Numerical investigation of energy absorption mechanisms in unidirectional composites subjected to dynamic loading events

This work serves as an initial investigation, which is purely numerical, of three energy absorption mechanisms of severe dynamic loading events using a finite element model of a cross-ply unidirectional (UD) composite laminate. In this study, the inelastic energy absorption mechanisms associated with damage at the interfacial and constituent levels were numerically characterized through three admissible failure modes: fiber breakage, matrix shearing, and fiber/matrix debonding (delamination) (i.e., cohesive failure). The UD composite was constructed of ultrahigh molecular weight polyethylene (UHMWPE) fibers separately reinforced with a polymer matrix material. The energy absorption capacities of these damage mechanisms were contrasted for three different dynamic loading cases including blast, shock, and ballistic impact at three different energy levels. Energy loss due to cohesive failure was observed in all three loading cases and energy levels. Furthermore, energy loss due to matrix failure was observed at all energy levels for the blast case, but only for the highest energy level in the shock and ballistics. There was energy loss due to fiber failure in the blast and in the highest energy ballistics impact case. However, there was not any fiber damage in the shock case.