Energy absorption behaviors of 3D braided composites under impact loadings with frequency domain analysis

This article presented the energy absorption behaviors and damage mechanisms of 3D braided composites under transverse impact and low‐velocity impact with frequency domain analysis method. The transverse impact tests were contracted by modified split Hopkinson pressure bar with the impact velocities of 13.6, 17.8, and 22.8 m/s. The low‐velocity impact tests were performed by Instron 9250 drop‐weight instrument with the impact velocities ranging from 1 to 6 m/s. The experimental results shown that the peak load, displacement to peak load, total energy absorption increased with the increase of impact velocity. The damage morphologies showed the failure mode of 3D braided composite. Increased with the impact velocity, the failure mode changed from resin crack to fiber breakage. The frequency domain analysis results showed that the amplitude of stress wave increased with the increase of impact velocity, but its corresponding frequency was irrelevant to impact velocity. The different amplitude regions corresponded to different failure mode. POLYM. COMPOS., 37:1620–1627, 2016. © 2014 Society of Plastics Engineers