Mechanical properties and energy absorption capabilities of functionally graded lattice structures: Experiments and simulations

Abstract

Functionally graded lattice structures are characterized with their varied structures and mechanical properties, which leads to better mechanical performance comparing to the uniform structures. In this paper, a series of cells with different densities and configurations were formed by changing the unidirectional size of a uniform lattice cell, and then assembled into a size-graded (SG) lattice structure with varied densities and topological configurations. Experimental samples were manufactured from PA2200 by selective laser sintering (SLS) and then tested by a quasi-static compression experiment. Based on the experiment and numerical simulation results, the compression responses and the influence of its graded orientation on the structure performance were investigated. The results show that the SG structure is connected stably and owns the merits of high modules and strong strength under small strain, and characteristics of performance enhanced layer-by-layer under large strain. Therefore, it has better support performance under small strain and superior energy absorption ability under large strain compared with other structures, which indicate its feasibility of being applied in protective devices with impact resistance properties.