Optimization for energy absorbing crash box under frontal impact 2019-01-1432

The modern vehicle structure requires considerations in crash safety and lightweight design when compared with the conventional one. In the present exposition a key concept of vehicle safety design at a component level, i.e. a crash box, under impact loading is considered. Finite element based crash analysis was used as a tool for geometric design. The double-hat section, spot-welded mild steel of crash boxes was investigated to determine the peak load, mean crushing load and energy absorbing. The main objective was to optimize the taper angle and the wall thickness as design variables to improve the weight and the crash performance. Material properties and stress-strain relations in various strain rate were obtained by the standard testing and by experiment validation to ensure finite element modeling. Meanwhile physical tests were carried out with both quasi-static and dynamic impact conditions in order to validate the baseline model of the crash box prior to shape optimization. The influence of design variables were summarized and indicate significant improvement in the crash test over the baseline design.