Mechanical Behavior of Composite Sandwich Structures Subjected to Low Velocity Impact – Experimental Testing and Finite Element Modeling

Abstract

Sandwich materials with a cellular foam core are increasingly used in engineering applications. The basic advantage of these materials is their high strength-weight ratio. However, sandwich structures are notoriously sensitive to failure by the application of highly localised external lateral loads. Therefore the proper design requires an understanding of the response of these materials to localised loads. The purpose of this work was the evaluation of the low velocity localised impact behaviour of sandwich structures made of glass-fibre reinforced composite laminate face sheets and polyvinylchloride (PVC) foam core. The impact tests were performed with a drop-weight rig. Beam and panel sandwich specimens were impacted using steel cylindrical and spherical impactors, respectively. During the testing, the specimens were supported by a stiff steel continuous substrate in order to avoid global bending. The load and deceleration histories were recorded during impact. A finite element model was developed to simulate the impact response. Results obtained by this model exhibit good correlation with the experimental data. It is shown that the model can be used to successfully predict the elastic-plastic response of sandwich composite structures subjected to low velocity localised impact.