EFFECTS OF RESIDUAL-STRESS AND INTERFACIAL FRICTIONAL SHEAR-STRESS ONINTERFACIAL DEBONDING AT NOTCH-TIP IN 2-DIMENSIONAL UNIDIRECTIONAL COMPOSITE

A calculation method based on the shear lag approach was presented to gel an approximate estimate of influences of residual stresses and fri ctional shear stress at the debonded interface on the interfacial debo nding behavior at the notch-tip along fiber direction in two-dimension al unidirectional double-edge-notched composites. With this method, th e energy release rate for initiation and growth of debonding as a func tion of composite stress were calculated for some examples. The calcul ation results showed in outline how much the tensile and compressive r esidual stresses in the matrix and fiber along fiber direction, respec tively, act to hasten the initiation and growth of the debonding when the final cut element in the notch is matrix, while they act to retard them when the final cut element is fiber, and how much the frictional shear stress at the debonded interface reduces the growth rate of the debonding.