Damage in preloaded glass/vinylester composite panels subjected to high-velocity impacts

This paper examines the influence of in-plane preloading on the damage of thin composite panels under high-velocity impact loading. The composite was a tape laminate made with a glass-fibre and vinylester matrix. Impact on a preloaded laminate was analysed experimentally, comparing their behaviour with the condition in which the laminate was load-free. Two preload cases representative of actual structures were selected, uniaxial and biaxial load cases. An experimental device was developed to apply the load in two perpendicular directions. This device was combined with a gas gun to carry out impact tests in a broad range of impact velocities. The static preload altered the perforation-threshold velocity and the damage area in the laminate. Decrements of the both variables were detected in the preloaded specimens, both with uniaxial and biaxial loads. The reduction of the damage area was greater for impact velocities close to the perforation-threshold velocity in all the cases analysed. (C) 2013 Elsevier Ltd. All rights reserved.