An experimental and numerical investigation into the dynamic crash testing of vehicle bumper fabricated using friction stir welding and gas metal arc welding

Abstract

The advancement in friction stir welding (FSW) technology has provided automotive and aerospace industry with an alternative method in developing structures and assemblies. This study investigates the performance of FSW and gas metal arc welding (GMAW) on road vehicle bumpers. The method of investigation is to weld the bumper to the crash-box, and the assembly is mounted onto a moving deformable barrier before a dynamic crash test is performed. The bumper and crash-box is fabricated from AA6082-T6 and AA6063-T6 extrusions, respectively. In the first part of the study, the full-frontal crash testing of the FSW and GMAW fabricated bumper using experimental method is presented. The FSW and GMAW fabricated bumpers are subjected to 7, 10, 15 and 20 km/hr impact velocities against a rigid wall. The methods used to quantify the results are the post-crash deformation and stress distribution of the bumper as well as crack propagation at the weld joint. The non-linear dynamic software, LS-DYNA, is used exclusively in the second part of this study to replicate the experimental procedures using numerical methods. Finally, a 40% frontal offset test is conducted to evaluate the performance of the bumper when subjected to a different impact condition. It was shown that the FSW fabricated bumper can enhance the structural integrity and performance of the bumper at all impact velocities and configurations.

Keywords:

• friction stir welding
• gas metal arc welding
• crack propagation
• full-frontal test
• 40% offset test
• LS-DYNA
• crashworthiness
• road vehicle bumper
• structural deformation

Acknowledgements

This research would not have been possible without the support of Dr. Blair Carlson and General Motors Corporation, Michigan, USA. Special thanks to members of the Advanced Joining and Processing Lab (AJPL), National Institute of Aviation Research (NIAR) and Wichita State University (WSU) for assisting in various testing processes.