The low velocity impact response of curvilinear-core sandwich structures

• Impact perforation failure of curvilinear corrugated-core sandwich structures.
• Finite element modelling of impact response of the sandwich panels.
• The failure mechanisms of the impact-loaded corrugated structures.
• Parametric studies on projectile size, material type and the angle of impact.

The low velocity impact response of lightweight aluminium sandwich panels, based on a curvilinear aluminium alloy core, has been investigated to evaluate their energy-absorbing characteristics and to identify the associated failure mechanisms. Finite element models are then developed to predict the dynamic response of these lightweight structures. Here, an elasto-plastic model, capable of accounting for strain-hardening effects, material rate-dependence, as well as the relevant damage criteria, was employed to predict the dynamic response of the targets. The finite element models were then validated by comparing their predictions against the corresponding experimental results. Good agreement was obtained, indicating that the models are capable of predicting the dynamic behaviour of these all-metal sandwich structures under low velocity impact conditions.Once the finite element model had been validated, it was used to assess the effect of varying key test parameters, such as the projectile diameter, the material properties of the metal substrate as well as the angle of obliquity on the impact response. Here, it has been shown that the perforation energy increases as the impact angle is increased and also as the projectile diameter increases. An investigation of seven different all-metal sandwich structures has shown that an aluminium alloy offers the highest specific perforation resistance under conditions of low velocity impact loading.