Micromechanical analysis of off-axis loading of fiber reinforced composites with imperfect interface bonding

A micromechanical method based on generalized method of cells for investigating elastic and plastic response of composites subjected to off-axis loading is presented. Through implementing the formulas of interfacial displacement into average displacement continuity, the relationship between sub-cell strain rate and macro-strain rate is constructed in the condition of composites with wake interface bonding. On this basis, microstructure parameters, such as fiber cross-section shape, fiber volume fraction, are considered. Numerical results indicate that increasing fiber volume fraction will decrease the flow stress of composites in the condition of weak interfacial bonding. While the tendency is independent on fiber cross-section shape. Also, the effect of off-axis tensile strength tends to be weakened with the increase of off-axis angle in the condition of weak interfacial bonding. However, square fiber always provides more flow stress than circular fiber in both perfect interfacial binding and weak interfacial bonding.

► Numerical results indicate that increasing fiber volume fraction will decrease the flow stress of composites in the condition of weak interfacial bonding.
► The effect of off-axis tensile strength tends to be weakened with the increase of off-axis angle in the condition of weak interfacial bonding.
► Square fiber always provides more flow stress than circular fiber in both perfect interfacial binding and weak interfacial bonding.