Low-velocity Impact Damage Detection of Woven Composites Based on Ultrasonic Infrared Thermography

Low-velocity impact damage of woven composites is mainly caused by internal delamination damage, which cannot be effectively detected by visual inspection; this seriously reduces the structural load-bearing capacity and threatens the safe use of the compiled composite components. In this study, ultrasonic infrared thermography was used to perform nondestructive testing of the low-velocity impact damage of woven composites, and five specimens were produced using impact energies of 10, 20, 30, 40, and 50 J. The temperature increase and space temperature curves of the ultrasonic excitation process were analyzed. By comparing different impact energy specimens, it was found that the damage under low-speed impact was mainly internal, and the larger the impact energy, the larger the damage area. Moreover, the damage was ductile. The damage area was identified quantitatively using a curve classification algorithm. It was found that the damage area of woven composites and the impact energy were linearly correlated.