抄録
Mechanical properties of fiber composites are dominated by the properties of fiber, matrix and the fiber/matrix interface. Especially the transverse and off-axis behaviors of unidirectional fiber composites are affected by the state of the interfacial adhesion. The effects of interfacial debonding (cavity formation) on the transverse elastic moduli of unidirectional fiber composites have been analyzed by Takahashi et al. In this paper, a mathematical model is developed to predict the intermediate state between the perfect adhesion and the cavity formation. It is assumed that the fiber and matrix can freely slip each other but they are not separated at the interface, i.e., the normal stress and displacement in the radial direction are continuous through the interface although the shear stress between the fiber and matrix vanishes. The expressions for the displacement and stress components are formulated using the theory of plane strain elasticity. Numerical examples are presented for a boron/aluminum composite subjected to the transverse uniaxial tension and the effects of the interfacial slippage on the transverse stress distribution are investigated analytically. The analytical model developed here constitutes the theoretical basis for the prediction of the initiation and growth of the in-terfacial crack and the accompanying stiffness degradation of the composite.
