Isotropic design and mechanical characterization of TPMS-based hollow cellular structures

Abstract

Isotropy is an excellent characteristic for load-bearing and energy-absorption that ensures the cellular structures respond uniformly under external loads in all orientations. This paper presents an isotropic design method for the triply periodic minimal surfaces (TPMS)-based cellular structures with both superior load-bearing and energy-absorption capacity. The design strategy is realized by performing the Boolean operation on TPMS with different level parameters to obtain a hollow design. The level parameters of the hollow cellular structures are the design variables. The Zener ratio is introduced to characterize the isotropy of cellular structures based on the numerical homogenization results. The isotropy optimization model of the cellular structure is established to minimize a residual function. The genetic algorithm is then applied to solve the optimization model to obtain the isotropic hollow cellular structures. The numerical homogenization and finite element analysis are further conducted to analyze the static mechanical performance of the optimized hollow cellular structures. The mechanical experiments are finally carried out to reveal the dynamic compression properties and energy-absorption characteristics. Compared with the solid counterparts, the optimized isotropic hollow cellular structures have higher Young’s modulus and bulk modulus, and better load-bearing and energy absorption properties.