solution. However, this finer meshing tends to have an increasing number of members with decreasing size. This more detailed topology solution creates a problem from a manufacturing point of view. An overview of the techniques used to avoid the checkerboarding and mesh-dependent solutions can be found in the reference [1]. In SOL 200, filtering algorithms are used to promote a checkerboard-free and mesh independent topology optimized solution.

Topology otimization is powerful tool to generate design concepts in the early design stage. Unfortunately, the topology optimzed designs usually turn out to be infeasible for certain manfacturing processes, such as casting and extrusion. This issue will be addressed in a future MSC.Nastran release.

Example 1 (topex1.dat)


This example leads to a conceptual design of a bicycle frame in a 2D situation by maximizing the stiffness for a given amount of material (70% mass reduction) that (shown in Figure 5-3) satisfies two boundary condition and load cases.

Figure 5-3 Bicycle Frame

Two loading and constraint conditions are assumed corresponding to two scenarios riding the bicycle on sitting and standing positions as shown in the figures below. There are 2442 QUAD4 elements and 2 TRIA3 elements.

112

F

Figure 5-4 E Model of a Bicycle Frame

Input

The input data for this example that is related to topology optimization is listed in Listing 5-1. The result shown in Figure 5-5. is similar to existing bicycle frames.

Listing 5-1 Input File for Example 1

$ Topology Optimization Example 1/ XMY$id msc, topex1 $ v2005 4-Jun-2004 xmySOL 200 $ OPTIMIZATIONCEND$SEALL = ALLSUPER = ALLECHO = NONEset 7 = 20set 9 = 40DESOBJ = 1DESGLB = 1SUBCASE 1 SUBTITLE=LOAD CASE 1 SPC = 2 LOAD = 7


DRSPAN = 7 ANALYSIS = STATICSSUBCASE 2 SUBTITLE=LOAD CASE 2 SPC = 2 LOAD = 9 DRSPAN = 9 ANALYSIS = STATICSBEGIN BULK$TOPVAR, 1 , TSHELL, PSHELL, .3, , , , 1DRESP1 2 FRM FRMASSDRESP1, 20, COMP1, COMP DRESP1, 40, COMP2, COMPDRESP2 1 COMPL SUMDCONSTR 1 2 .3

Output

Figure 5-5 Topology result of a Bicycle Frame

References

1. Bendsoe, M.P. and Sigmund, O. Topology Optimization Theory, Methods, and Applications, Springer, 2003.

2. Rozvany, G.I.N., Bendsoe, M.P., and Kirsch U., Layout Optimization of Structures, Appl. Mech. Rev., 48, 1995, pp.41-119

114

5.2 BIGDOT Optimizer

Introduction BIGDOT is an optimization algorithm that has been developed by VR&D to solve large optimization tasks. A guideline for the DOT optimizer (the workhorse optimizer in SOL 200) is that it can comfortably address problems with several hundred design variables and can be stretched to a few thousand design variables. By contrast, BIGDOT has demonstrated the ability to solve problems with tens of thousands of design variables with the maximum size approaching one million variables. A reference for the BIGDOT algorithm is: Vanderplaats, G., 'Very Large Scale Optimization', presented at the 8th AIAA/USAF/NASA/ISSMO Symposium at Multidisciplinary Analysis and Optimization, Long Beach, CA September 6-8, 2000.

The BIGDOT algorithm is available in MSC.Nastran 2005 r2 and is offered as an additional option as a royalty product that is outside the MasterKey concept. Potential users of this capability should contact their MSC sales representative to get information about the “Topology Optimization” option within MSC.Nastran. The Guidelines and Limitations section of this subchapter discusses how this new option interacts with the standard “Design Optimization” option.

Benefits The primary benefit of including the BIGDOT option is that it enables you to perform topology optimization of real-world structures. As “Topology Optimization” on page 102 indicates, topology optimization entails creating a design variable for each individual element so that one can very quickly exceed to the several thousand design variable practical limitation that is mentioned above for the DOT algorithm.

A second benefit that will be of interest to some users is that it can be applied in sizing applications where the number of design variables is in the thousands and above.

Input BIGDOT is available in MSC.Nastran by specifying METHOD=4 on the DOPTPRM entry. Table 5-4 contains the meanings of the four options for this parameter.


The remaining DOPTPRM parameters that govern the behavior of the optimizer are identical between DOT and BIGDOT so that no additional inputs are required.

OutputThe output from BIGDOT algorithm itself is controlled by existing DOPTPRM parameter IPRINT. There are no other outputs that are affected by BIGDOT.

Guidelines and LimitationsThe BIGDOT algorithm is intended for problems with many design variables. For problems with fewer than one thousand variables, the DOT or ADS algorithms are recommended.

As mentioned in the Introduction to this section, the BIGDOT algorithm is available to users that have purchased the “Topology Optimization” (TO) option for MSC.Nastran. This complements the existing “Design Optimization” (DO) option in the following way:

1. If you have acquired the DO option only, this enables standard shape and sizing optimization and topology optimization with a limited number of design variables. The optimizer can be either DOT or ADS.

2. If you have acquired the TO option only, this enables general topology optimization tasks but does not enable standard shape and sizing optimization. The optimizer is BIGDOT.

3. If you have both DO and TO, the BIGDOT algorithm can then be applied to topology and shape and sizing optimization tasks with a large number of design variables. The optimizer can be BIGDOT or DOT or ADS.

ExampleSee “Example 1” on page 110 for an example of the BIGDOT.

Table 5-4 Meaning of the METHOD Parameter on the DOPTPRM Entry

Value Description

1 Modified Method of Feasible Directions using DOT (default for non-topology optimization problems)

2 Sequential Linear Programming using DOT

3 Sequential Quadratic Programming using DOT

4 BIGDOT (default for topology optimization problems)

116

5.3 Zero Density Material

IntroductionIn SOL 200 you can now specify a zero density on a material entry, and a zero non-structural mass on a property entry to define an element with no mass. Prior to MSC.Nastran 2005 r2 this was not possible, the error ILLEGAL INPUT ERROR (DMKF3D) was issued.

BenefitsPreviously the avoidance to the error mentioned above was to manually add small masses to the model to avoid this limitation. Now you can simply enter a zero density value on the material entry, or a zero non-structural mass on a property entry.


5.4 High’s Method for Eigenvector Sensitivity and Optimization

IntroductionMSC.Nastran SOL 200 already has eigenvector sensitivity and optimization with Nelson’s method or subspace iteration method. It also has eigenvector sensitivity computation with High’s method using an alter package triggered by PARAM,EIGVECDS,1.

The alter package is incorporated into standard MSC.Nastran, so that High’s method can be chosen like Nelson’s method or subspace iteration method as an option for eigenvector sensitivity and optimization.

BenefitsHigh’s method only requires a single decomposition, regardless of the number of design variables and number of eigenvectors, and so it is more efficient.

InputYou can choose between the methods using PARAM,DPHFLG.

Other control parameters:

DPHFLG 0 Nelson’s method (default)

1 Subspace iteration method

2 High’s method, # of modes for iteration = min(2n, n+8, m)

n: the highest constrained mode

m: the number of modes request by EIGR

3 High’s method with all modes requested by EIGR

ITERATE yes do iteration, for improved sensitivity value (Default)

no no iteration, equivalent to Fox’s method

ITMAX maximum number of iteration (Default=10)

TOL tolerance for convergence in iteration (Default=1.0e-4)

LAMBDAS shift factor (Default=0.0)

118

Guidelines

As other methods for eigenvector sensitivity, sparse data recovery needs to be turned off with High’s method. At present, High’s method does not work with super-elements.

For backward compatibility, we still allow PARAM,EIGVECDS,1 to trigger the sensitivity computation with High’s method, though the user need not include the alter package any more.

KORTHO no use mass for Gram Schmidt orthogonalization (Default)

yes use stiffness K for Gram-Schmidt orthogonalization

ITRPRNT no do not print sensitivity for each iteration (Default)

yes print sensitivity for each iteration

ITFPRNT no do not print final sensitivity, leave print to SOL 200.

yes print final sensitivity inside High’s method computation

MDOF no do not reduce DPHI to USET ‘U6’ DOF (Default)

yes reduce DPHI to USET ‘U6’ DOF

MSC.Nastran 2005 Release Guide

CHAPTER

6 Miscellaneous Enhancements

� Large XDB Support

� Enhancements to Modal Damping Processing

� Enhancements to MATMOD Module Option 16

� DIAG 9 - EQUIVX Diagnostic Message

� EXTSEOUT Case Control Command

� K6ROT Drilling Stiffness Removed for Membrane Only Elements

� New Method to Compute Thermal Expansion for Solid Elements

120

6.1 Large XDB Support

IntroductionAs model sizes have steadily increased, MSC.Access database objects have exceeded their entry capacity due to use of a single word access key for keyed objects. Therefore a multi-key storage method has been implemented to support ever increasing database sizes.

Input A new NASTRAN system cell DBCFACT is introduced for creating a XDB file using the new multi-key data format. By default the multi-key method is blocked for legacy/regression purposes. Setting DBCFACT=4 either in the site RC file or as a NASTRAN entry in the file will force the new multi-key access method.

LimitationsMSC.Explore now supports the multi-key access method, please note that this is a pre-release capability.

MSC.ACCESS Application DevelopmentIn anticipation of functional changes to the MSC.ACCESS database organization, changes to the Application Program Interface (API) are being introduced during the basic MSC.Nastran 2005 Release. The changes occur in the user interfaces to the Open routines for the keyed objects. These interfaces are:

Parameters made obsolete during the MSC.Nastran Version 66 releases are being reused and redefined.

An additional parameter has been added.

The user application should now provide a destination variable for the returned information in the arguments to the DBFLOC, OPENR and OPENSQ interfaces. Usage of a constant could result in premature application termination due an attempt to

OPENC Create a Keyed Object

OPENR Read or Update a Keyed Object

OPENSQ Read a Keyed Object using Sequential Methods

DBFLOC Locate a Keyed Object within a Group of Logical Data Bases

121CHAPTER 6Miscellaneous Enhancements

modify protected storage. The definition of the KEY variable in other interfaces has also changed, however until production release of the new functionality along with an update MSC.ACCESS Users Manual, the current application interface will remain functional and provide a correct interfaces to any existing and current 2005 created MSC.ACCESS data bases.

Updated pages for the interfaces from the MSC.ACCESS Users Manual are now provided. The new access key, called BBB-Tree method, will be explained in the next release.

Subroutine Name: DBFLOC

1. Entry Point: DBFLOC

2. Purpose: Locate and open an object among the open database(s)

3. Calling Sequence:

CALL DBFLOC ( NAME, FILNUM, FLEN, FNUM, KEYLEN,IRET )

1. Method: The object is first located, is possible, among the open databases by search from low to high logical data enumeration. Once the first is located, either OPENR or OPENS is used to depending upon its form. The OPENR allows for application updates, while OPENS for sequential objects opens for read-only. Statistics concerning the object size are also returned to the application.

NAME Array-input Dictionary entry of an object name

FILNUM Integer-output Logical file number assigned to the opened object

FLEN Integer-output The length of an instance for a keyed object or the total length in words for a sequential object

FNUM Integer-output The number of entries for keyed object or "1" for sequential objects

KEYLEN Integer-output The key length in words for keyed objects

IRET Integer-output Return code, conforming to OPENR/OPENS error codes, or the additional101 - object format code is neither RECORD or VECTOR102 - dictionary entry could not be located among open database(s)

122

Subroutine Name: OPENC

1. Entry Point: OPENC

2. Purpose: Create new keyed object and return a logical file reference.


CALL OPENC (DBNUM,NAME,WRDREC,FILNUM,KEYLEN,CLSTER,D3,D4,D5,D6,IRET)

4. Method: NAME is checked to determine if it already exists.

The control area is checked to make sure that a new object can be opened and made available for processing.

If both conditions above are satisfied, the buffer management area is cleared and the DAT control area, as described in the DICENT routine description is created. The primary map blocks and the first data area are reserved in the dictionary and stored in the DAT array.

DBNUM Integer-input Logical database number

NAME Array-input Dictionary entry and keyed object name to create

WRDREC Integer-input Number of words per logical record in object

FILNUM Integer-output Logical handle number assigned to the object

KEYLEN Integer-input The number of words in the key

0-> Use Hierarchal Key Method

+n-> Use BBB-Tree Method

CLSTER Integer-input Clustering Method

0 -> Use standard Key clustering algorithm

1-> Re-order keys for optimum entry storage

D3D4D5 D6

Integer-inputCurrently unused. In prior releases, these arguments represented memory addresses for I/O buffer work areas.

IRET Integer-output Return code from the routine

0 -> Normal data block creation

1 -> Requested NAME already existed

2 -> Too many logical files open


The DAT array is copied to both the control area and the primary map block for file management.

The logical file number assigned by the OPENC is returned to the calling application program.

Subroutine Name: OPENR

1. Entry Point: OPENR

2. Purpose: Open existing keyed objects for random access updating and return logical file reference.


CALL OPENR (DBNUM,NAME,WRDREC,FILNUM,KEYLEN,D2,D3,D4,D5,D6,IRET)


NAME Array-input Dictionary entry and object name to update

WRDREC Integer-output Number of words per record in object

FILNUM Integer-output Logical handle number assigned to the object

KEYLEN Integer-output The number of words in the key

0-> Used Hierarchal Method

+n-> Used B-Tree Method

D2D3D4D5D6

Integer-inputCurrently unused. In prior releases, these arguments represented memory addresses for I/O buffer work areas.


0 -> Normal data block open

1 -> Requested NAME does not exist


3 -> Currently unused. In prior releases, it indicated too few buffers allocated.

4 -> Object already open

124

4. Method: DICRDR is used to check the existence of the object NAME and to retrieve its DAT control area.

When the object exists, it is checked for a conflict to another logical file.

When no conflict exists, then a check for available processing space (i.e., less than thirty logical files currently open) is made.

When space is available, the DAT control area is copied to the available control area. The remaining control fields are initialized for object management.

The logical handle number and words per record are returned to the calling application program.

Subroutine Name: OPENSQ

1. Entry Point: OPENSQ

2. Purpose: Open a keyed object for sequential processing and return logical file reference.


CALL OPENSQ (DBNUM,NAME,FILNUM,KEYLEN,IRET)


NAME Array-input Object dictionary entry and object to open

FILNUM Integer-output Logical handle number assigned to object

KEYLEN Integer-output The number of words in the key

0-> Used Hierarchal Method

+n-> Used B-Tree Method


0 -> Normal data block open

1 -> Requested object does not exist


3 -> Unused

4 -> Object already open for update


4. Method: This routine can only be used to open keyed objects for read access. The existence of the object is determined by DICRDR, and its form (keyed) is verified. Control areas are created for logical file operations and initialized with file control data. FILNUM is returned to the calling routine.

126

6.2 Enhancements to Modal Damping ProcessingModal damping may be employed in modal dynamic analysis by specifying an SDAMPING request in Case Control. This request points to a TABDMP1 Bulk Data entry that defines a modal damping table. Enhancements have been made to the processing of this data with a view to providing additional information to the user. Details are described below.

A user warning message is issued if either of the following conditions is satisfied during modal damping processing:

1. The modal damping value is computed as a result of extrapolation.

2. The computed modal damping value is negative.

For any modal damping value that satisfies either of the above conditions, the program lists the cyclic frequency and the corresponding modal damping value and indicates whether this value was computed as a result of interpolation or extrapolation. For the latter case, it also indicates whether the extrapolation was beyond the left end of the table or beyond the right end of the table.

If a modal damping value satisfies both of the conditions 1. and 2. above (that is, the modal damping value is computed as a result of extrapolation and it is negative), the program terminates the job with a user fatal message.

You can prevent the program from terminating the job as above by specifying MDAMPEXT=1 [or SYSTEM(426)=1] on the NASTRAN statement. The user fatal message mentioned above does inform the user of this avoidance scheme.


6.3 Enhancements to MATMOD Module Option 16

IntroductionOption 16 of the MATMOD module was designed to put a matrix into DMIG format in a MATPOOL-type data block as well as to optionally generate DMIG punched output. This option is very useful, particularly in analyses involving part and external superelements. However, its implementation suffers from several deficiencies and inconveniences as explained below.

1. Only G-size matrices are handled. In particular, if the input matrix is square or symmetric, both the rows and columns must be of G-size. If it is a rectangular matrix, the rows must be of G-size, while the columns are regarded as just sequential entities.

2. The rows and columns of the input matrix must be in external sort. This is a particularly inconvenient requirement since it requires re-arrangement of its rows and columns that are normally in internal sort. This requirement forces the use of Option 9 of the MATGEN module to generate a transformation matrix to convert from internal sort to external sort and then employing this transformation matrix to perform the required transformation of the desired matrix before it can be used as input to the MATMOD module.

3. The name of the matrix in the DMIG output is the same as the name of the data block containing the input matrix. There is no way to give an arbitrary name to the matrix in the DMIG output.

4. Even if only the DMIG punched output is desired, the MATPOOL-type output data block still has to be generated even though it may never be used thereafter.

5. Each call to MATMOD Option 16 generates a separate MATPOOL-type output data block. This can result in a large number of such data blocks when many calls to MATMOD Option 16 are involved. There is no way to get a single concatenated output data block from multiple calls to MATMOD Option 16.

Major enhancements have been made to Option 16 of the MATMOD module in order to overcome the above deficiencies and inconveniences. These enhancements utilize an additional input data block and several additional parameters to accomplish their purpose. These enhancements are explained below.

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1. The size of the input matrix is no longer restricted to G-size. Instead, any size corresponding to any valid displacement set of the User Set (USET) table is allowed. Also, for the first time, Option 16 can handle rectangular matrices wherein the columns correspond to a displacement set and are not necessarily regarded as sequential entities. This allows Option 16 to handle the more general case of rectangular matrices wherein the rows and columns correspond to different displacement sets.

2. The rows and columns of the input matrix need not be in external sort. They can be in internal sort which is their normal arrangement.

3. The name of the matrix in the DMIG output need not be the same as the name of the data block containing the input matrix. An arbitrary name can be specified for the matrix in the DMIG output.

4. The MATPOOL-type output data block need not be generated if only the DMIG punched output is desired.

5. By using the “APPEND” option on a FILE statement, it is possible to get a single concatenated MATPOOL-type output data block from multiple calls to MATMOD Option 16.

InputPut matrix into DMIG format in a MATPOOL-type data block and/or generate DMIG punched output.

Format:

Input Data Blocks:

Output Data Block:

MATMOD MATIN,EQEXIN,USET,,,/MATPOOLX,/16/PNDMIG/SORTFLG/TYPOUT////////CCHAR/DMIGNAME/ROWSETNM/COLSETNM $

MATIN Matrix to be converted to DMIG format. (Real or complex). See Remark 1.

EQEXIN EXEQXIN table from module GP1. See Remark 7.

USET USET table from module GP4 or GPSP. See Remark 8.

MATPOOLX MATPOOL-type table data block containing MATIN in DMIG format. See Remarks 9. and 10.


Parameters:

Remarks:

1. The form of MATIN is either 1 (square), 6 (symmetric) or 2 (rectangular). If not, a warning message is issued and MATPOOLX is not generated.

PNDMIG Input-integer-default=0. If PNDMIG is non-zero, then DMIG punched output will be generated. See Remarks 9. and 10.

SORTFLG Input-integer-default=0. The default assumes that the rows (and columns, if applicable) of MATIN are in external sort. If SORTFLG is non-zero, then it is assumed that they are in internal sort. See Remark 2.

TYPOUT Input-integer-default=0. The default sets the DMIG precision to machine precision. The default maybe overridden by specifying the following:

1 Real single precision format

2 Real double precision format

3 Complex single precision format

4 Complex double precision format

CCHAR Input-character-default=blank. Continuation characters to be used for DMIG punched output. Only the first two characters of the non-blank mnemonic are used for the continuation string. See Remark 3.

DMIGNAME Input-character-default=blank. The default will cause the name of the MATIN input data block to the used for the matrix name in the DMIG output. A non-blank name will cause that specified name to be used for the matrix name in the DMIG output.

ROWSETNM Input-character-default=blank. The default assumes that the rows of MATIN are of G-size. Any non-blank mnemonic specifies the displacement set for the rows. See Remarks 4., 5. and 6.

COLSETNM Input-character-default=blank. If the form of MATIN is 1 (square) or 6 (symmetric), then the default assumes that the displacement set for the columns is the same as that of the rows. If the form of MATIN is 2 (rectangular), then the default (or a mnemonic of ‘H’) assumes that the columns do not represent any displacement set, but just sequential entities. Any non-blank mnemonic other than ‘H’ specifies the displacement set for the columns. See Remarks 4., 5. and 6.

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2. If the default value of 0 for SORTFLG is used, the rows of MATIN must be of G-size. If MATIN is square or symmetric, its columns must also be of G-size. Further, the default value of 0 for SORTFLG also assumes that the rows and columns of MATIN are in external sort. In order to accomplish this, it is necessary to first generate a transformation matrix via the MATGEN module Option 9 and then employ this matrix to transform the rows and columns of MATIN from internal sort to external sort. (This is illustrated in the Example shown below.)

3. If non-blank continuation characters are specified for CCHAR, then a maximum of 99,999 DMIG entries can be generated for any single matrix. If this maximum number is exceeded, the program terminates the job with a fatal error.

4. The program checks to ensure that the number of rows and columns of MATIN correspond to the displacement sets specified (or implied) by ROWSETNM and COLSETNM. If this condition is not satisfied, the program issues a warning message and proceeds without generating any output from this call to the MATMOD module.

5. If the form of MATIN is either 1 (square) or 6 (symmetric), then the IFO field on the generated DMIG entry is set to 1 or 6. If the form is 2 (rectangular), then IFO is set to 2 if a displacement set is specified (or implied) for COLSETNM. Otherwise, IFO is set to 9. (If the form is 6, only the terms in one triangle are output. The MTRXIN module, which converts DMIG data in MATPOOL-type data blocks into matrices, fills in the other triangle for symmetric matrices.)

6. The rows of the DMIG entry are always labeled with the appropriate grid/scalar IDs and component numbers. If a displacement set is specified (or implied) for COLSETNM, then the columns of the DMIG entry are also labeled with the appropriate grid/scalar IDs and component numbers. Otherwise, the columns of the DMIG entry are labeled sequentially, starting with unity.

7. The EQEXIN input data block may not be purged.

8. The USET input data block may be purged if (a) the default value of 0 is used for SORTFLG or (b) the displacement set specified (or implied) by ROWSETNM is ‘G’ and the displacement set specified (or implied) by COLSETNM is either ‘G’ or the columns are just sequential entities.

9. The MATPOOLX output data block may be purged if PNDMIG is specified as non-zero and only the DMIG punched output is desired.


10. By employing the “APPEND” option on a DMAP FILE statement, a single concatenated MATPOOLX output data block may be generated from multiple calls to MATMOD Option 16. See the following Example 2.

GuidelinesAs indicated earlier, the above enhancements are accomplished by using one additional input data block and several additional parameters. The new usage of Option 16 is as follows:

Input data block USET and the parameters P3, P13, P14 and P15 represent additions as part of the enhancements. The default values for these additional parameters have been chosen such that legacy files employing the old usage of Option 16 will continue to give the same results as before.

Example

The examples below illustrate the power of the new Option 16 and clearly show that the enhanced features result in much simpler and more efficient DMAP programs.

Example 1:

Generate DMIG punched output for the boundary stiffness matrix KAA, the boundary load matrix PA and the matrix GMN (representing the MPC/rigid element equations) for an external superelement. The KAA DMIG entry is to be named KAAEXTSE, the PA DMIG entry is to be named PAEXTSE and the GMN DMIG entry is to be named GMNEXTSE.

The DMAP shown below illustrates the usage of Option 16 using input matrices in internal sort (capability available in MSC.Nastran 2005 r2 and subsequent releases) as well as using input matrices in external sort (only usage possible in pre-MSC.Nastran 2005 r2 releases). You can see that the DMAP for the former case is much simpler and more efficient than for the latter case.

Note that if the internal and external sorts are different, the DMIG output resulting from the two scenarios shown below will appear to be different. This is because the matrix elements will be output in different order, but their values will be the same. The DMIG output from the two scenarios will yield identical matrices if they are used in turn by the MTRXIN module to re-generate the matrices.

MATMOD MATRIX,EQEXIN,USET,,,/MATPOOLX,/16/P2/P3/P4////////P12/P13/P14/P15 $

132

DMAP using input matrices in internal sort (MSC.Nastran 2005 r2 and subsequent releases).

DMAP using input matrices in external sort (pre-MSC.Nastran 2005 r2 releases).

Example 2:

Generate a single MATPOOL-type data block containing the DMIG output for the boundary stiffness matrix KAA, the boundary mass matrix MAA, the boundary viscous damping matrix BAA and the boundary structural damping matrix K4AA for an external superelement, with the corresponding DMIG entry names of KAAXSE, MAAXSE, BAAXSE and K4AAXSE, respectively.

TYPE PARM,,I,N,PUNCHFLG=1 $ GENERATE DMIG PUNCHED OUTPUTTYPE PARM,,I,N,SORTFLG=1 $ INPUT MATRICES ARE IN INTERNAL SORTMATMOD KAA,EQEXIN,USET,,,/,/16/PUNCHFLG/SORTFLG//////////

’KAAEXTSE’/’A’ $MATMOD PA,EQEXIN,USET,,,/,/16/PUNCHFLG/SORTFLG//////////

’PAEXTSE’/’A’ $MATMOD GMN,EQEXIN,USET,,,/,/16/PUNCHFLG/SORTFLG//////////

’GMNEXTSE’/’M’/’N’ $

TYPE PARM,,I,N,PUNCHFLG=1 $ GENERATE DMIG PUNCHED OUTPUT$ EXPAND BOUNDARY MATRICES TO G-SIZEUMERGE1 USET,KAA,,,/KAAGG/’G’/’A’ $ EXPAND ROWS AND COLUMNSUMERGE1 USET,PA,,,/PAG/’G’/’A’//1 $ EXPAND ROWSUMERGE1 USET,GMN,,,/GMNGN/’G’/’M’//1 $ EXPAND ROWSUMERGE1 USET,GMNGN,,,/GMNGG/’G’/’N’//2 $ EXPAND COLUMNS$ GET G-SIZEPARAML USET//’TRAILER’/2/S,N,GSIZE $$ GENERATE MATRIX TO TRANSFORM FROM INTERNAL SORT$ TO EXTERNAL SORTMATGEN EQEXIN/INTEXT/9/0/GSIZE $$ TRANSFORM MATRICES FROM INTERNAL SORT TO$ EXTERNAL SORT WITH APPROPRIATE DESIRED NAMESMPYAD INTEXT,KAAGG,/KAAGGX/1 $MPYAD KAAGGX,INTEXT,/KAAEXTSE $MODTRL KAAEXTSE////6 $MPYAD INTEXT,PAG,/PAEXTSE/1 $MPYAD INTEXT,GMNGG,/GMNGGX/1 $MPYAD GMNGGX,INTEXT,/GMNEXTSE $$GENERATE DMIG FORMATMATMOD KAAEXTSE,EQEXIN,,,,/MATPOOLK,/16/PUNCHFLGMATMOD PAEXTSE,EQEXIN,,,,/MATPOOLP,/16/PUNCHFLGMATMOD GMNEXTSE,EQEXIN,,,,/MATPOOLG,/16/PUNCHFLG$ MATPPOLK, MATPPOLP AND MATPOOLG OUTPUT DATA BLOCKS$ HAVE TO BE GENERATED ABOVE EVEN THOUGH ONLY DMIG$ PUNCHED OUTPUT IS DESIRED


The DMAP following illustrates the usage of Option 16 to accomplish the above objective in MSC.Nastran 2005 r2 and subsequent releases. Note that this objective could not be met in pre-MSC.Nastran 2005 r2 releases.

DMAP for MSC.Nastran 2005 r2 (and subsequent releases).

FILE MATPOOLA = APPEND $ PERMIT CONCATENATED OUTPUTTYPE PARM,,I,N,SORTFLG=1 $ INPUT MATRICES ARE IN INTERNAL SORTMATMOD KAA,EQEXIN,USET,,,/MATPOOLA,/16//SORTFLG//////////

’KAAXSE’/’A’ $MATMOD MAA,EQEXIN,USET,,,/MATPOOLA,/16//SORTFLG//////////

’MAAXSE’/’A’ $MATMOD BAA,EQEXIN,USET,,,/MATPOOLA,/16//SORTFLG//////////

’BAAXSE’/’A’ $MATMOD K4AA,EQEXIN,USET,,,/MATPOOLA,/16//SORTFLG//////////MATMOD ’K4AAXSE’/’A’ $

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6.4 DIAG 9 - EQUIVX Diagnostic MessageDIAG 9 prints a new diagnostic message in the f04 file when the EQUIVX module has both the primary and secondary data block are not purged. DIAG 9 augments the messages provided by DIAGs 8 and 15 and should be useful to DMAP programmers and debuggers. In the following f04 file excerpt, it shows how KJJZ generated in the EMA module "becomes" KGG.

7:04:09 0:04 76.0 0.0 0.4 0.0 SEMG 145 EMA BEGN*8** Module DMAP Matrix Cols Rows F T NzWds Density BlockT StrL NbrStr EMA 145 KJJZ 18 18 6 2 12 8.64198D-02 3 1 14 7:04:09 0:04 76.0 0.0 0.4 0.0 SEMG 163 (S)XMTRXIN BEGN 7:04:09 0:04 76.0 0.0 0.4 0.0 SEMG 166 MGEN BEGN 7:04:09 0:04 76.0 0.0 0.4 0.0 SEMG 184 (S)SEMG1 BEGN*9** EQUIVX 25 KJJX equivalenced from KJJZ *9***9** EQUIVX 27 KJJ equivalenced from KJJX *9** 7:04:09 0:04 76.0 0.0 0.4 0.0 SEMG 186 PROJVER BEGN 7:04:09 0:04 76.0 0.0 0.4 0.0 PHASE1A 83 MSGHAN BEGN 7:04:09 0:04 76.0 0.0 0.4 0.0 PHASE1A 84 MSGHAN BEGN 7:04:09 0:04 76.0 0.0 0.4 0.0 PHASE1A 85 (S)SESUM BEGN*9** EQUIVX 90 KGG equivalenced from KJJ *9**


6.5 EXTSEOUT Case Control CommandEXTSEOUT Case Control command usage has been enhanced:

• In SOL 101: The fixed-boundary displacements due to interior loads are now included in the assembly run results.

• For EXTSEOUT(DMIGPCH): Interior data recovery for the superelements may now be computed in the assembly run.

136

6.6 K6ROT Drilling Stiffness Removed for Membrane Only Elements K6ROT stiffness was modified in MSC.Nastran 2004 (see the MSC.Nastran 2004 Release Guide, Section 5.12, New K6ROT Default). The drilling stiffness is useful for curved models, but it is undesirable for membrane-only (or plane strain) models. The drilling stiffness introduced by K6ROT is particularly undesirable when membrane-only elements are used to 'skin' a solid element model, as rotation degrees of freedom are added to a model which uses only translation degrees of freedom.

In MSC.Nastran 2005 r2 if PARAM,K6ROT is greater than zero (the default value), it will be used only by elements that have both membrane and bending stiffness.


6.7 New Method to Compute Thermal Expansion for Solid Elements The purpose of this modification is to increase stress accuracy for solid elements of low stress whenever thermal expansion is specified. When thermal expansion is requested, MSC.Nastran computes loads which cause the structure to deform. For stress data recovery the thermal expansion is subtracted from the element distortion before computing stresses. The limitations due to element theory (shape functions) often cause large stresses to be computed when the value should be near zero, which could be cause for concern, since they may look significant.

A solid element model with a temperature increase which is linear in (x, y, z), and has non-redundant constraints, should be stress free. The modified method will give exact displacements and computed zero stresses for the free expansion case. This is implemented for h-element HEXA, PENTA, and TETRA elements, with or without midside nodes, for all integration options on the PSOLID record.

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MSC.Nastran 2005 Release Guide14

CHAPTER

7 DMAP Module Changes

� Summary of DMAP Module Changes from MSC.Nastran 2005 to MSC.Nastran 2005 r2

140

7.1 Summary of DMAP Module Changes from MSC.Nastran 2005 to MSC.Nastran 2005 r2This chapter summarizes DMAP module changes from MSC.Nastran 2005 to MSC.Nastran 2005 r2 which could affect your DMAP alters and solution sequences. This information is intended to help you convert your MSC.Nastran 2005 DMAP alters and solution sequences to run in MSC.Nastran 2005 r2.

The format of the following module has been modified in MSC.Nastran 2005 r2 such that the MSC.Nastran 2005 format is not upward compatible with MSC.Nastran 2005 r2 and/or their behavior is not upward compatible. The changes are described in the next section.

The following is a list of existing modules with new features or fixes which require format changes in MSC.Nastran 2005 r2 but their MSC.Nastran 2005 formats are considered upward compatible in MSC.Nastran 2005 r2. The changes are described in the next section.

The following is a list of new modules in MSC.Nastran 2005 r2. They are not documented here but will be documented in the "MSC.Nastran 2006 DMAP Programmers' Guide".

DMAP Module Changes

This section shows the changes for DMAP module instructions which were changed from MSC.Nastran 2005 to 2005 r2. The module change descriptions are presented as differences with respect to the "MSC.Nastran 2005 DMAP Programmers' Guide" which is available on the "Combined Documentation 2005" CD. The change descriptions below includes the MSC.Nastran 2005 r2 format of the module with changes in bold text. Any new or changed data blocks and parameters are also described below the format.

AELOOP

AEMODEL APPEND DOM9 DOPR1 DSAN GKAM GP3

GPSTR2 GUSTLDW ILMP1 MAKMON MATMOD MATMOD MPYAD

NLSOLV OUTPUT2 READ SEP1X SEP2X SSG1 VIEWP

DMPCASE EXPORTLD FBODYLD MDISUTIL MPPTRAN MRGCSTM PNCHGRP

PNMKGRP

141CHAPTER 7DMAP Module Changes

AELOOP

Format:

Input Data Block:

Output Data Block:

Parameters:

AEMODEL

Format:

Input Data Block:

Output Data Block:

AELOOP CASECC,EDT,CCPOS/CASEA,ccpos1/S,N,NSKIP/S,N,LPFLG/S,N,MFLG/S,N,MACH/S,N,Q/S,N,AEQRATIO/S,N,AECONFIG/S,N,SYMXY/S,N,SYMXZ/CRTPOS/S,N,RCONFIG/MASSETID $

CCPOS Table of Case Control record locations.

CCPOS1 Table of Case Control record locations.

CRTPOS Input-integer-default=0. CCPOS1 creation flag.

>0 Create CCPOS1

<0 Do not create CCPOS1

RCONFIG Output-character-no default. Configuration name for rigid aero.

MASSETID Input-integer-default=0. Identification number of the MASSSET CaseControl command.

AEMODEL CASECC,EDT,CCPOS/CCPOS1S,N,NSKIP/S,N,LPFLG/S,N,AECONFIG/S,N,SYMXY/S,N,SYMXZ/CRTPOS $

CCPOS Table of Case Control record locations.

CCPOS1 Table of Case Control record locations.

142

Parameter:

APPEND

Format:

[rename CHAR to CHAR1]

Parameter:

[rename CHAR to CHAR1]

DOM9

Format:

Input Data Blocks:

CRTPOS Input-integer-default=0. CCPOS1 creation flag.

>0 Create CCPOS1

<=0 Do not create CCPOS1

APPEND IN1,IN2/OUT/IOPT/NULL1/NULL2/REAL/REALD/CMPX/CMPXD/CHAR1/CHAR2 $

CHAR2 Input-character-default='XXXXXXXX'. Character value in the same record as CHAR1 and following CHAR1.

DOM9 XINIT,DESTAB,CONSBL*,DPLDXI*,XZ,DXDXI,DPLDXT*,DEQATN,DEQIND,DXDXIT,PLIST2*,OPTPRMG,R1VALRG,RSP2RG,R1TABRG,CNTABRG,DSCMG,DVPTAB*,PROPI*,CONS1T,OBJTBG,COORDO,CON,SHPVEC,DCLDXT,TABDEQ,EPTTAB*,DBMLIB,BCON0,BCONXI,BCONXT,DNODEL,RR2IDR,RESP3RG,RQATABRG,TOPTAB,PBRMSD,TOPMC,TOPMC2,TMINIT,TOPELE,TPRELE/XO,CVALO,R1VALO,R2VALO,PROPO,R3VALO,tminit1/OBJIN/S,N,OBJOUT/PROTYP/EIGNFREQ/PROPTN/UNUSED6/UNUSED7/UNUSED8/UNUSED9/UNUSED10/UNUSED11/UNUSED12/UNUSED13/UNUSED14 $

TOPMC2 Topology member size control table for manufacturing constraints

TMINIT Table of initial design variable values for topology with manufacturing constraints


Output Data Block:

DOPR1

Format:

Input Data Blocks:

Output Data Blocks:

TOPOLE Table of topology pole parameters (used only for topology manufacturing constraints)

TPRELE Table of topology pole vs. element ids (used only for topology manufacturing constraints)

TMINIT1 Updated table of initial design variable values for topology with manufacturing constraints

DOPR1 EDOM,EPT,DEQATN,DEQIND,GEOM2,MPT,EDT,CASECC,TOPTAB0,TOPELE,PBRMS,BGPDT,ECT,GPECT,velem,cstm/DESTAB,XZ,DXDXI,DTB,DVPTAB*,EPTTAB*,CONSBL*,DPLDXI*,PLIST2*,XINIT,PRO*PI*,DSCREN,DTOS2J*,OPTPRM,CONS1T,DBMLIB,BCON0,BCONXI,DMATCK,DISTAB,TOPTAB,PBRMSD,NWEDOM,NWCASE,TOPMC,TOPMC2,TMINIT,TOPELE,TPRELE/S,N,MODEPT/S,N,MODGEOM2/S,N,MODMPT/DPEPS/S,N,PROTYP/S,N,DISVAR/S,N,NRANVAR $

CSTM Table of coordinate system transformation matrices.

VELEM Table of element lengths, areas, and volumes.

TOPMC2 Topology member size control table for manufacturing constraints

TMINIT Table of initial design variable values for topology with manufacturing constraints

TOPOLE Table of topology pole parameters (used only for topology manufacturing constraints)

TPRELE Table of topology pole vs. element ids (used only for topology manufacturing constraints)

144

DSAN

Format:

Input Data Blocks:

GKAM

Format:

Output Data Block:

GP3

Format:

Input Data Block:

DSAN TABEV2,ETT,est,mpt/DSPT1,ETTDV $

EST Element summary table.

MPT Table of Bulk Data entry images related to material properties.

GKAM USMEMF/ETD,PHA,MI,LAMA,DIT,M2DD,B2DD,K2DD,CASECC,LAMMAT,MHH,BHH,KHH,PHDH,MODSELT,MODSELV,LAMASEL,BMODAL/NOUE/LMODES/LFREQ/HFREQ/UNUSED5/UNUSED6/UNUSED7/S,N,NONCUP/S,N,FMODE/KDAMP/FLUID/UNUSED12/APP $

BMODAL Matrix of modal damping values from selected TABDMP1 Bulk Data entry in DIT.

GP3 GEOM3,BGPDT,GEOM2,EDT,UGH,ESTH,BGPDTH,CASEHEAT,MPT,PG*/SLT,ETT/S,N,NOLOAD/S,N,NOGRAV/S,N,NOTEMP $

PG* Family of external load matrices qualified by LOADID or FBLID


GPSTR2

Format:

Parameter:

GUSTLDW

Format:

Parameter:

GPSTR2 CASECC,EGPSF,BGPDT,OES1,OESNLXR/OGS1,EGPSTR/S,N,NOOGS1/S,N,NOEGPSTR/APP/NLSTRAIN/GPSOPT $

GPSOPT Input-integer-default=0. Option bits numbered right to left

Bit Description

1 Requests that direct stresses/strains for volume always be output. (This is an MSC.ADAMS MNF requirement).

2 Requests that principal stresses/strains for volume always be output

3 Set device code bit in OGS1's Id record to indicate plot only for direct stress/strain for volume

4 Set device code bit in OGS1's Id record to indicate plot only for principal stress/strain for volume

GUSTLDW EDT,AERO,CSTMA,MKLIST,AEBGPDT*,SKJ,LAJJT,UAJJT/QKGUST*/GUST2ID/S,N,QKGUST1 $

QKGUSTL Output-logical-default=FALSE. QKGUST* creation flag.

TRUE : QKGUST* was created

FALSE: QKGUST* was not created

146

ILMP1

Format:

Input Data Block:

MAKMON

Format:

Parameter:

MATMOD

MATMOD Option 16

See “Enhancements to MATMOD Module Option 16” on page 127.

ILMP1 EST,BGPDT,EDT,EDT0/CASEUNIT,UNITDISP,UNITPV,EDTM/S,N,NCOLUNIT $

EDT0 Table of archived set of MONPNT2 records to be merged into EDTM.

MAKMON EDT, , /

, MONDISP , MONGRP / MKERRCHK $

MKERRCHK Input-logical-default=FALSE. Error check flag.

TRUE: Perform check

FALSE: Do not perform check

AEROCOMP

STRUCOMP

AEROCOMP

AEMONPT

MONITOR


MODGM2

Format:

Parameters:

MPYAD

Format:

Parameters:

MODGM2 EPT,GEOM2,GEOM1,GEOM4,BGPDT,CSTM,MPT/GEOM2X,GEOM1X,GEOM2DCW,EPTX,MPTX/S,N,ACFLAG/OSWPPT/OSWELM/S,N,NSWPPT/S,N,NSWELM/S,N,SWEXIST/S,N,NOGOMGM2/S,N,RGDEXIST/RIGID/ORIGID/S,N,NLRIGID/LMFACT/PENFN/NONLNR/CWRANDEL/CWDIAGP/CFRANDEL/CFDIAGP/S,N,NOEPT/S,N,NOMPT/SOFFSET/csrandel/csdiagp $

CSRANDEL Input-real-default=0.0. Rate (percentage) at which CWSEAM elements are removed from the model. Usually input by user parameter.

CSDIAGP Input-character-default=' '. Flag, if YES, to write diagnostics of CWSEAM element deletion. Usually input by user parameter

MPYAD A,B,C/X/T/SIGNAB/SIGNC/PREC/FORM/DODMP/DMPYIN/DMPYOUT $

DODMP Input-integer-default=0. Distributed memory parallel flag.

0: compute in serial (default)

1: compute in distributed memory parallel method 1

2: compute in distributed memory parallel method 1

DMPYIN Input-logical-default=TRUE. For DODMP>0, broadcast flag to input matrices from master processor to slave processor(s).

DMPYOUT Input-logical-default=TRUE. For DODMP>0, broadcast flag to X matrix from slave processor(s) to master processor.

148

NLSOLV

Format:

Input Data Blocks:

Parameter:

NLSOLV CASEXX ,PPN ,YS ,ELDATA ,KELMNL ,

KPP ,GMNE ,MPT ,DIT ,KFEFE ,

DLT1 ,CSTM ,BGPDT ,SIL ,USETD ,

BFEFE ,MFEFE ,NLFT ,RDEST ,RECM ,

BPP ,GPSNT ,DITID ,DEQIND ,DEQATN ,

MPP ,MBSP ,MBFEP ,MMP ,GMFE ,

GMS ,RSPTQS ,RMPTQM ,GEOM4 ,KTPP ,

YVELO ,YACCE ,GPTT1 EPT ,TMLDS ,

ROTORT ,BGPP* ,KCVPP* /

UPN ,IFS ,ESTNLH ,IFP ,OESNL ,

PPL ,TEL ,MUPVNL ,MESTNL ,BTOPCNV ,

BTOPSTF ,OESNLB1 ,FMV ,QPV ,DUPV ,

RPV ,GEOM4CN ,KFRIC ,UNUSED1 ,UNUSED2 ,

UNUSED3 ,UNUSED4 ,LTF ,UTF ,PNLT ,

IFST ,PPLT ,UPNT ,FMVT ,EST0 ,

MESTNL0 ,UPNL0 /

KRATIO /S,N,CONV/S,N,STIME/S,N,NEWS/S,N,NEWK/

S,N,OLDDT /S,N,NSTEP/LGDISP/S,N,CONSEC/S,N,ITERID/

ITIME0 /S,N,KTIME/S,N,LASTUP/S,N,NOGONL/S,N,NBIS/

MAXLP /TSTATIC /LANGLE /NDAMP /TABS /

SIGMA /NLR /S,N,ADPCON/PBCONT/S,N,NBCONT/

MARC3X /S,N,MNEWK/S,N,NLOFLAG/TANALY/FKSYMFAC/

RSTFLG /NLPACK /GPFRC /GNLSTN /MSCHG /

K6ROT /WTMASS $

EPT Table of Bulk Data entry images related to element properties.

TMLD Table of loads for nonlinear transient analysis.

ROTORT Table of rotordynamics user input for transient analysis.

BGPP* Family of coriolis matrices - p-set.

KCVPP* Family of gyroscopic matrices - p-set.

WTMASS Input-real-default=1.0. Scale factor on structural mass matrix.


OUTPUT2

Format:

Parameter:

READ

Format:

Parameter:

ROTOR

Format:

OUTPUT2 DB1,DB2,DB3,DB4,DB5,CASECC//ITAPE/IUNIT/LABL/MAXR/NDDLNAM1/NDDLNAM2/NDDLNAM3/NDDLNAM4/NDDLNAM5/HNAME1/HNAME2/HNAME3/HNAME4/HNAME5/PROCID $

PROCID Input-integer-default=1. Processor ID which is authorized to write to IUNIT. Used only in distributed memory parallel (DMP) runs.

READ KAA,MAA,MR,DAR,DYNAMIC,USET,CASECC,

PARTVEC,SIL, , ,

, /

LAMA,PHA,MI,OEIGS,LAMMAT,OUTVEC/ FORMAT/S,N,NEIGV/NSKIP/FLUID/SETNAME/SID/METH/ F1/F2/NE/ND/MSGLVL/MAXSET/SHFSCL/NORM/PRTSUM/MAXRATIO/MDLGDEF $

MDLGDEF Input-integer-default=8000. Minimum number of degrees-of-freedom which activates special ACMS DECOMP/FBS method in READ module for buckling problems (FORMAT<>"MODES").

ROTOR BGPDT,DYNAMIC,DIT,CSTM,VDA/ROTOR,ROTORT/CONFAC/APP $

VACOMP

SPCCOL INVEC

EQMAP LLL

VFO1

EQEXIN

GAPAR

150

Input Data Block:

SEP1X

The format has not changed but the SEP1XOVR parameter is now an output parameter which must be passed into SEP2X. Also additional options are available in SEP1XOVR.

Parameter:

Additional bit options for SEP1XOVR.

Remark:

3. The SEP1X module checks the residual part and bit 8 on the SEP1XOVR parameter to determine a-set membership at the residual level. The default action is to place all upstream q-set in the a-set in the residual when any ASETi, BSETi, CSETi, QSETi or OMITi records are detected in the residual based upon user specifications. Otherwise, SEP1X changes the SEP1XOVR parameter to indicate to SEP2X not to generate ASET records for the q-set boundary degrees-of-freedom and then let the left-over logic of GP4 assign to a-set or o-set. Note that the user can set bit 8 to indicate that no ASET records will be created. The current SEP2X rule for user set specifications is to copy the supplied record from the main GEOM4 to the residual's GEOM4S.

VDA Partitioning vector--d-set size--with 1.0's at extra point degrees-of-freedom. May be purged if no extra points are specified.

SEP1X SELIST,GEOM1*,GEOM2*,GEOM4*,SETREE,SGPDTS*,BNDFIL/SEMAP,SGPDT,SCSTM/S,N,NOSE/CONFAC/QUALNAM/QUALVAL/S,N,RSFLAG/NQSET/EXTNAME/S,N,SEP1XOVR/NQMAX/SEBULK/TOLRSC/S,N,SWCHECK/ATQSET $

Bit Value Description

9 256 CHKRUN flag for spot welds

10 512 CHKRUN=2 flag for spot welds


SEP2X

Format:

Parameter:

SSG1

Format:

Input Data Blocks:

VIEWP

The format has not changed but the default for VUGJUMP was changed from 1000 to 100.

SEP2X GEOM1,GEOM2,GEOM3,GEOM4,EPT,MPT,SLIST,SEMAP,CASES,DYNAMIC,UNUSED11,SGPDT,SCSTM,MATPOOL/GEOM1S,GEOM2S,GEOM3S,GEOM4S,EPTS,MPTS,MAPS,SGPDTS,UNUSED9,DYNAMICS,MATPOOLS,UNUSED12/SEID/METHCMRS/SEP1XOVR $

SEP1XOVR Input-integer-default=0. Over-ride bits for module processing and computed in SEP1X. Checks bit 8 to determine upstream q-set processing in the residual. See Remark 3 under the SEP1X module description.

SSG1 SLT,BGPDT,CSTM,MEDGE,EST,MPT,ETT,EDT,MGG,CASECC,DIT,UG,DEQATN,DEQIND,GPSNT,CSTM0,SCSTM,GEOM4,ESTL,SLTNL0,KGG,USET/

, PTELEM,SLTH,SLTNL,PGRV/

USET/NSKIP/DSENS/APP/ALTSHAPE/TABS/SEID/COMBMETH/LGDISP/NONLNR/OGRAV $

KGG Stiffness matrix in g-set.

USET Degree-of-freedom set membership table for g-set.

PG

AG

152

I N D E XMSC.Nastran Release Guide

I N D E XMSC.Nastran Release Guide

Aadjoint loads, 9arbitrary beam cross section, 9, 96

Bbar/beam offsets, 19BIGDOT optimizer, 102, 114brake squeal, 23Bulk Data Entries

BCONTACT, 21CBUSH, 23CFAST, 56DOPTPRM, 105DRESP1, 104MDMIOUT, 16, 17MESUPER, 16NSMADD, 73NSM-type, 70PBMSECT, 96PBRSECT, 96PCONV, 75PFAST, 60TABDMP1, 126TABLEH1, 83, 84TABLEHT, 83TICD, 30TOPVAR, 103WALL, 30

CCase Control Commands

BCONTACT, 37ELSUM, 70EXTSEOUT, 16HTFLOW, 89NSM, 70SDAMPING, 126

Cauchy Stress, 18CBUSH element, 56CFAST, 57CHBDYi surface element, 75checkerboard effect, 110compliance, 104convection heat transfer coefficients, 89crash simulation, 37

Ddefault path, 17distributed memory parallel (DMP), 40, 52DMAP Modules

MATMOD, 127MPYAD, 52PNCHGRP, 44, 48PNMKGRP, 44, 46

DMP, 40dmp keyword, 42dmparallel, 42

DOT, 102

Eeigenvector sensitvity

High’s method, 117

INDEX156

element summary printout, 70enforced motion, 9error list, 10Executive Control Statements

DOMAINSOLVER, 42SOL 600, 17SOL 700, 30

external superelements, 16

FFastener Element, 56Flux Output, 89fractional mass, 104free convection heat transfer, 83

GGeometric Domain ACMS, 49

Hheat flow output, 89heat transfer coefficient, 75, 83High’s method, 117

IIFP (Input File Processing) Checking, 17

LLanczos MAXSET, 49large mass method, 49large XDB, 120load balancing, 40

Mmassless mechanisms, 49Matrix Domain ACMS, 49MDACMS, 49modal damping, 126

modal damping processing, 126modal neutral files (MNF), 17MSC.ACCESS

DBFLOC, 121OPENC, 122OPENR, 123OPENSQ, 124

MSC.Adams, 17modal neutral files, 17

Multilevel Distributed Memory Parallel (MLDMP), 40

NNASTRAN system cell

DBCFACT, 120nodal convection coefficients, 79non-uniform free convection heat transfer,

75

PParameters

AUTOQSET, 9BAILOUT, 109CFDIAG, 65CFDIAGP, 65CFRANDEL, 65DESPCH, 107MARCBUSH, 23MAROFSET, 19MSPEEDP4, 24MSPEEDSE, 24PCONV, 75, 85

pin flags, 19

Rresidual vectors, 9

Sshell offsets, 19SOL 200, 114

157INDEX

SOL 600executive control statement, 17external superelements, 16nonsupported entries, 26PATH keyword, 17thermal contact, 20

SOL 700executive control statement, 30explicit nonlinear, 28nonsupported entries, 31

spatial dependent heat transfer coefficient, 75

superelements, 16

Ttemperature-dependent stress-strain curves,

24thermal contact, 20thermal expansion

solid elements, 137topology optimization, 102

BIGDOT, 114

XXDB file, 120

Zzero density material, 116

Documents

MSC.Nastran 2005 r2 Release Guide