View
1.382
Download
3
Embed Size (px)
DESCRIPTION
Citation preview
Innovation Intelligence®
Application of OptiStruct to Solution
of Powertrain Problems
Woytek Tworzydlo
AETC - April 24, 2013
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Altair OptiStruct
• A comprehensive high-performance FE-solver and optimizer
• Solution sequences:
• Statics (small deformations)
• Non-linear contact
• Non-linear materials
• Heat Transfer
• Comprehensive NVH Solution
• Normal modes
• Frequency response
• Transient Analysis
• Acoustic Analysis
• Easy to use
• robust element formulations
• thorough model check, informative messages
• Seamlessly integrated with optimization
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
OptiStruct for Powertrain Applications
New advanced analysis and optimization capabilities have been added in
version 12.0 addressing specific needs of Powertrain modeling:
Gaskets
Fine details
Contact
Large models
Heat transfer
Vibrations
Second order
elements
Global - local
Bolt
tensioning
Moving parts
Thermal loads
Nonlinear
Pre-tensioning
Gaskets
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Powertrain Modeling Requirements
Contact • Hertz contact conditions with friction
• Contact friendly 2nd order solid & 3D gasket elements
• Thermal contact – conductivity ƒ(gap, pressure)
• Coupled thermal and static analysis
3-dof Gaskets • Nonlinear behavior in thickness direction
• Optional 3D stiffness
• Pressure, Leakage status
Pretensioned bolts (1D & 3D)
Non-linear materials w/ plasticity • Isotropic, kinematic and mixed hardening
• Metals, gray cast iron
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
OptiStruct 12.0 – Pretensioned Bolts
• Pretensioning of bolted assemblies
• “Cut and Load” approach
• 1D bolts
• Surface cut on a 3D bold model
• Logical and general flow
• pretension Force
• pretension Adjustment
• arbitrary combinations and sequencing
• Available for use with
• Static analysis (linear and nonlinear)
• Preloaded normal modes
• Preloaded frequency response
• Optimization…
Surface
Pretension and Ignition
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
OptiStruct 12.0 – Gasket Elements
• Single material to model behavior
of complex gasket profiles
• FE Modeling
• Unique behavior in normal direction
• Highly nonlinear
• Large “strain” (closure)
• Based on experimental curves
• First and second-order elements
• CGASK6, … 8, 12, 16
• Contact-friendly version available
Complex structure
in real life
One ‘material’
in FE world
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Gasket Elements – cont’d
• Result types
• closure, stress, pressure, sealing status
• Robust behavior
• normal compression only, or full 3D stiffness
• works over cutouts, etc.
Displacements (to scale) Gasket pressure
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
OptiStruct 12.0 Plasticity Enhancements
• Von Mises plasticity. Isotropic, kinematic and mixed hardening.
• solids and shells
• good nonlinear convergence
• easy to use – automatically switch the element formulation for elasto-plastic
regions
Plastic
Strain
Residual Stress after unloading
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
OptiStruct 12.0 CONTACT/Friction Improvements
• Improved convergence with Friction
• nonsymmetric solver
• new friction model
• stabilized Expert System – prevents
fly-away of disconnected parts
• Improved contact on imperfect meshes
• CLEARANCE
• ADJUST – (12.220)
• smoother solution
P
F
CLEARANCE
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
STANDARD IMPROVED
OptiStruct 12.0 – Contact-Friendly Elements
• Contact-friendly second-order elements (solids, gaskets – all types)
• more realistic contact forces
• elasticity and elasto-plasticity
• Benefits
• better nonlinear convergence
• improved CONTACT pressure
• improved open/closed status
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Thermal (Heat Transfer) in OptiStruct 12.0
• Available thermal solutions (12.0 - linear)
• Conduction, surface convection & heat
generation
• Coupled thermal / structural analysis
• Transient thermal, coupled transient thermal /
structural
• Surface heating from fluid - Acusolve
• Heat transfer across CONTACTs
• gap-dependent conductivity
• pressure-dependent (in 12.210)
• Optimization for coupled thermal /
structural problems pressure gap
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Powerful NVH Capabilities
• Core NVH Solutions
• Normal modes
• Frequency response
• Random Response
• Transient Analysis
• Acoustic Analysis
• AMSES fast eigenvalue solver
• Advanced Post-Processing
• TPA (Transfer Path Analysis)
• Modal Participation
• DSA (Design Sensitivity Analysis)
• Automatic filtering – PEAKOUT
F
r Ff
F
r F
f
F
t F
e
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Setup in Hypermesh and SimLab - Pretension
• Hypermesh
• 12.0 - use Loads panel
• Pretension Manager (in 12.0.110)
• Simlab
• specialized pretension setup
page and tools
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Contact Definition Tools
• HyperMesh
• Auto-Contact manager -
(in 12.110)
• SimLab
• Automated Contact manager
Copyright © 2013 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Example: Engine Assembly System Model
Subcase 1:
• Bolt Pretension in Head Bolts
Subcase 2:
• Lock Pre-tension Displacements
• Apply Temperature Loading
Subcase 3:
• Lock Pre-tension Displacements
• Continue Temperature Loading
• Apply Combustion Pressure Loading
Thermo-structural Model
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Gasket loading curve
Gasket un-loading curve
Model Features
• 3D pretension bolts
• Gasket material
• 2nd order modified
tetrahedral elements
• Contact with friction (0.1)
• Tied contacts
(total = 130)
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
• Apply Pre-tension Loading (41.25 KN) in Head Bolts
Subcase 1
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 1: Stresses in Bolts
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 1: Gasket Pressure and Sealing Status
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
• Lock Pre-tension Displacements
• Apply Temperature Loading
Subcase 2
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Cylinder Head
Subcase 2: Temperature Distribution Load Applied
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 2: Stress Contour
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 2: Contact Pressure Distribution
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
• Lock Pre-tension Displacements
• Continue Temperature Loading
• Apply Combustion Pressure Loading
Subcase 3
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 3: Combustion Pressure Load Application
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 3: Stress Contour
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
The top and bottom edge
deformation of the bores are
shown in next slide
Top edge
Bottom edge
Subcase 3: Bore Deformations
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Subcase 2
Scaled 300x
Subcase 1
Scaled 3000x
Subcase 3
Scaled 300x
Bore Deformations
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Example – Connecting Rod Optimization
• Analysis setup
• interference fit
• bolt pretension
• contact with friction
• bearing pressure load
• Free shape optimization setup
• Design Constraints: Stresses
• Objective: Minimize Volume
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Results of Free Shape Optimization
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Results of Free Shape Optimization
• Weight – unchanged
• Stress constraint violation (by 50%) eliminated
Shape Change
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
OptiStruct for Powertrain - Summary
Courtesy PSA Peugeot Citroën
• Software of choice for Powertrain modeling
• sealing pressure with bolt pretension
• nonlinear structural analysis
• thermal solution (heat transfer)
• NVH
• Highly accurate
• Modeling errors detected*
• Some are fixed automatically
• Easy to use
• Best formulation picked automatically
• Integrated optimization
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Upcoming Version 12.210
• Preprocessing
• pretension manager in HyperMesh
• auto-contact in HyperMesh
• improved import/translation of other solver’s decks
• CONTACT
• ADJUST
• more results (friction, contact status, …)
• Gasket
• temperature-dependent material properties
• Thermal - Nonlinear
• temperature-dependent materials
• pressure-dependent contact
• radiation
A complete package for Powertrain Analysis and Optimization