Fracture Criterion of a Mixed-Mode Crack (3rd Report, A Study on Evaluation of Fracture Paramenter CED in an Arbitrary Direction by Finite Element Method)

In the series of papers, the authors proposed the fracture criteria for mode I (opening type) fracture and mode II (shear type) fracture in a mixed-mode crack based on the CED (crack energy density) in an arbitarry direction, ε_φ, and the applicability of these criteria to mixed-mode crack has been investigated through the fracture experiments of specimens with an inclined crack under tensile/shear type loading. In this paper, the evaluation method of ε_φ by finite element method is studied. Elastic-plastic finite element analyses are carried out for the above mentioned fracture experiments and ε_φ and its contribution of each mode are evaluated by path-independent integrals and the method based on load-displacement curves. Based on the results, we examine the fundamental properties in the evaluation of ε_φ and so on in elastic case and, simultaniously, develop a practical method to evaluate ε_φ and so on in elastic-plastic case which makes the application of the fractrure criteria to the fracture of a mixed-mode crack realistic and easy.