Shock enhancement in cellular structures under impact loading by finite element simulation

Abstract

In recent years, strength enhancement of cellular structures under impact loading has been found by some scientists during experiments. However, the influence of the impact velocity and relative density of the materials on the shock enhancement has seldom been studied. In this paper, the impact response of aluminium foam and its dependence on relative density and impact velocity are analysed using the finite element method. The simulation results show that at the 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 with both impact velocity and relative density.

Keywords:

• Aluminium foam
• Shock wave
• Critical impact velocity
• Finite element method

This work was supported by the National Science Foundation of China (grant no. 10932008 and no. 10902090), Basic Research Foundation (grant no. JC201001) and 111 project (grant no. B07050) of Northwestern Polytechnical University.