Experimental investigation on dynamic compressive behaviors of carbon cloth/carbon composites

Dynamic compressive behaviors of carbon cloth /carbon composites were experimentally studied at the strain rates of 500, 1 500 s-1 by the split Hopkinson pressure bar with pulse shaper. Experimental results show that the pulse shaping technique ensures nearly constant strain-rate deformation experienced by specimens under dynamically equilibrated stresses so that accurate stress-strain curves at two high rates can be obtained. Compared with quasi-static compression, the dynamic compressive strength of carbon cloth/carbon composite has strong stain-rate sensitivity and it increases with strain rate. A phenomenological strain-rate-dependent material model of Cowper-Symonds power function was proposed to describe the stress-strain response of composites. The calculated results by the proposed model agree well with the experimental data at high and low strain rates.