Numerical Simulation of Energy Absorption Performance and Failure Mechanism of CFRP Composites under Fragment Impact after Explosion

The application of carbon fiber reinforced polymer (CFRP) composite in protective equipment is restricted by its complex penetration behavior and unclear failure mechanism under fragment impact. To overcome the difficulty and high cost of monitoring the penetration process information through experiments, a finite element analysis (FEA) model of CFRP composite under fragment impact is constructed in this study. In this model, a strain-based three-dimensional Hashin failure criterion is adopted, and the rate-dependent relationship of strength is introduced. The effectiveness of the FEA model is verified by comparison with experimental results. The simulation results show significant difference in both initial velocities and impact inclination angles under different TNT equivalents and distances from the explosion point. The inclination angles of fragments with the target plate on y-z and x-z planes are defined as α and β. When β=0°, CFRP composites exhibit pronounced impact velocity sensitivity in the velocity range of 195−392 m/s. The energy absorption capability and impact velocity sensitivity of specimens with different inclination angles β are significantly different. However, the energy absorption capability and impact velocity sensitivity of specimens with different inclination angles α do not show significant differences. When α=0°, the impact velocity sensitivity of CFRP composites in the impact velocity range of 195−392 m/s gradually declines with the increase of inclination angle β. Visualization of the penetration process and failure area indicates that the contact area and time and deformation degree are the crucial reasons for the differences in energy absorption capability and impact velocity sensitivity observed in CFRP composites.