On the crushing response of the functionally graded metallic foams based on 3D Voronoi model

This paper presents the study on crushing response of functionally stepwise graded foam under quasi-static and dynamic compression using three-dimensional (3D) Voronoi model. A series of simulations is conducted to acquire proper computing parameters and to validate the predictability of numerical model by comparing with experiment results. Two different strategies are proposed to achieve the gradient change in relative density by changing equivalent radius and cell-wall thickness. The main focus of present paper is placed on the effect of gradation configuration on the stress-strain response, deformation propagation and energy absorption. The results show that the gradation configuration has little effect on the crushing behavior of graded foams under quasi-static compression. However, the performance of graded foam under dynamic compression could be promoted by tailoring its gradation configuration. Adopting a negative gradation is beneficial for reducing the stress at the stationary side and maximizing the energy absorption under low strain level. A positive gradation would be preferred as an energy absorber under high strain level. • The mesostructure of functionally graded metallic foams is constructed by using 3D Voronoi model. • The crushing responses of graded foams under quasi-static and dynamic compression are investigated. • Comparison between two different strategies for achieving the gradient change in relative density is conducted. • The effect of gradient on the stress-strain response, deformation propagation and energy absorption is elucidated.