Effects of ballistic impact damage on mechanical behaviour of composite honeycomb sandwich panels

This paper presents the effects of ballistic impact damage on the mechanical behaviour of composite honeycomb sandwich panels. The panels are composed of facesheets made of carbon fibre reinforced laminates and the Nomex honeycomb core. Ballistic tests were conducted in a shooting range using live projectiles of three different calibres. The specimens were subjected to both normal and oblique impacts to simulate the damage to composite sandwich structures that can be inflicted by the use of small weapons or by fragments of anti-aircraft ammunition. The modes and extent of the damage induced have been analysed using optical microscopy, X-ray inspections and computer tomography methods. Structural performance of the intact and ballistically damaged panels has been investigated experimentally using in-plane compression tests, and numerically, based on the finite element modelling and analysis. The reduction in the load-carrying ability caused by the ballistic damage has been assessed for the panels under consideration and compared with that predicted by numerical simulations.