Crushing response and multi-objective optimization of a novel double-feature bio-inspired gradient lattice structure under dynamic loading conditions

Abstract

To meet the impact requirements of lightweight lattice structure under varying orientations, inspired by the bidirectional gradient distribution characteristics of spider webs and the excellent impact resistance of the peacock mantis shrimp, a novel double-feature bio-inspired gradient lattice structure (DBGLS) was proposed in the study. By combining the bionic gradient structure with the bionic lattice structure, DBGLS can realize the synergistic mechanism of various bionic characteristics, enhancing impact resistance and energy absorption under multi-angle loads. A finite element simulation model for DBGLS is established, and 3D printing technique is utilized to manufacture test specimens for quasi-static compression tests to validate the simulation model’s accuracy. Afterwards, the stress distribution, deformation, load capacity, and energy absorption of DBGLS under multi-angle impact loading are systematically analyzed. Relying on the simulation results, response surface methodology (RSM) and second-generation non-dominated ranking genetic algorithm (NSGA-II) are applied to perform multi-objective optimization on DBGLS. The results indicate that the DBGLS outperforms the uniform and single gradient structures in bearing capacity and impact resistance under axial and oblique loads. Among them, the DBGLS with a negative lateral gradient and positive longitudinal gradient exhibits the highest specific energy absorption, 36.84 % higher than the uniform structure. The optimal design parameters of DBGLS are obtained through multi-objective optimization. The optimized DBGLS demonstrates a 40.07 % increase in specific energy absorption and a 24.90 % reduction in initial peak force compared to the original structure. This study provides new insights for designing bionic gradient lattice structures under complex loading conditions.