Dynamic compressive behavior of four-step three-dimensional braided composites along three directions

Abstract

The dynamic compressive responses of the three-dimensional braided composites (3DBCs) were investigated using a split Hopkinson pressure bar (SHPB) apparatus. The strain rates of approximately 700–1900 s−1 were employed to analyses the responses in the longitudinal, transverse, and through-thickness direction. The corresponding quasi-static compressive tests were conducted on the universal testing machine. A high-speed camera was employed to record the progressive damage procedure for 3DBCs during dynamic events. The results indicated that the failure stress and compressive stiffness increased with respect to the increase of the strain rate, while the failure strain decreased with the increase of the corresponding strain rate under the dynamic loading conditions. Among the three directions, the highest failure stress and compressive stiffness were achieved along the longitudinal direction for the 3DBCs, followed by the ones obtained along the though-thickness direction, and the weakest values were obtained along the transverse direction. A meso‑scale finite element model (MSFEM) was developed to characterize the compressive behaviors. The numerical and experimental results correlated closely at the strain rate of 1847 s−1 along the longitudinal direction.