Jianwei Ren

Sandwich construction having hybrid core component with aramid composite encasement is proposed, whose ballistic behavior under flat projectile penetration is investigated through detailed 3D computations validated by experimental results. The ballistic response process of such a retrofitted sandwich, including progressive damage evolution, ballistic limit, and energy absorption, is characterized quantitatively or qualitatively. The effects of key aspects, such as interfacial properties and material constants of composite encasement and combination of both, are elucidated. An index quantifying the ballistic resistance of the target is proposed to evaluate the efficiency of improvement achieved by the composite encasement, compared with competitive structures. It is demonstrated that the presence of composite encasement endows an enhanced 33% ballistic limit and an increased 22% energy absorption compared to its counterpart, only accompanied with a 9 % increased mass. Such improvement in the penetration-resisting property is directly influenced by the interfacial property and material constant of the composite fabric, the former affecting in a nonlinear law and the latter in a positive relationship. Under a dual-parameter condition, the presence of composite encasement triggers a competitive damage pattern between its interfacial debonding and material failure, which exhibits a synergistically reinforced mechanical performance on the ballistic resistance of sandwich target, while maintaining an acceptable lightweight advantage. This research has broad implications for the design of lightweight engineering systems that integrate multiple service requirements.