Energy Release Rate Based Fiber/Matrix Debond Growth in Fatigue. Part II: Debond Growth Analysis Using Paris Law

The strain energy release rate related to debond crack growth along the fiber/matrix interface in a unidirectional composite with a broken and partially debonded fiber is analyzed. The focus in this paper (Part II) in contrast to the self-similar crack growth analysis in Part I [1] is on growth of short debonds near the fiber break. Since self-similarity condition is not valid for interactive cracks, numerical FEM simulations were used to calculate magnification of previously described coefficients in the strain energy release rate expression. The findings from these studies are used in simulation of the debond growth in tension-tension fatigue using Paris law.