Airbag Development Process Using

HyperWorks Automation

Nirmal Narayan

Jill Bentz

Harry Park

Terry Sella

Russ Morris

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

Objective

• Understand the airbag development process.

• Demonstrate an example of the automation using Altair TCL/TK.

Autoliv – Vision & Mission

The Worldwide leader in Automotive Safety Systems

Autoliv in Brief

Sales By Region

Autoliv Products

Having an Impact

- US Highway Fatality Rate Drops to 62 Year Low

- For 2011, the highway fatality rate was 32,300 people.

PAB Development Process

Step 1: Start with vehicle data

Centerline cross-section Occupant size and positions Pulse information

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

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?

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

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

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

Typical Airbag CAE Analysis

• Airbag Volume Analysis

• Coverage Study

• Stress Analysis

• Linear Impactor

• Sled Systems Simulation

• Full Vehicle Crash Analysis

CO

MP

LE

XIT

Y

3D to 2D Simulation Based Method

3D to 2D SIMULATION

CAD DATA GENERATION

Volume Analysis using Simulation Methods

3D CAD

DATA

GENERATE

MESH FEA SOLVER VOLUME

2D CAD

DATA

GENERATE

MESH FEA SOLVER VOLUME

AIRBAG

STITCHING

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

Automation Demo

Volume Analysis Report

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.

CATIA CAD SELECT

MATERIAL CREATE

MESH APPLY

PRESSURE

SUBMIT TO

SOLVER GENERATE

REPORT

STAND ALONE APPLICATION

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.