Strain rate-dependent compressive properties of C/C composites

To understand the strain rate sensitivity of compressive properties of carbon/carbon (C/C) composites, both the quasi-static and dynamic compressive tests of C/C composites were conducted using electronic universal testing machine and modified split Hopkinson pressure bar (MSHPB) with pulse shapers. The results indicated that the compressive strength and stiffness of the C/C composites were sensitive to the strain rate, and increased with the increase of strain rate. The samples failed by shearing under quasi-static loading, and by crushing under dynamic loading. The fiber failure was characteristic of extensive debonding within bundle and many small steps under quasi-static loads, where as, the fiber failure was characterized by fiber bundle multiple splitting with abrupt fracture surfaces under dynamic loads.