Structural Durability Enhancement through Spot Welds – An Automated Methodology 2004-01-0879

Structural durability is one of the key factors in determining the robustness of a product having a direct bearing on customer perception of quality and reliability in passenger vehicles, and is one of the major factors affecting customer loyalty.

It is recognized that significant fatigue failures occur at spot welds in an automobile body structure, and accordingly various methods are adapted in the industry to predict such failures. However, most of them follow the traditional fatigue and fracture analyses, which are computationally challenging, expensive as well as mathematically complex to apply on a full vehicle system. As a result, most of these methods depend on iterative solutions e.g. Design of Experiments.

An indigenous method of evaluating failures at welds and/or their vicinity and their implication on the structural failure and life is developed [1] which is incorporated into a user friendly computational environment for assisting product designers to design spot weld layouts for efficient load transfer as well as improved structural life. The method is based on a family of indigenously developed set of rules based on strength, compliance and failure modes as well as an ever growing set of heuristics based on experience in the field. The method is simple to use as it is based on the popular finite element models and their linear solutions (static, eigen and forced response). In this paper, a brief overview of the method is presented from durability perspective followed by some typical results from some typical automotive structural assemblies.