Penetration characteristics of woven composite laminates impacted by hemispherical-nosed projectiles at different angles

The woven composite laminates with 2 mm in thickness were impacted by the hemispherical-nosed projectiles launched using a one-stage gas gun, and the impact angles were 0°, 30° and 45°. The process of projectiles impacting targets was recorded by a high-speed camera and the velocities of the projectiles were obtained. The experimental data was processed by the fitting formula to obtain the ballistic limit velocities at each impact angle and the results were compared with the theoretical model. The influence of the impact angles on the ballistic limits, energy absorption efficiency(EAE) and failure modes of the targets was analyzed. The results show that the ballistic limit of 45° oblique impact is the highest, then is normal impact and 30° impact is lowest. At the same impact energy, the energy absorption efficiency of 45° oblique impact is the highest, the EAE of 30° impact is more than normal impact at lower impact energy(<80 J), however, the EAE of normal impact is higher at higher energy(>80 J). The front surface of the targets is formed into circular indentation due to shear failure and the back is diamond bulge due to tensile fiber failure when impact normally. The targets are formed an ellipse reaming and their area increase with the increase of the impact velocity when oblique impact.