On the piercing force enhancement of aluminum foam sandwich plates under impact loading

This article tends to explain the observed piercing force enhancement under impact loading of the sandwich panels, which is made of rate-insensitive aluminum skin sheet and Cymat foam core. Using an elastic–plastic damageable model for the skin and an isotropic foam constitutive model for the core, a numerical model is proposed and validated by the comparison with experimental results. Virtual tests allow revealing that the damage evolution in the skin sheet is strain rate dependent because of the wave propagation effects. Under impact loading, the damage area is larger and it leads to a larger deflection of the skin plate at its breaking. Therefore, the foam cores are more compressed under impact loading and induce the piercing force enchancement of the sandwich.