Tutorial 2 :Create an LS-DYNA input deck for a simple inflatable airbag

Transcription

1 Tutorial 2 :Create an LS-DYNA input deck for a simple inflatable airbag Case description: Airbag: shell elements, fabric material Constraints: none Files required: curves.k Step 1: Create a circle 1. Geometry Curve Circle 2. select Parameters 3. enter Origin Point (0,0,0) 4. enter Radius: click Apply 6. enter Radius: click Apply

2 Step 2: Mesh the circle 1. FEM Element and Mesh Blank Mesher 2. select Curve 3. pick 330mm curve from graphics window 4. click Create 5. click Accept 6. click Done Step 3: Translate and copy the mesh 1. FEM Element Tools Transform

3 2. select Translate 3. select Direction: Z 4. enter Distance: 1 5. activate Copy Elem 6. enter Part ID: 2 7. select ByPart in gen select panel 8. pick part from graphics window 9. click Tran+ 10. click Accept 11. click Done Step 4:Prepare outer edges of bag 1. FEM Model and Part Assembly and Select Part 2. select Part 3. select S1 4. click Edge render button 5. click Apply 6. click Done

4 7. FEM Element Tools Transform 8. enter Distance: deactivate Copy Elem 10. click Visible in gen select panel 11. click Tran+ 12. click Accept 13. click Done

5 14. FEM Model and Part Assembly and Select Part 15. select S2 from the list 16. click Apply 17. click Done 18. click Edge render button

6 19. FEM Element Tools Transform 20. click Visible in gen select panel 21. click Tran- 22. click Accept 23. click Done

7 24. FEM Model and Part Assembly and Select Part 25. select S1 and S2 from the list 26. click ShaEle render button

8 Step 5: Sew outer edges of bag together 1. FEM Element Tools Duplicate Nodes 2. click Show Dup Nodes 3. click Merge Dup Nodes 4. click Accept 5. activate Show Free Edges Step 6:Trim hole for inlet 1. FEM Model and Part Asembly and Select Part 2. select PartID 1 from the list 3. FEM Element Tools Part Trim 4. pick part from graphics window 5. activate Trim Tool: Curves 6. pick 30mm circle from graphics window 7. click Trim 8. click Accept 9. click Done

9 10. FEM Element Tools Transform 11. enter Distance: select ByElem in gen select panel 13. activate Prop in gen select panel 14. pick element inside 30mm circle from graphics window 15. click Tran- 16. click Accept 17. click Done

10 Step 7:Turn off geometry 1. FEM Element Tools Duplicate Nodes 2. deactivate Show Free Edges

11 3. Geometry Geometry Tools Management 4. click (un)blkall Step 8: Create cylindrical inlet 1. FEM Element and Mesh Element Generation 2. select Shell 3. select Shell By: Edge_drag 4. enter Thickness: enter Segment: 2 6. click Z 7. activate Prop in gen select panel 8. select Ang: 45.0 in gen select panel 9. pick edge of 30mm disk from graphics window

12 10. click Create 11. click Accept 12. click Done Step 9: Organize and merge elements 1. FEM Element Tools Move or Copy 2. enter PID: 1 3. click Visible in gen select panel 4. click Apply 5. click Accept 6. click Done

13 7. FEM Element Tools Duplicate Nodes 8. click Show Dup Nodes 9. click Merge Dup Nodes 10. click Accept 11. click Done

14 Step 10: delete part3 1. FEM Model and Part Keyword Manager 2. click PART 3. click Edit 4. select part3 from the pop-up window 5. click Delete 6. click Done

15 Step 11: Define section properties 1. FEM Model and Part Keyword Manager 2. select All 3. select SECTION SHELL from the list 4. click Edit 5. click NewID in the KEYWORD INPUT Form 6. enter ICOMP=1 7. enter ELFORM=5 8. enter T1= click Accept 10. click Done

16 Step 12:Define material 1. select MAT from the Keyword Manager Dialog 2. select 034-FABRIC 3. click Edit 4. click NewID in the KEYWORD INPUT Form 5. enter RO=8.7e-7 6. enter EA= enter PRBA= enter DAMP= click Accept 10. click Done Step 13:Assign section properties and material 1. FEM Model and Part Part Data 2. select Assign 3. select "S 1" and "S 2" from the list (hold down the Ctrl key while clicking) 4. click SECID in bottom panel 5. select 1 and click Done in Link SECTION Dialog 6. click MID in bottom panel 7. select 1 and click Done in Link MAT Dialog 8. click Assign Part: Apply 9. click Done

17 Step 14: Create part set & Import airbag curve 1. FEM Model and Part Create Entity 2. select *SET_PART from the list 3. select Cre 4. enter Title: bag parts 5. click Visible in gen select panel 6. click Apply 7. click Done

18 8. File Import LS-DYNA Keyword File 9. select curves.k 10. click Import Offset Step 15: Define airbag 1. FEM Model and Part Keyword Manager 2. select HYBRID from the list 3. click Edit 4. click NewID in the KEYWORD INPUT popup form 5. enter ID=1 6. enter Title: hybrid bag 7. set SIDTYP=1 8. click SID button (dot) 9. select bag parts and click Done in Link SET Dialog 10. enter ATMOST= enter ATMOSP=1.01e enter ATMOSD=1.29e enter GC=8.314

19 14. enter MW= enter INITM=1 16. enter A= enter B=C=0 18. enter FMASS= click Insert 20. click LCIDM button (dot) 21. select curve 1 in Link DEFINE Dialog 22. click Done 23. click LCIDT button (dot) 24. select curve 2 in Link DEFINE Dialog 25. click Done 26. modify MW= modify INITM= modify A= click Insert 30. click Accept 31. click Done

20 Step 16: Set termination time 1. FEM Model and Part Keyword Manager 2. select CONTROL TEMINATION from the list 3. click Edit 4. enter ENDTIM=30 in the KEYWORD INPUT popup form 5. click Accept 6. click Done

21 Step 17: Set d3plot frequency 1. select DATABASE BINARY_D3PLOT from the list 2. click Edit 3. enter DT=1 in the KEYWORD INPUT popup form 4. click Accept 5. click Done Step 18: Set ASCII time history outputs & Save the model 1. select ASCII_option from the list 2. click Edit 3. enter Default DT=0.1 in the KEYWORD INPUT popup form 4. activate GLSTAT (global statistics) 5. activate MATSUM (material energy summary)

22 6. activate ABSTAT (airbag status) 7. click Accept 8. click Done 9. File Save Keyword

23 10. click Browse and enter Filename: mybag.k 11. deselect BySubSystem 12. click Save If the preceding steps were followed correctly, your input file should look like this: mybag.k