New approach to evaluation of fiber/matrix interface

A double cleavage drilled compression (DCDC) specimen has been analyzed by the boundary element method (BEM). At the same time, the DCDC specimen of FRP composites was proposed and used to evaluate the interfacial behavior and fracture energy in CFRP model composites. As a result, it was confirmed that the DCDC specimen had a mode I stress distribution for the hole offsetting displacement of b equals 0, which was of a symmetrical hole, while it had the mixed- mode stress distribution for b does not equal 0. The approach of calculating the interfacial fracture energy was established by using both of experimental results and analysis. Furthermore, the bridging fiber DCDC specimen was proposed and the effect of bridging fibers on the loading phase was made clear. It was shown that the DCDC test was a useful method to quantitatively evaluate the interfacial behavior of fiber/matrix in composites.