Effect of Matrix Resin Characteristics on the Fracture Behavior for Plain-Woven Carbon Fiber Reinforced Plastics fabricated by Vacuum Assisted Resin Transfer Molding

Acoustic emission (AE) measurement has been used to investigate microscopic failures and damage progress in carbon fiber reinforced plastics (CFRP). In this work, AE measurements were conducted on plain-woven CFRPs fabricated by vacuum-assisted resin transfer molding process and neat epoxy resins during tensile tests to evaluate the failure modes. Four types of epoxy resins were used as matrix resins to investigate the effects of matrix resin characteristics on the microscopic damage behavior and the mechanical properties of CFRP. As a result, the mechanical properties of on-axis CFRP were comparable regardless of matrix resins. On the other hand, in the case of off-axis CFRP, such as 45° direction, the tensile strength was remarkably lower with a brittle matrix resin. From the AE measurement results, the number of cumulative hits for CFRP was much larger than that for neat resins due to the occurrence of fiber/matrix interfacial cracks. Also, AE waves for CFRP had a longer duration than that for neat resin, and the relationship between the degree of duration and fracture mode was clarified.