Novel Negative Poisson's Ratio Lattice Structures with Enhanced Stiffness and Energy Absorption Capacity.

The weak stiffness and strength of materials with negative Poisson's ratio limits their application. In this paper, three types of novel lattices with negative Poisson's ratio are proposed to improve not only stiffness and strength but also energy absorption capacity by embedding different ribs into a classic re-entrant structure. Unit cell analyses show these novel lattices have significantly increased Young's modulus along the loading direction, and Type C can maintain sufficient negative Poisson's ratio performance compared with the base lattice. In addition, the novel lattices exhibit higher yield stress, plateau stress and densification strain extracted from quasi-static compressive simulation. The lattices are prototyped by laser-based additive manufacturing and tested in quasi-static experiments, which show the experimental data match the numerical results within an error of margin. The work signifies the prospect of lattices with negative Poisson's ratio in enhancing engineering-applicable structures, and indicates the potential of structural topology optimization in more sophisticated designs.