The effect of middle layer material and thickness on the quasi-static energy absorption of FML

In the present study the effect of change in thickness and material of the middle layer in fiber metal laminates (FMLs) with squared section on the energy absorption is investigated. In this work four types of specimens, based on the change in the material of the middle layer, were produced. In order to fabricate FML samples, Glass-epoxy, Carbon-epoxy, polyurethane foam and aluminum 2024 were utilized as the middle layer and aluminum 2024 for inner and outer layers, respectively. The specimens were then subjected to the compression test and their force-displacement curves were experimentally obtained. Additionally, the effect of the middle layer thickness on the energy abortion performance was studied by numerical simulation using Ls-Dyna explicit code. The numerical model was initially validated by experiment. In conclusion, it was found that the maximum and minimum efficiency were determined for the FML specimen made of Carbon-epoxy and foam, respectively. Moreover, by changing the middle layer thickness, it was numerically demonstrated that the specimen with three layers of the same thickness yields the best absorption energy capability.