A strain-rate-dependent dynamic constitutive model of 2D-C/SiC composites

The layer-directional compressive mechanical properties of 2-demensional carbon-fiber-reinforced silicon carbide ceramic matrix composites (2D-C/SiC CMCs) were investigated at the strain rates of 10-4~ 2.8 103 s-1. The static experiments were done by using the electronic universal testing machine, and the dynamic experiments were done by using the SHPB system. The results show that the dynamic compressive stress-strain curve is non-linear. The failure strength and the elasticity modulus increase, and the failure strain decreases with the strain rate. The elastic modulus is linear to the logarithm of the strain rate. A new constitutive equation, in which the rate-dependent and damage-softening effects are considered, was proposed. This equation agrees well with the experimental results.