Quasi-static and dynamic compressive fracture behavior of carbon/carbon composites

To understand the dynamic compressive fracture behavior of carbon/carbon composites, their compressive behavior was investigated at a strain rate of 500/s using a modified split Hopkinson pressure bar. Quasi-static compressive tests were conducted on a universal test machine and compared with those at high strain rate. Scanning electron microscopy was used to observe the compressive fracture surfaces. The results show that the compressive strength and stiffness are increased at high strain rate. Fiber failure under quasi-static compressive loading is characterized by fiber bundle debonding, breakage and pull-out, while the fiber failure under dynamic compressive loading is characterized by multiple splitting without extensive debonding.