Investigations on the impact behaviour of fibre-reinforced composites: Effect of impact energy and impactor shape

In the present research, a detailed experimental study of the impact behaviour of CFRP composites is performed. To investigate the effects of impactor velocity, a round-nosed steel impactor is employed to strike the composite specimens at two impact velocities (i.e. 2.40 m.s^-1 and 4.16 m.s^-1). To investigate the effects of the geometry of the head of the impactor, a flat-faced steel impactor is also employed to strike the composite specimens at a velocity of 2.40 m.s^-1. After the impact experiments, all the tested composite specimens are inspected using a C-scan device to assess the damage due to the different types of impact. The experimental results, including the loading response and impact-induced damage, are employed to analyse the effects of impact velocity and impactor shapes on the impact behaviour of the composite laminates. The results indicate that, at the higher impact velocity (i.e. 4.16 m.s^-1), delamination is more extensive near the rear face of the composite, whilst the delamination near the front face is less sensitive to the increase in the impact velocity. For the lower impact velocity (i.e. 2.40 m.s^-1), the area of the damage footprint from the round-nosed steel impactor and the flat-faced steel impactor are similar in extent, but the shape of the damage footprint is very different. The round-nosed steel impactor causes a centrally symmetric damage area, whilst the flat-faced steel impactor causes damage in which the central area shows much less damage.