Ballistic resistance of 2D and 3D woven sandwich composites

In the present study, the ballistic resistance of sandwich composite structures for vehicle armor panel applications is investigated. The core material of each sandwich structure is a layer of tiled alumina ceramic, combined with a layer of two-dimensional (2D)/three-dimensional (3D) S-2 glass-based woven composite laminate, sandwiched between 2D plain weave composite skins. The 2D composite backing consists of a plain woven fiberglass, with fiber orientation predominantly in the direction of plane of the weave. The 3D contains similar in-plane fiber preform structure, with the inclusion of an integral through thickness fiber, creating a 3D structure. The ballistic performance of sandwich composite with several types of 3D woven backings is compared to the baseline 2D plain weave backed sandwiched composites. An IMACON 200 high-speed camera is used to obtain high-speed photographs of the ballistic events of penetration and damage. These images are analyzed to study the real-time damage mechanism of the strike face surface of several targets and subsequently to obtain average resistive force of target points during impact. The velocities of the projectile (M2AP armor piercing bullets) are recorded in all the experiments, and they range from 915 to 975m/s. Postmortem analyses, which include through thickness sectioning, are performed oil each sandwich structure. The results show that armor panels with 3D woven backing have a higher ballistic efficiency than the 2D baseline panels, strike face damage mechanics are predominantly axisymmetric about the impact point and the panels with 3D backing had controlled delamination and fewer complete penetrations.