Bridging tensor with an imperfect interface.

Bridging tensor is fundamental to the Bridging Model for prediction of thermomechanical and strength behaviors of a fiber reinforced composite based on constituent fiber and matrix properties. This paper focuses on derivation of the bridging tensors with an imperfect fiber–matrix interface. Using a three-phase coaxial cylinder assemblage (CCA) model, the stress fields in all of the three materials in the assemblage when subjected to six kinds of loading conditions are obtained by means of rigorous elasticity theory. The stresses are then averaged with respect to the corresponding phase volumes. By imposing that the averaged stress components in each phase be correlated with those in an adjacent phase through a bridging tensor and solving the resulting simultaneous linear algebraic equations, the bridging tensor elements are determined. Comparison of the thus obtained effective off-axis moduli with experiments for a SCS-6/Ti unidirectional (UD) composite is made to show the efficiency of the three-phase bridging tensors. Effect of interphases on the effective elastic properties and stress ratios of the composite with different coatings is investigated. [ABSTRACT FROM AUTHOR]