Fracture Behavior and Acoustic Emission of SFC

Abstract

The fracture behavior of SFC materials containing a single carbon fiber emedded in epoxy or nylon 6 matrix which were loaded in tension was examined by AE monitoring. It was confirmed that AE signals resulted from fiber breakage and the number of AE events was in a good agreement with the fiber fragments produced during the fracture process. The mean fragment length and interfacial shear strength were calculated by using the number of AE events, and they were comparable with those obtained from the fragment length distribution and the micromechanical model. The specimen thickness influenced the mean fragment length and the interfacial shear strength, but the tensile speed in the experimental conditions did not. It was shown that the interfacial shear strength for the SFC with epoxy matrix was higher than that with nylon 6 matrix in the same treatment of a fiber surface. The difference in fracture behavior between two SFC materials with epoxy or nylon 6 matrix was also observed by AE spectrum analysis.