An improved analytical model for inversely determining multiple interfacial parameters from single fiber micro-Raman and fragmentation tests

Inverse identification of fiber/matrix interfacial properties from single fiber micro-Raman or fragmentation test requires an accurate model prediction of stress transfer near a fiber break. The existing models adopt very simplified interfacial constitutive law, and hence the three key interfacial parameters, i.e. interfacial shear strength, fracture energy and frictional stress, cannot be determined simultaneously from the single fiber composite test. In this work we develop an analytical model for stress transfer analysis near a fiber break, in which the three important interfacial parameters are all introduced. The present model is well validated by finite element simulations through comprehensive comparisons of stress profiles in fiber and fiber/matrix interface. As demonstrated by several examples, our model shows a good ability to inversely identify interfacial shear strength, fracture energy and frictional stress simultaneously for both single fiber micro-Raman and fragmentation tests. This unified model is also expected to minimize the error between the interfacial parameters identified by different test methods.