Effect of tensile preloading on the ballistic properties of GFRP

Abstract

This paper focuses on a ballistic impact response of composite plates with a thickness of 2 mm subjected to uniaxial tension preload. It also presents experimental and numerical results of ballistic impact response studying. To generate impact damages by a spherical projectile in the range of 100–800 m/s velocities the powder gun stand was used. During the experiments, the ballistic stand was placed in an INSTRON 5882 testing machine for setting five different states of preloading. The results showed that uniaxial tension preload reduces the ballistic limit. Higher tensile preload levels were found out to lead to the smaller delamination area. This is a result of impact energy dissipation in inclined (and damaged during pretension) segments of threads which play the role of dry friction contact areas between fibres. The response time to the rupture of the specimen after penetration depends on a preload level, which was observed as another phenomenon. The finite element simulations of preloaded plates subjected to ballistic impact were carried out using ANSYS Workbench (AUTODYN3D) explicit package. As numerical results were in good agreement with the experimental data, a variation of GFRP ballistic limit with tension up to 92% of strength was numerically investigated.