Introduction to FEA with MSC Apex · Refer to Section 4.3 - Tutorial Overview for video tutorials •Build FEA Model 1. Import Geometry (4.0_Stiffened_Plate.x_t) • Hide solids from

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Introduction to FEA with MSC ApexSteff Evans

Copyright© 2019 Evotech CAE Ltd

Worked Tutorials

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1.4 Worked Tutorial

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1.4 Key Steps

Refer to Section 1.3 - Tutorial Overview for video tutorials

• Build FEA Model1. Import Geometry (1.0_Prop_Blade.x_t)

2. Explore Display Controls

3. Measure Model Dimensions • help guide mesh size

4. Solid Mesh • Quadratic Element, 1.5mm mesh size

5. Show Element Quality

6. Create/Assign Material • Alu_7075, Elastic Modulus 70GPa, Poisson's Ratio 0.30, Density 2.70g/cm3

• Apply Loads and Boundary Conditions1. Create Displacement Constraints

• Clamped Constraint, Faces Pick Filter, Explore Auto/Manual Tool Execution

2. Create Force/Moment • Right and Left Force, Fz=20N, Vertices Pick Filter

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1.4 Key Steps (Continued)

• Run Simulation1. Place in Analysis Scene

• Right-Click’ Part to access

2. Review ‘Analysis Readiness’• Highlights pre-analysis errors or omissions

3. Specify ‘Static’ Analysis

4. Run the Analysis• Solver Status shown in bottom left corner

5. Post-Process

• Explore Results1. Show Fringe, Set ‘Quantity’ to Displacements

2. Show Hot Spot Display

3. Play Animation

• Further Study• Extract peak displacement to understand blade stiffness

• Explore element choice by switching to ‘linear’ element

• How does this change stiffness?

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2.4 Worked Tutorial

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2.4 Key Steps


• Create Geometry1. Import Geometry ‘2.0_Stiffened_Plate.x_t‘

2. Extract Mid-surfaces,‘Auto-Offset Selected Faces‘• pick bottom face and four stiffeners (consider auto/manual tool execution mode)

3. Split Surfaces, ‘Split surface using curve’• create edges for 1D mesh

• delete temporary stiffener surfaces

4. Vertex/Edge Drag• Drag vertices to connect split edges

• Create 1D/2D Mesh1. Surface Mesh

• 2mm Mesh Size

2. Defeature Geometry, ‘By Identified Feature’, • remove all holes, all chamfers and fillets < 10.5mm

3. Element Quality Check

4. Curve Mesh Stiffener Edges• Mesh size is determined by connected 2D mesh

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• Assign 2D Properties 1. Measure Solid to calculate plate thickness/stiffener height

2. Auto-Thickness to generate section properties

3. Show Thickness, 3D thickness and offset

• Assign 1D Properties1. Check Shell Normal

2. Element Orientation, ‘Reverse Element Orientations‘• ensure normals point in ‘-Z‘

3. Create Beam Shape• solid rectangle, width 2mm, height 9mm

4. Create Beam Span• ‘Stiffener‘, ‘Constant Section‘ Y(-), Top‘

5. Create/Assign Material• Alu_7075, Elastic Modulus 70GPa, Poisson's Ratio 0.30, Density 2.70g/cm3

• Further Study• Investigate further 2D model build through;

• Import ‘2.0_Leg_Lower.x_t’ and 2D Mesh (1.5mm mesh size)

• Defeature holes/fillets to improve mesh quality

• Use ‘Auto-Thickness’ to generate section properties

• Use ‘Section View’ to finalise section Properties

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3.4 Worked Tutorial

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3.4 Key Steps


• Solid Meshing1. Import Geometry ‘3.0_Rotor_Hub.x_t‘

• view model in transparent mode to understand structure

2. Measure Distance• typical wall thickness used to define mesh size

3. Solid Mesh• quadratic elements, 1mm mesh size, default controls

4. Element Quality Check• dominated by good elements, small percentage poor, no invalid

• Solid Mesh Controls1. Import Geometry ‘3.0_Rotor_Hub.x_t‘ (using same geometry as previous example)

2. Split Geometry• ‘split using plane’ and ‘split using surface’ to ‘partition’ model into cells for transition meshing

3. Solid Mesh Discrete Cells• set pick filter to ‘cells’, mesh inner cell at 0.50mm and two outer regions at 1.25mm


5. Mesh Topology Check• only ‘feature edges’ (green) shown, highlighting mesh connectivity between cells

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• 2.5D Meshing1. Import Geometry ‘3.0_Rotor_Hub_Hex.x_t‘

• hide surfaces (they‘ll be used for splittting cells later)

2. Defeature Geometry• ‘by identified feature‘ to find and delete 3D fillets

3. Display 2.5D Colour

4. Split Geometry• ‘split using plane’ and ‘split using surface’ to ‘partition’ model into cells for transition meshing

• mappable cells will turn green after splitting

• repeat until complete solid is mappable

5. 2.5D Meshing• 1.0mm mesh size, default controls


• Further Study• Import Geometry ‘3.0_Rotor_Hub_Hex.x_t‘

• split into a single mappable solid (leave 3D fillets in original definition)

• 0.75mm mesh size

• define axial loading scenario

• compare solve time and response against Tet10 mesh representation

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4.4 Worked Tutorial

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4.4 Key Steps


• Build FEA Model1. Import Geometry (4.0_Stiffened_Plate.x_t)

• Hide solids from view (either display controls or model browser)

2. Create Seed Points• Force mesh to respect underlying fastener (and boundary condition) locations

3. Create Surface Mesh• 3mm mesh size

4. Check Shell Normals/Free Edges

5. Create Materials via Macro (Evotech_Material_Database_20190227.py)

6. Assign Materials• Aluminium for main part, titanium for stiffeners (use ‘face’ picking filter)

• Set Up and Analyse FEA Model1. Create Spherical Boundary Condition

• Hide surfaces from view (either display controls or model browser)

2. Create Pressure Load• Test ‘psi’ to ‘MPa’ unit conversion

3. Place in Analysis Scene• Correct any ‘Analysis Readiness’ failures

4. Run Analysis

5. Post-Process

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• Build Composite FEA Model1. Import Geometry (4.0_Composite_Plate.x_t)

2. Create Seed Points

3. Create Surface Mesh• 3mm mesh size

4. Check Shell Normals

5. Create Materials via Macro (Evotech_Material_Database_20190227.py)

• Build Composite Lay-Up1. Create Panel and Plies

• Specify Build Direction and Material Orientation

• Add plies by specifying Material, Thickness, Angle and region to build lay-up. Change ply colors to aid visualisation, if desired

2. Core Sample• Display resultant lay-up with 3D Thickness and Core Sample tools

• Use ‘2D elements’ pick filter for discrete regions

• Further Study• Modify mesh to allow ‘patch’ ply definition

• Split surface into smaller regions (mesh and composite properties will update automatically)

• Add new ‘patch’ plies to current lay-up

• Core Sample to check ply distribution and thickness

• Run analysis and post-process Composite Failure data

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5.4 Worked Tutorial

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5.4 Key Steps


• Model Build1. Import Geometry (5.0_Model_Connections.x_t)

2. Create Materials via Macro/Assign Materials (Evotech_Material_Database_20190227.py)• Assign ‘Iso:Aluminum 7075 T6’ to all entities (global sweep of model)

3. Create Surface/Solid/2D Mesh• Surface mesh size 3mm, all surfaces (default mesh parameters)

• 2.5D mesh size 1mm, mappable solids, use linear element (Hex8)

• Solid mesh size 1mm, remaining solid, use linear element (Tet4)

• Use surface/solid pick filters where necessary

4. Assign Shell Section• Create Section, ‘2mm_shell’, thickness = 2mm, offset = 0mm

• Assign to all surfaces, use surface/solid pick filters where necessary

• Glue and Connectors1. Show Only Pairs ‘1.0’ and ‘5.0’ (for glue connection)

• ‘Right-Click’ Model Browser entities, ‘Show Only’

2. Create Glue Pairs (between disconnected mesh entities)• Select all entities, default glue parameters

• Glue can be viewed under each part in Model Browser

3. Show Only Pairs ‘2.0’ and ‘4.0’ (for connector definition)

4. Measure Fastener Diameter (for connector properties)• Select fastener hole to give diameter

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• Glue and Connectors (continued)5. Create Connectors

• Create connector, ‘Flexible Link’ ,

• Name ‘2.0/4.0’, Diameter 3.0mm, Material Iso:Titanium 6Al 4V

• ‘Auto Locate Method…’/Compliant end types

• Select discrete edge of holes to build connectors (4 in total)

• Switching between ‘Auto/Manual’ Execution Mode and using ‘Edges’ pick filter may help selection

• ‘Connectors’ can be viewed in Model Browser

6. Repeat Show/Create Connectors for Pairs ‘4.0/5.0’ & ‘3.0/5.0’ • Repeat for each pair of fastened parts, use same diameter/material

• Name each fastener type accordingly, e.g. Name ‘4.0/5.0’

• Resultant fastener count; ‘4.0/5.0’, 2 connectors & ‘3.0/5.0’, 4 connectors

• Further Study• Create Revolute Joint between ‘1.0_Propeller’ and ‘5.0_Leg_Upper’

• Use Manual Execution Mode to allow selection of lower leg fastener faces and propeller bore

• Turn off ‘Auto defined joint axis location’ and specify ‘-159.10, -159.10, 71.75 mm’ as joint location

• ‘Joints’ can be viewed in Model Browser

• Run Unconstrained Normal Modes analysis to visualise propeller rotation • There should be 6 ‘standard’ rigid body modes, with an additional mode representing the propeller rotational

freedom at the joint.

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6.4 Worked Tutorial

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6.4 Key Steps


• Assembly Build1. Import Geometry (6.0_Assembly_Modeling.x_t)

• Hide upper/lower plates

2. Transform Parts• Translate/Copy all remaining bodies

• ‘Unlock the Manipulator’, re-centre at ‘0,0,0’, then re-lock, (tap ‘R’ to switch to Rotate mode)

• Copy entities three times, 90/180/270°

3. Add New Parts• Add five new parts, and rename; 1.0_Prop_Blade,2.0_Rotor_Hub, 3.0_Leg_Upper, 4.0_Plates, 5.0_Leg_Lower

4. Populate New Parts• Cut/paste bodies into respective new parts (show/hide parts will aid selection)

• Cut/paste new parts under ‘6.0_Assembly_Modeling’ master assembly

• Model Build1. Mesh Parts

• Mesh size; Surface Mesh 2.5mm, 2.5D Mesh 2.0mm, Solid Mesh 2.0mm (Linear, Tet4 for solver brevity)

• Use surface/solid picking filters to aid selection

2. Create Materials/Sections • Run material macro (Evotech_Material_Database_20190227.py), assign ‘Iso:Aluminum 7075 T6’ to all entities

• Assign 2mm section to all surface entities

3. Create Glue Contact• Create Glue contact to full assembly, Glue Pair Tolerance, 1mm

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• Part and Assembly Verification1. Post Part to be Verified

• Post ‘3.0_Leg_Upper’

2. Create Boundary Conditions• Fixed region for each leg

• Required as there are more than one bodies in the Part (i.e. without boundary conditions there would be 24 Rigid Body Modes)

3. Place in Analysis Scene and Solve• Normal Modes analysis to assess mode shapes

• Verified model will show modes 1+ as Elastic (i.e. no Rigid Body Modes present)

4. Repeat for Full Assembly• Repeat at Part and/or full Assembly level to verify full structure

• Model can now be used for down-stream analysis with confidence

• Further Study - Model Representation• Create a Model Representation for the full Assembly

• Create a second Model Representation for the full Assembly with the Upper Plate removed• Create a new Part, ‘4.1_Plate_Upper’

• Cut/Paste Upper Plate body into the new Part

• Move new Part into full Assembly

• Highlight and rename Glue Pairs to allow easy selection during Model Representation selection

• Create Model Representation with ‘4.1_Plate_Upper’ and key Glue Pairs deselected

• Compare Normal Mode response between Model Representations

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7.4 Worked Tutorial

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7.4 Key Steps


• Analysis Set-Up1. Create and Save New Model as ‘7.0_Analysis_Model’

2. Import Geometry, ‘7.0_Analysis_Model.x_t’

3. Run Macro, ‘7.0_Analysis_Model_Build.py’• Generates full assembly model, including Glue Contact, Materials and Sections

4. Place in Analysis Scene• ‘Right-Click’ on ‘7.0_Analysis_Model’ assembly in Model Browser

5. Switch ‘Environment Type’ to Normal Modes

6. Analysis Readiness Check/Update• Add Density (2.81g/cm3) to Al_7075 via ‘Missing Material Properties’

• Run the Analysis1. Generate a Simulation Scenario

2. Specify Output Requests• Untick ‘Constraint Reaction Forces’

3. Run the Analysis• Solution will take less than one minute

4. Post-Process• Enter the post-processing environment for result exploration

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• Post-Process1. Visualise Deformed Shape and Fringe

• Look at Deformed Shape and Fringe Options

2. Post Data Grid/View Modes• Selecting Mode from Data Table will update model visualisation

• Note – 6 ‘rigid body’, 7+ ‘elastic’ modes. Minimise Model Browser to simplify view

3. Export Data• Export Modes Table to external *.csv file

• Further Study – Static Analysis with Multiple Events• Create Gravity Loads for ‘Flight’ and ‘Crash’ events

• ‘Flight_Vertical_-Z_1g’, magnitude ‘1.0 g’ acting in ‘Global –Z’ direction

• ‘Crash_Vertical_-Z_5g’, magnitude ‘5.0 g’ acting in ‘Global –Z’ direction

• Create ‘General’ Displacement Constraints for ‘Flight’ and ‘Crash’ events• ‘Flight_DOF-Z’, constrained only in ‘Translation Z’ at hub axle centre vertices (this allows model to ‘hang’ from propellers during

flight), use ‘Vertices’ selection filters to aid picking

• Crash_DOF-Z’, constrained only in ‘Translation Z’ at lower leg bottom faces (this allows model to ‘impact’ the ground during crash), use ‘Faces’ selection filters to aid picking

• Create ‘General’ Displacement Constraints to avoid Rigid Body motion• ‘Rigid_Body_DOF-XY’, constrained in ‘Translation X&Y’ at upper plate centre vertex (this constrains motion in the X and Y

directions)

• ‘Rigid_Body_DOF-X’, constrained in ‘Translation X’ at upper plate edge (any single edge vertex or node – this constrains rotation about the Z axis)

• Generate Simulation Scenario (with two events), Run Analysis and Post-Process

Event 1 (Flight) Loads Constraints Event 2 (Crash) Loads ConstraintsFlight_Vertical_-Z_1g Flight_DOF-Z Crash_Vertical_-Z_5g Crash_DOF-Z

Rigid_Body_DOF-XY Rigid_Body_DOF-XYRigid_Body_DOF-X Rigid_Body_DOF-X

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8.4 Worked Tutorial

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8.4 Key Steps


• External FEA Data Import1. Create and Save New Model, ‘8.0_InterOp_Model’

2. Import FEM (External FEA Data), ‘8.0_InterOp_Model.bdf’• ‘mm-t-s-N’ Unit System and ‘Organise by contiguous mesh regions’

3. Review Imported Data• Unsupported Keywords written directly to ‘Direct Text Input’

4. Run Macro, ‘8.0_InterOp_Model_Build.py’• Generate Assembly Model Architecture with Glue Contact

• Verify External FEA Data1. Apply Pressure Load

• 0.1 MPa applied to upper plate ‘4.0_Plates/…Mesh_13…’

2. Place in Analysis Scene• ‘Right Click’ on ‘8.0_InterOp_Model.1’

3. Run the Analysis• Solution will take less than one minute

4. Post-Process• Explore Deformed Shape to show verified model and boundary condition response

• Exit Post-Processing once complete

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• External MSC Nastran Analysis1. Place in Analysis Scene

• Select ‘Buckling’ Environment Type

2. Generate a Simulation Scenario

3. Review Bucking Events• ‘Gravity –Z 5g’ acting as Pre-Load, held as pressure load applied for Buckling Analysis

4. Export FEA Data• ‘Right Click’ on ‘Buckling Scenario…’ to export BDF data to desired file location, ‘mm-t-s-N’ Unit System

5. Run External MSC Nastran FEA

6. Import MSC Nastran Results• Right Click’ on ‘Buckling Scenario…’ to import H5 result data to desired file location

7. Post-Process

• Further Study - Orphan Mesh Workflow (from previous)• ‘Create Faceted Surfaces’ for Shell Meshes contained within Part ‘3.0_Leg_Upper’

• Once surfaces are created, underlying shell meshes can be deleted, shell property links will be maintained

• Import Geometry, ‘8.0_InterOp_Model_Geometry_Update.x_t’• Boolean Subtraction to remove lightening holes from faceted surfaces

• Re-mesh Faceted Surfaces (1mm mesh size) to reflect new geometry

• Delete and regenerate broken glue contacts within part

• Normal Modes Verification for full assembly

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Introduction to FEA with MSC ApexSteff Evans


Appendix

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Appendix- Apex Introduction Card

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Appendix – Mouse Shortcuts

Functionality Mouse Shortcut

• Rotate - Drag MMB

• Pan - Drag RMB

• Zoom - Drag (MMB +LMB together) or Drag (MMB + RMB together) or Scroll Wheel

• Fit view - Click (LMB + RMB together)

• Fit isometric view - Hold down on (LMB + RMB together) for longer than 0.4 seconds

• Window zoom - Drag (LMB + RMB together)

• Toggle pan/rotate - While dragging MMB if you click LMB or RMB

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Documents

Introduction to FEA with MSC Apex · Refer to Section 4.3 - Tutorial Overview for video tutorials •Build FEA Model 1. Import Geometry (4.0_Stiffened_Plate.x_t) • Hide solids from