Study on Fracture mode Transition of Unidirectional CFRP by Using Homogenization. (2nd Report, Numerical Analysis).

Abstract

In the previous experiments of unidirectional CFRP subjected to tensile load in the fiber direction, the various fracture modes were observed, depending on the thickness ratio (t/T), the fiber volume fraction (Vf) and the testing temperature. With increasing the value of these factors, the fracture mode transferred from tensile mode to mixed mode and shear mode. On the other hand, in the analysis for fracture mode transition of CFRP by the conventional finite element method using the equivalent material constants, the results showed qualitative validity, although microscopic fracture such as the shear fracture at the interface or fiber rupture was not taken into account. In this study, the fracture propagation method is proposed for unidirectional CFRP using the homegenization method which can evaluate the micro and macroscopic response simultaneously. In the previous paper (Part. 1), the formulation of fracture propagation analysis method was introduced. In this paper, numerical analyses are conducted for the fracture mode transition of the unidirectional CFRP depending on t/T, Vf and testing temperature. The fracture mode transition can be simulated by the present analysis method and numerical analyses results agree with the experimental results.