Multi-objective crashworthiness optimization of square aluminum tubes with functionally graded BCC lattice structure filler

The objective of this study is to find the optimum design configurations for the crashworthiness of functionally graded lattice structure filled aluminum tubes under multiple impact loading conditions. Base strut diameter, draft angle and aspect ratio are considered as filler material design parameters, and the optimal design configurations are sought for maximizing the specific energy absorption and minimizing the peak crush force. The finite element simulations are performed to establish the sample design space; linear and non-linear least square regression meta-models are developed to estimate the objective function values; the weighted superposition attraction-repulsion algorithm is employed to create design alternatives and seek their optimum combinations. The compromise programming technique is also adapted for combining multiple objectives and generating different optimum design options. The results revealed that the proper selection of design parameters can effectively enhance the crashworthiness performance of hybrid structures under multiple impact loading conditions. In particular, the results showed that the specific energy absorption value of square tubes can be improved up to 76% with the selection of appropriate lattice filler parameters. The present study provides a guideline for the optimum design of functionally graded lattice structure filled thin-walled structures under multiple impact loading conditions.