Plastic deformation and energy absorption of polycrystalline-like lattice structures

Abstract

Polycrystalline-like (PL) lattices are potential energy-absorbing structures composed of basic periodic mono-crystals arranged in different orientations. A series of numerical simulations were conducted to investigate the in-plane crushing resistance and energy absorption of different polycrystalline-like lattice structures. The finite element modelling (FEM) results clearly reveal that the PL lattice structures provide more excellent impact resistance and energy absorbing efficiency compared with conventional monocrystalline (MC) lattices. Compared with the four-cell ML lattice structure, the nine-cell PL lattice structures improve the mean crushing force (MCF) and specific energy absorption (SEA) by 1.5 times, and can effectively suppress the growth rate of the initial peak force (PF). The improvements in the MCF and the SEA originate from the grain boundaries of the PL lattice structures which restrain the evolution of the shear bands and change the shear failure mode of the MC lattice structures into a layer-by-layer progressive crushing mode.

Keywords

• Polycrystalline-like lattice structure
• Plastic deformation
• Energy absorption
• Grain boundary effect