Mechanical and energy absorption properties of functionally graded lattice structures based on minimal curved surfaces

Abstract

Compared with uniform structures, functionally graded lattice structures can control mechanical properties through varying structures and their volume fraction. In this study, a three-period minimal curved surface method was used to generate functional lattice structure with linear or quadratic function (LF or QF) gradient strategy in the forming direction, and the samples were fabricated by selective laser melting (SLM) using the Ti-6Al-4V metal powder. The mechanical properties, deformation behaviors, and energy absorption performance of graded lattice structures, LF, and QF I-Wrapped Package (IW-P) lattice structures were systematically investigated through experiment and finite element analysis (FEA). Based on the experimental and numerical simulation results, the LF lattice structure shows higher elastic modules and yield strength during small strain period. And the merits of performance increased layer-by-layer under large strain. Additionally, the simulation results based on Johnson-Cook and failure model show that this model can reflect structural compression deformation behavior and mechanical performance prediction. Furthermore, the elastic modulus of LF lattice structure is higher than uniform lattice structures by nearly 61.52% under the same lattice volume fraction. Compared to other lattice structures, the LF or QF lattice structures have better support performance under small strain and stronger energy absorption capacity under large strain with the same volume fraction, respectively, which shows superior potential to be applied to manufacture protective devices or vibration damping devices.