Optimization of Longitudinal Beam for Improvement of Crashworthiness in Frontal and Offset Impacts

The aim of the study is to optimize the longitudinal beam based on 100% overlapping rigid barrier ( 100% RB ) impact and 40% overlapping offset deformable barrier ( 40% ODB ) impact. The 100%RB and 40%ODB impact FE models were developed in LS-DYNA and validated by using results from crash tests. According to the requirement of crashworthiness, the peak of acceleration of left B-pillar and energy absorbed per unit mass of longitudinal beam were chosen as optimization objects, and the thicknesses of four parts of the longitudinal beam were considered as the design variables. Furthermore, uniform design was applied to build variable samples. Optimal results were obtained by surrogate model built by Kriging and optimization method NSGA-II (Non-Dominated Sorting in Genetic Algorithms-II). The results showed that 100%RB and 40%ODB impact should be considered together when longitudinal beam was designed. The optimized longitudinal beam matches well and effectively improves vehicle crashworthiness.