Flexural damage and failure behavior of glass fiber epoxy composites repaired by patch embedded with ZnO whiskers

摘要

Three-point bending tests are employed to research the damage behavior of glass fiber epoxy composites repaired by patch embedded with ZnO whiskers. In particular, the role of ZnO whiskers is discussed in detail. In the whole process, acoustic emission and digital image correlation are performed to monitor the damage behaviors in real time. The results indicate that matrix cracking and delamination damage are the main failure mode between the patch and the motherboard during the process of fracture failure. Correspondingly, the acoustic emission signals with high relative energy and high amplitude are generated. Besides, the cumulative hits increase dramatically. Therefore, the stress concentration at the interface of composites can be analyzed indirectly by the change of acoustic emission signals. ZnO whiskers and resin matrix have a good bonding property, the failure load and matrix strength of the repaired specimens increase significantly. Moreover, ZnO whiskers collaborate with the resin matrix to resist some external forces, increasing the stiffness and the resistance ability to deformation of the repaired composite specimens.