Review of CAE Fatigue Analysis Techniques for Spot-Welded High Strength Steel Automotive Structures

Durability assessment of automotive structures with resistance spot welds is an important part of automotive development. Down-gauging of vehicle body structures permitted by high strength steels brings added challenges to joint design. As a result, more accurate fatigue life analysis of joints is called for by automotive engineers, especially as part of the computer-aided engineering (CAE) evaluations in the early stage of model development.

This paper will review, evaluate and compare spot-weld fatigue assessment techniques suitable for use in the CAE environment. Particular attention is paid to the process of generating technique-specific spot-weld fatigue property curves. The focus is then switched to two of the most promising techniques, which are evaluated in detail. The validity of the two techniques and the associated fatigue data are then demonstrated on fatigue life predictions of simple and complex components. Practical issues related to the proper use of the techniques are discussed. Comments are made on the advantages and disadvantages of each technique. Finally, areas of improving the CAE durability tools for welded vehicle structures are proposed.