In an automotive product development environment, identifying the premature structural failures is one of the important tasks for Body-In-White (BIW), sub-assemblies and components. The integrated car body structure i.e. monocoque structure, is widely used in passenger cars and SUVs. This structure is subjected to bending and torsional vibrations, due to dynamic loads. Normally the stresses due to bending are relatively small compared to stresses due to torsion in Body-In-White under actual road conditions [1]. This paper focuses on evaluating the life of Body-In-White structures subjected to torsional loading.
An accelerated test method was evolved for identifying failure modes of monocoque BIW by applying torsion fatigue. The observation of the crack generation and propagation was made with respect to a number of torsion fatigue cycles. Location correlation was carried out by comparing failure modes of BIW at laboratory test and failure modes of BIW at vehicle level accelerated test arising due to BIW torsion.
The road testing requires longer time and greater costs than laboratory testing [1]. In vehicle development process, BIW is developed at an earlier stage. By applying the generic load cycle, the weaker zones and failure modes of Body-In-White (BIW) can be identified at an early stage of vehicle development process and thereby reduce iterations.