Estimation of Fracture Toughness of Fiber/Matrix Interface

Abstract

To estimate the level of interfacial adhesion between the fiber and polymer-matrix in fiber/matrix composites, interfacial fracture toughness was derived based on an energy balance scheme. A break gap occurring at the initial interface debond during fragmentation test was taken into account. The external work and work done against friction slip at debonded interface were included in energy balance scheme. The interfacial fracture toughness obtained is a function of fiber and matrix material properties and critical debond strain which is the external strain applied on the specimen to initiate interfacial debonding. The break gap calculated increases with increasing applied load and decreasing friction coefficient. The proportion of each energy terms in energy balance equation was calculated. Comparison between the predicted interfacial fracture toughness and that numerical result was done.