Experimental and numerical investigation of nano-reinforced elastomeric fiber metal laminates subjected to high strain rate loading

In this study, the high-velocity impact response of an elastomeric fiber-metal laminate (EFML) comprising aluminum, glass/epoxy, and a natural-rubber elastomer reinforced with nano-alumina was investigated. Ten nano-alumina contents (0, 0.5, 1, 2, 3.5, 5, 10, 15, 20, and 25 wt.%) were considered to evaluate their influence on the dynamic response. Split Hopkinson pressure bar (SHPB) tests were used to identify concentration-specific hyperelastic coefficients, and gas-gun tests on the alumina-free laminate were used to validate the numerical impact model. The elastomer was represented in LS-DYNA using Mooney-Rivlin, Neo-Hookean, and Blatz-Ko models, with parameters fitted to the SHPB data. The simulations agreed satisfactorily with the measured residual velocity and observed damage modes of the alumina-free laminate. The validated model then predicted the response of the nano-alumina-containing laminates. The numerical results indicated lower residual velocity and greater energy absorption at 1, 10, and 15 wt.% nano-alumina; these formulation-dependent trends are numerical predictions because corresponding high-velocity impact tests were not performed for the filled laminates. Increasing nano-alumina content also modified load transfer to the distal composite and aluminum layers and increased their displacement. These results clarify the predicted influence of nano-alumina content on the impact response of the investigated EFML.