SINGULARITY ANALYSIS OF CYLINDRICAL INTERFACE END IN TRANSVERSELY ISOTROPIC BI-MATERIAL

Abstract

Micro-indentation, pullout, micro-debond and fragmentation test are widely used methods to measure the fiber-matrix interface shear strength (IFSS). In the stress singularity analysis of tests specimens, specimen materials are usually considered as isotropic, but in some cases, the properties of some kinds of fibers exhibit as transversely isotropic. Therefore, it is more reasonable and universal to adopt a transversely isotropic axisymmetric model in the singularity analysis for specimens of four kinds of tests. Based on this model, we first obtain the characteristic determinant, which is used to calculate the singularity index of interface end in specimens, following the procedure of coordinate transformation, asymptotic expansion and so on. Then, we calculate singularity indexes of the four test methods, and compare them with previous literatures where the fiber and the matrix are considered as isotropic. At last, we investigate the singularity in the Z-pinned laminate.