Study on design and impact energy absorption of network Voronoi lattice structure with directional regulation of load transfer paths

Current designs of irregular structures generated by Voronoi-Tessellation focused on improving performance under specific working conditions. The purpose of this study was to design a series of network Voronoi lattice structures to enhance their comprehensive impact energy absorption and stable deformation under multiple working conditions through directional regulation of load transfer paths of struts. Under different compressive angles and velocities, the mechanical responses and deformation modes of network Voronoi lattice structures manufactured by multijet fusion were investigated through the mechanical test and simulation. Regression equations were established by response methodology to determine the relationships between network Voronoi unit cell design parameters and structural mechanical parameters. Finally, the energy absorption of new bicycle helmet filled with optimal network Voronoi lattice obtained by multi-objective optimization was investigated by simulation. Results indicated that the mechanical parameters of network Voronoi lattice structures were improved with increase of compressive velocity and were decreased with increase of compressive angle. The axial and oblique compressive deformations of structures were dominated by quasi-static mode at low velocities and the “shock wave” mode at high velocities. Compared with typical bicycle helmet liners filled with other porous structures, the bicycle helmet liner filled with the optimal network Voronoi lattice was characterized by lightweight and high comprehensive impact energy absorption. In this paper, a series of network Voronoi lattice structures were designed based on load transfer paths. It provided a feasible design solution and theoretical basis for the optimal design of impact resistant protective structures under multiple working conditions.