Experimental investigations on the in-plane dynamic compressive behavior and upper limit of constant strain rate for 2D twill weave carbon fiber reinforced composite

The in-plane dynamic compressive behavior of a 2D twill weave carbon fiber reinforced composite was investigated using the split Hopkinson pressure bar (SHPB) apparatus. Constant strain rate loading was achieved with the adoption of pulse shapers within the experiments. A non-dimensional parameter was adopted to verify the stress equilibrium state of the specimens, which ensured the effectiveness of the experimental results. The upper limit of constant strain rate for the composite, which determines the achievable range of constant strain rate, was analytically estimated and verified by the experimental results. On this basis, the dynamic compressive behavior of the composite was investigated within the strain rate range of 193/s-846/s. The stress-strain curves were obtained under the studied strain rates, an empirical equation for the strengths under different strain rates was summarized. Based on the experimental results, a viscoelastic constitutive model was adopted to characterize the dynamic stress-strain response. Finally, the deformation process of the specimens recorded through high speed photography was discussed.