Observing Through-Thickness Damage Timeline in Thick-Section Monolithic Composites under Soft Impact Load

The well-known weight saving capacities of composite materials have led to an increased interest in fiber-reinforced plastics as protective solutions for light armoured vehicles against blast threats. When subjected to such threats, materials undergo dynamic loading resulting in high strain rate levels. The majority of intra-laminar material properties such as stiffnesses and strengths are known to increase under dynamic loading. However, the characterization of interlaminar properties in terms of strength and toughness under dynamic conditions is still an open field in research. This paper presents an experimental setup capable of generating interface delaminations under high speed loading and while observing the damage timeline generated in through the thickness of the specimen in real-time. The use of High-Speed photography and Digital Image Correlation allows the experimentalist to measure the displacement field of the specimen, the through-thickness strain field, the onset and the propagation of delamination. Such measurements can then be coupled with explicit FE simulations to determine inversely the dynamic properties of the interfaces. Finally, the experimental results for 21 mm thick E-Glass woven laminates with a polyester resin are presented.