Improvement

The complicated nature of the physical crash processes of complex vehicle structures makes design optimization for crashworthiness a very challenging task. Moreover, large scale and highly nonlinear nature of crashworthiness simulations of vehicle struc-ture make it impractical to conduct direct optimization on the full nonlinear model of the structure. The main objective of the thesis is to present a systematic and prac-tical methodology to conduct vehicle crashworthiness design optimization efficiently at early stages of design. The thesis includes four main parts. In the first part, an efficient and practical methodology for design optimization of vehicle structures under frontal impact for crashworthiness improvement is presented. The proposed methodology is based on identifying the main vehicle structural part contributing most to the total amount of impact energy absorbed in the whole vehicle structure. The computationally efficient surrogate model of expensive nonlinear finite element simulation of this major vehicle part is developed and then integrated with gradient based optimization algorithm to maximize its absorbed impact energy while guard-ing against increase in its weight. In the second part, a methodology for deriving th