Crashworthiness topology optimization of bone-like porous structures

Porous structures exist widely in biological materials. In this study, a new topology optimization method is developed to generate bone-like porous structures with high crashworthiness. In this method, the design space is divided into a certain number of subdomains, and the material layouts in different subdomains are controlled separately. A mapping approach is proposed to further improve the crashworthiness of the optimized structures. A subdomain-based parallel strategy is adopted to accelerate the form-finding process. A weighting strategy is adopted to produce structural designs with easily tunable mechanical properties. Drop-weight impact tests were performed to measure the mechanical responses of the optimized structures. The effectiveness of our method is demonstrated through both experimental and numerical results. It is found that stress distributions in the optimized porous structures are insensitive to the external loads. As the number of holes increases, the high-stress regions of the structures decrease. This work not only paves a way for the crashworthiness design of high-performance engineering structures, but also provides a tool for exploring the structure–property interrelations of biological porous materials.