KIRCHHOFF GRUPPE

Using Strain Hardening for Advanced Structural Analysis Quality of Vehicle Components

Author: Jasmin Brühmann

Kirchhoff Automotive Deutschland GmbH, Attendorn, Germany

(+49-2722-696-0)

KIRCHHOFF GRUPPE

2 [09.11.2011 /Bruehmann]

Agenda

• Introduction

• Problem Defintion

• Analysis/Discussions

Accuracy of HyperForm OneStep

Effects of Strain Hardening

• Conclusions

KIRCHHOFF GRUPPE

Introduction

• Lightweight for crash-relevant parts with new high-strength steels

high levels of strain hardening

lower thickness but same strength

3 [09.11.2011 /Bruehmann]

VW Polo V

Reference: Simulation des Versagens von pressgehärteten Bauteilen aus 22MnB5 + AS80 , Kirchhoff Autmotive GmbH, 2010

KIRCHHOFF GRUPPE

Problem Definition- Forming Simulation

4 [09.11.2011 /Bruehmann]

„Inverse one-step method“

quick and easy but less accurate

needs material and geometry data

HyperForm

OneStep

HyperForm

Radioss Incremental

„Incremental“

more time for model setup

also needs data about tool and process

KIRCHHOFF GRUPPE

Problem Definition- Mapping Results

5 [09.11.2011 /Bruehmann]

HyperMesh HyperCrash

Structural

model

Results forming

simulation

KIRCHHOFF GRUPPE

Analysis Accuracy of HyperForm OneStep (B-Pillar)

• Average deviation of thickness (in comparison to formed part):

Used Software: 0,10 mm (+)

HyperForm Radioss Incremental: 0,10 mm (+/-)

HyperForm OneStep: 0,15 mm (+/-)

• different proportions (force level in structural analysis):

increasing force level caused by plastic strain

decreasing force level caused by thickness reduction

• but finally nearly same results of structural analysis

6 [09.11.2011 /Bruehmann]

KIRCHHOFF GRUPPE

Analysis Accuracy of HyperForm OneStep (sub-shell of side member)

7 [09.11.2011 /Bruehmann]

Used Software

KIRCHHOFF GRUPPE

Analysis- Effects of strain-hardening on structural behaviour under loading - B-Pillar HCT580X

8 [09.11.2011 /Bruehmann]

Used Software

KIRCHHOFF GRUPPE

Analysis - Effects of strain-hardening on structural behaviour under loading – Side member LH800

9 [09.11.2011 /Bruehmann]

KIRCHHOFF GRUPPE

Analysis - Effects of strain-hardening on structural behaviour under loading – Crash-Box HC300LA / HC380LA

10 [09.11.2011 /Bruehmann]

Used Software

KIRCHHOFF GRUPPE

Conclusions

• Improvement of results depends on part geometry

• Accuracy differences between HyperForm OneStep and Used Incremental Software

x 1/100mm – differences of thickness calculated in forming simulation

a few percent of forcelevel in structure simulation

HyperForm OneStep is suitable for prediction of strain hardening

useful early in the product developement cycle

• Results of HyperForm Radioss Incremental are of equivalent quality

• Results Mapping will be easier

Results Initializer in HyperWorks 11.0

11 [09.11.2011 /Bruehmann]

KIRCHHOFF GRUPPE

Thank you for your attention!

12 [09.11.2011 /Bruehmann]