Reference solution and proportional method to calculate intensity of singular stress field (ISSF) at the interface corner where reinforced fiber enters resin matrix

To evaluate fiber/matrix bonding properties, the average shear stress is generally used as the interface strength without considering the intensity of singular stress field (ISSF) at the interface ends. In this paper, therefore, how to calculate the ISSF is described in detail at the fiber entry point of the single-fiber under pull-out test. Recent studies showed the ISSF method is quite useful for controlling the debonding strength. As a reference solution, the ISSFs at the fiber entry point are tabulated and illustrated under arbitrary material combination for the specific geometry. By applying the proportional method with this reference solution, the ISSF can be calculated for other geometries conveniently. As an example, the ISSFs of Glass fiber and Carbon fibers are shown to be obtained from the reference solution within 1 percent error. Utilizing those results, the difference between the pull-out test and the micro-bond test is discussed by varying the reinforced fiber properties.