Low-velocity impact and compression after impact behavior of 3D integrated woven spacer composites

Due to their superior overall properties, 3D integrated woven spacer composites overcome the weakness of traditional sandwich composites under low-velocity impact (LVI). The dynamic response of carbon fiber 3D integrated woven spacer composites under LVI and failure behavior under compression after impact (CAI) were experimentally investigated in this work. The impact damage patterns were analyzed using ultrasonic C-scan and micro-CT techniques at various energy, while digital image correlation (DIC) was used for CAI analysis. The results indicate that the impact damaged areas of X-type specimens is 365.1 mm2 under the impact energy of 7 J, while that of Y-type specimens is 371.4 mm2. The maximal absorbed energy is very close for two types of 3D integrated woven spacer composite specimens, which is about 6.99 J. The residual strength of X-type specimens decreases by 38.9% after the impact energy of 7 J, while that of Y-type specimens is reduced by 24.6%. The damage mechanism of the composites under LVI and CAI was obtained, which can provide some guidance for designing more suitable 3D integrated woven spacer composite structures in engineering practice.