Mechanical behavior and failure mode of woven carbon/epoxy laminate composites under dynamic compressive loading

The compressive behavior of woven carbon/epoxy laminate composites is investigated under in-plane and out-of-plane loading. The Material Testing System (MTS) and the Split Hopkinson Pressure Bar (SHPB) are employed to test the quasi-static and high strain rate dynamic mechanical properties of the material, respectively. Dynamic compression properties are compared with those of static loading. It is observed that the failure strength varies with different fiber woven directions. The results indicate that the stress-strain curves, maximum compressive stress and strain all evolve as strain rate varies. The specimens are mainly damaged in shear failure mode under out-of plane loading and the shear failure mode is independent of loading states and strain rates (500-1000/s). Comparatively, the different failure mechanisms of the material between quasi-static and dynamic in-plane loading at strain rates ranging from 50 to 400/s are obtained and studied. Delamination is only found at high strain rates under in-plane dynamical loading while shear deformation and delamination are both found under in-plane quasi-static loading. Shear bands and deformation zones are also observed under in-plane quasi-static loading.