複合材料 単繊維埋蔵横方向引張試験における初期損傷に及ぼす界面相特性の影響

Abstract

The embedded single fiber transverse tensile test has been proposed as a new experimental evaluation method on composite interfaces. The effect of surface treatment on microscopic damage, such as the interfacial debonding and matrix cracking around a fiber was investigated by in-situ SEM observation, when the transverse tensile load to the fiber longitudinal direction was applied to an embedded single fiber composite. The experimental result revealed that the surface treatment condition of fibers has an influence on the initiation and propagation of interfacial debonding and matrix cracking around a single fiber. In addition, the effect of interfacial properties on microscopic damage was investigated by a finite element analysis. The analysis was carried out by using a three layers model, which was modeled separately, fiber, matrix and interphase into the test specimen. The property for the interphase was assumed to be orthotropic, i.e. both tensile and shear moduli of the interphase are dealt independently to express the role of interphase for stress bearing and stress transfer separately. The effect of interphase properties was investigated by changing the tensile and shear moduli of the interphase. The reasonable elastic properties of the interphase were obtained by comparing the computational results with experimental ones. The Hoffman's failure criterion was used for judging of the damage in the interphase and the matrix. The validity of this analytical method is verified by comparing the analytical results with the experimental ones.