Impact responses of heat-treated functional graded 3D printed gyroid lattice structures

Abstract This paper investigates the design and mechanical behaviour of AlSi10Mg gyroid lattice structures under dynamic loading conditions. Triply periodic minimal surface (TPMS) gyroid lattices are generated based on the level-set approximation method and fabricated through powder bed fusion (PBF) with heat treatment. A numerical model is developed and validated by low-velocity impact drop-weight compression tests. High strain-rate-dependent materials model is investigated numerically following the validation of low velocity impact test. While local material could experience strain-rate effect, overcall lattices experience negligible influence of strain-rate. The study focuses on predicting deformation modes and the compressive response under impact loads using drop-weight tests and numerical simulations. Three distinct modes: homogeneous, transition, and shock are identified, each marked by different force-displacement behaviours and deformation behaviours. It is found that relative density significantly impacts mechanical performance, with higher densities leading to increased peak and mean crushing forces and more stable force-displacement curves. The structure with a graded relative density demonstrates improved deformation uniformity and stress distribution. The continuum-based shock model accurately predicts critical impact velocities corresponding to different deformation modes.