A nano-scale material model applied in finite element analysis of aluminium plates under impact loading

Finite element simulations of AA6070 aluminium plates struck by ogival-nose projectiles are performed. The aluminium plates are 20 mm thick and heat treated to temper O, T4, T6 and T7. A nano-scale material model, consisting of three parts: a precipitation model, a yield-strength model and a work-hardening model, is used to predict the flow-stress curves of the materials at ambient temperature based on the chemical composition of the alloy and the thermal history defined by the heat treatment. Finite element simulations of the perforation process are then carried out using both 3D solid and 2D axisymmetric elements. The numerically-obtained ballistic limit velocities, predicted without any use of data from mechanical tests, are compared with available experimental data and found to be in good agreement with the experimental ones for all tempers. The same holds for the predicted residual velocities at striking velocities higher than the ballistic limits.