System reliability based vehicle design for crashworthiness and effects of various uncertainty reduction measures

Reliability-based design optimization of automobile structures for crashworthiness has been studied by many researchers by using either single component probabilistic constraints or single failure mode based probabilistic constraints, while system reliability considerations are mostly disregarded. In this paper, we perform system reliability based design optimization (SRBDO) of an automobile for crashworthiness and analyze the effect of reliability allocation in different failure modes. In addition, effects of various uncertainty reduction measures (e.g., reducing variability in material properties, reducing error of finite element analysis) are investigated and tradeoff plots of uncertainty reduction, system reliability and structural weight are generated. These types of tradeoff plots can be used by a company manager to decide whether to allocate the company resources for employing uncertainty reduction measures or allocating the resources for the excess weight to protect against the unreduced uncertainties. Furthermore, relative importance of automobile structural members in different crash scenarios is quantified.