The Perforation Resistance of Aluminum-Based Thermoplastic FMLs

The perforation resistance of fibre metal laminates (FMLs) made of an S-glass fibre reinforced poly-ether-ketone-ketone (GF/PEKK) composite and an aluminium alloy (2024-T3) is investigated. Initial attention is focused on assessing the effect of the processing temperature on the tensile strength of the aluminium alloy. Here, it has shown that the processing cycle results in a reduction of approximately 35% in both the tensile strength and yield strength of the aluminium alloy. A comparison of the quasi-static and dynamic perforation responses of the FMLs highlighted the rate-sensitivity of these laminates, with the perforation energy increasing as the loading rate varies from quasi-static to impact. After testing, the FML specimens were sectioned to highlight the prevailing failure modes. An examination of the cross-sections indicated that the impact energy of the projectile is absorbed through plastic deformation and tearing of the metal layers, delamination between the composite plies and metal layers as well as fibre fracture. Finite element models (FEM), using ABAQUS/Explicit, have been developed to predict the behaviour of the FMLs subjected to dynamic loading. The outputs of the FE models were then validated against the measured experimental force-displacement traces and the observed failure modes. The results of the FE models were in a good agreement with the experimental data, in terms of the initial stiffness, maximum force and maximum displacement, as well as the perforation mechanisms.

Automated summary

The study investigates the perforation resistance of FMLs made of GF/PEKK composite and aluminium alloy. It found that processing temperature affects the tensile strength of the aluminium alloy, and that FMLs exhibit rate-sensitivity under dynamic loading, absorbing impact energy through plastic deformation, tearing, and delamination. Finite element models accurately predicted the behavior of FMLs and matched experimental results in terms of stiffness, maximum force, displacement, and perforation mechanisms.