High-velocity impact behaviour of damaged sandwich plates with agglomerated cork core

Abstract

Damage can significantly modify the behaviour of composites laminates subjected to high-velocity impacts. Due to the high energy-absorption capability and low density of agglomerated cork, a possibility to reduce the impact damage, and improve the impact resistance of composites structures, is to incorporate a layer of this material as core of a sandwich structure. In this work, an experimental analysis of ballistic impact behaviour of damaged monolithic laminates and composite sandwich plates, with agglomerated cork core, was carried out. First, both types of specimens were damaged by a low-velocity impact at two impact energies. In order to ensure that the resulting damage was different, typical low-velocity impact variables were analysed. Later, reference (intact) and damaged specimens were subjected to ballistic impacts. For intact specimens, no significant differences between the impact behaviour of sandwich plates and laminates were observed. Nevertheless, the ballistic limit per areal density of damaged laminates was reduced when compared to the value given for reference laminates, whereas in sandwich structures it was almost constant.