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The low-velocity impact response of a series of glass fiber reinforced epoxy/aluminum alloy fiber metal laminates has been investigated. The influence of varying target thickness, plate diameter, and impactor radius has been studied and the results compared to those offered by plain composite samples. After testing, many samples were sectioned in order to highlight the failure modes under low-velocity impact loading. The FMLs absorbed significant energy in plastic deformation, tearing the metal layers and fiber fracture, and offered a superior impact resistance to the plain composite on which the FMLs were based. The perforation data were normalized by the areal density of the target and the superiority of the metal—composite hybrids remained in evidence. Increasing the target size, the plate thickness, and the indentor diameter resulted in an increase in the energy required to perforate the target. In contrast, impacting the square panels at the corner or along the edge of the target did not have a significant effect on the perforation response of the structures.

In this article, experimental results are presented investigating the response of glass fiber composites subjected to low velocity impact loading. The resulting load‐displacement traces and deformation modes have been used to validate a number of numerical models. Here, finite element models have been developed to predict the impact behavior of the composite plates. Damage in the woven glass‐fiber reinforced composite plate was modeled using the Hashin failure criteria. The influence of target size, projectile size, projectile shape, and striking location on the impact response of the composites was investigated. In general, good agreement was obtained in terms of the load‐displacement traces and the failure modes in the composite plates. It has been shown that the perforation energy increases rapidly with target thickness, with the numerical results closely agreeing with the experimental data. Similarly, the energy required to perforate the composite targets increases with increasing projectile diameter, with the failure mechanisms being similar in all cases. Finally, increasing the bluntness of the impactor resulted in a significant increase in the energy to perforate these targets. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact, which produced the corresponding load-displacement traces and deformation/failure modes for the validation of numerical models. Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested. The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage, followed by shear failure and tensile failure to simulate its failure mechanisms. The glass fibre laminate (woven glass-fibre reinforced composite) layer was modelled as an orthotropic material up to its on-set of damage, followed by damage initiation and evolution using the Hashin criterion. The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests. The damage evolution was controlled by tensile/compressive fracture energies combined with both fibre and matrix. The FE models developed for the 2/1, 3/2 and 4/3 FMLs plates made with 4-ply and 8-ply glass fibre laminate cores were validated against the corresponding experimental results. Good correlation was obtained in terms of load-displacement traces, deformation and failure modes. The validated models were ready to be used to undertake parametric studies to cover FMLs plates made with various stack sequences and composite cores. damage, Hashin criterion, finite element, impact, FMLs, progressive failure

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