EXPERIMENTAL STUDY ON DYNAMIC COMPRESSIVE PROPERTIES OF 3D FOUR DIRECTIONAL BRIADED COMPOSITES

The mechanical properties of the 3D four-directional braided composites were investigated by using split Hopkinson pressure bar (SHPB) in transverse direction. The stress-strain curves for the composites along transverse direction were obtained at strain rates ranging from 900/s to 1500/s, and compared with the quasi-static compression test results. The effect of strain rate on compressive strength and modulus was discussed. Based on the SHPB hypothesis as well as pulse shaping technique, the specimen was made in equivalent stress and constant strain rate over the course of experiment. The results show that the compressive strength and modulus are sensitive to strain rate. The dynamic strength and modulus of the composites exhibit considerable increase as compared with the quasi-static values. The effect of strain rate on the failure mode was also analyzed.