The influence of acrylate triblock copolymer embedded in matrix on composite structures’ responses to low-velocity impacts

In passive safety structures the use of composite materials has increased significantly recently due to their low specific mass and high energy absorption capacities. The purpose of this experimental study is to describe the macroscopic behaviors of different Kevlar woven composite materials with different kinds of matrix (pure and with acrylate based block copolymer additives: Nanostrength®) under low-velocity impact. Tests were performed with a drop weight tower on square plates (100 × 100 mm2) clamped by means of a circular fixture. Images were recorded during impact by a high-speed video camera fixed underneath the plate. It was found that Kevlar epoxy composite material with Nanostrength M52N has the best resistance to perforation.The second purpose is to study the influence of physicochemical parameters (fibers ratio, percentage of M52N, micro-porosity) on the behavior of the selected composite material. Based on correlation between pictures, displacement, and loading histories, two criteria are defined to quantify the energy absorption capability of the composite material just before the fibers’ failure and after perforation of the plate. A high-fiber weight improves performance regarding criteria and also improves the efficiency of the block copolymer present in the epoxy matrix.