A fracture mechanics approach to the single fiber pull-out problem as applied to the evaluation of the adhesion strength between the fiber and the matrix

—A fracture mechanics approach to the problem of single fiber pull-out is formulated in terms of the critical energy release rate. The solution is more general than that of Outwater and Murphy [1] since the matrix compressive and shear rigidities are more realistic and stress distribution is taken into consideration. The model also takes into account frictional forces between the filament and the matrix along the debonded surface. The shear-lag method is used for stress analysis. A relationship between the filament pull-out force, the critical value of the energy release rate and the position of the tip of the cylindrical crack is established. Numerical examples show the effects of fiber and matrix rigidities and diameters on the apparent average debonding stress predicted by the model. The results of a computer study on the relationship between the pull-out force and the notch size are presented along with the analysis of the model sensitivity to different parameters.