Finite element simulation of shock enhancement in cellular structures under impact loading

In recent years, the strength enhancement of cellular structures under impact loading has been found by some scientists during experiments. But the influence of the impact velocity and relative density of the materials on the shock enhancement was seldom studied. In this paper, the impact response of aluminium foam and its dependence on relative densityand impact velocity are analyzed using Finite Element Method (FEM). The simulation results show that under large impact velocity, the elastic wave as the pioneer goes through the whole sample and makes the sample equilibrating. When the stress exceeds the plateau stress of the material and makes it densified, the shock wave will be generated and lead to stress unequal at the two ends of the specimen within a certain period. Shock enhancement of the cellular structure becomes more significant with lower relative density and high impact velocity. The estimated shock front velocity increases withboth impact velocity and relative density.