Finite Element Analysis and In-situ Observation of Growth of Matrix Crack and Interfacial Debonding in Model FRP

Abstract

Single notched model composites, which consisted of boron fibers and the transparent epoxy resin, were used to observe the microscopic fracture process of unidirectional fiber-reinforced plastics during tensile testing. Tests were carried out under static loading. The in-situ observation revealed the typical fracture process as follows : First, matrix crack initiated at the notch tip and the crack growth was arrested by the neighboring fiber. Then, the onset and growth of interfacial debonding was observed while the main matrix crack was stable. The matrix crack growth and the interfacial debonding were repeated alternatively followed by the final overall fracture of the model composites. The three dimensional finite element analysis was carried out based on the in-situ observation. The observed fracture process was well reproduced and the values of the interfacial fracture toughness were evaluated.