Numerical and Experimental Investigation of Density Graded Foams Subjected to Impact Loading

Cellular materials offer many advantages due to their higher energy absorption capacity and strength for a given weight. The energy absorption performance is dependent on material density. Different density foams can be tailored and graded in a structure so that the merits of both low density and high density foams can be exploited. In this work, density graded polymeric foams with different configurations are examined, and their response to impact loading is studied both numerically and experimentally. Two-dimensional cell-based finite element model is developed for modeling the dynamic response of foams with different density gradation in Abaqus, a commercial finite element software. Three different types of foam structures are studied. Each of the foam structures is made up of three different density layers. The experimental investigation is also carried out on a gas gun setup incorporating high-speed imaging and is used to verify the numerical results. The stress-strain curves and the energy absorption characteristics of different graded foam structures are evaluated. It is found that the graded foam structure with higher density layer on the impact side absorbs more energy than the uniform foam structure at lower strains.