Design and development of airbags involves initial designing, optimizing, prototyping and testing. This process could be time consuming and costly since multiple iterations are performed before a final design is achieved. CAE tools can effectively be used in the airbag development process to reduce the design cycle time and to reduce development costs. Furthermore, in a CAE driven development process, higher productivity gains could be achieved by automating the routine CAE processes. In this presentation, some of the efficiency gains achieved on the airbag design process by using Altair HyperWorks Automation are presented.

1. Airbag Development Process Using
HyperWorks Automation
Nirmal Narayan
Jill Bentz
Harry Park
Terry Sella
Russ Morris

2. Agenda
• About Autoliv
• Airbag Development Process
• Typical Airbag CAE Analysis
• Simulation Based Volume Analysis
• Demo- Automation of Volume Analysis using TCL/TK
• Future steps and Summary
• Q&A

3. Objective
• Understand the airbag development process.
• Demonstrate an example of the automation using Altair TCL/TK.

5. Autoliv – Vision & Mission
The Worldwide leader in Automotive Safety Systems

6. Autoliv in Brief
Sales By Region

7. Autoliv Products

8. Having an Impact
- US Highway Fatality Rate Drops to 62 Year Low
- For 2011, the highway fatality rate was 32,300 people.

10. PAB Development Process
Step 1: Start with vehicle data
 Centerline cross-section
 Occupant size and positions
 Pulse information

11. PAB Development Process
Step 2: System or application engineer defines cushion profile or
profiles:
 Incorporate best practices for different crash scenarios
 Select main panel shape or define 3D shape
Try 1 Try 2

12. PAB Development Process
Step 3: CAE analyst creates a cushion model
 Volume calculation at 1 psi. for inflator sizing
 Static deployment in environment for deployed shape
Volume @ 1psi. Static deployment
Satisfied with cushion volume and shape?

13. PAB Development Process
Step 4: Run system model with new PAB designs
 Belted AF05 (new NCAP), Unbelted AM50
 Tune vent sizes, tether length, inflator output, adaptive
vent, belt load
Satisfied with cushion performance?
“No” → redesign
“Yes” → now we need cushions for testing

14. PAB Development Process
Step 5: Kick off drawing to build prototype cushions
 Once we have a good candidate design …
 CAE analyst “unwraps” 3D model to 2D flat panels
 Geometry based (mathematical scripts)
 Simulation based
 2D line data becomes basis for cushion assembly drawing
3D model 2D flat pattern

15. PAB Development Process
Step 6: Prototype cushions
 Prototype cushions for integrity testing
 Fold and tether confirmation
 If QA okay, then proceed with on to OOP or sled testing

17. Typical Airbag CAE Analysis
• Airbag Volume Analysis
• Coverage Study
COMPLEXITY
• Stress Analysis
• Linear Impactor
• Sled Systems Simulation
• Full Vehicle Crash Analysis

19. 3D to 2D Simulation Based Method
3D to 2D
SIMULATION
CAD DATA
GENERATION

21. Volume Analysis using Simulation Methods
3D CAD GENERATE FEA SOLVER VOLUME
DATA MESH
2D CAD GENERATE AIRBAG
FEA SOLVER VOLUME
DATA MESH STITCHING

23. Case Study: Automation of Airbag Stitching
• Performing volume analysis using 2D panels, involves stitching of
panels together to create 3D enclosed volume.
• Automation achieved by Altair TCL/TK scripts.
• Manual stitching takes hours and is a tiresome process.
• With automation the stitching could be done in minutes.
TCL/TK
SCRIPTS

24. Automation Demo

25. Volume Analysis Report

27. Future Steps
• Identity routine simple CAE analysis which can be easily automated.
• Develop a one click application to get the highest productivity
• For example, the volume analysis is performed routinely and sometimes can be
time consuming.
• Develop a stand-alone application which reads CAD data and can create the
volume report.
• Make the application simple enough, so that any non CAE persons in the
organization can use it.
CREATE SELECT APPLY
CATIA CAD
MESH MATERIAL PRESSURE
GENERATE SUBMIT TO
REPORT SOLVER
STAND ALONE APPLICATION

28. Summary
• Airbag development is a multi step iterative process.
• CAE is extensively used in the airbag development in each of the steps.
• Automation can be used to effectively reduce the development time and
increase productivity.