It has previously been shown that crack energy density can be defined in any direction at a crack tip without any restrictions on constitutive equations. The crack energy density, εφ, in an arbitrary direction can be divided into the contributions of each mode (εφ= εI φ+εII φ+εIII φ;εI φ,εII φand εIII φ are the contributions of modes I, II and III, respectively), which can be evaluated by path-independent integrals corresponding to each. These are defined for a completely sharp crack as the limits where the notch root radius ρ approaches zero in a notch model. Therefore, it is necessary to use a notch model with a sufficiently small value of ρ in evaluations of the quantities through FEM. In this paper, εφ and εI φ are evaluated by path-independent integrals through elastic-plastic finite element analyses varying the value of ρ, and we discuss which of ρ should be adopted in evaluations of them. Moreover, by applying these results to an experimental result of ductile fracture under a mixed mode, we show that εI φ is a potential parameter for expressing elastic-plastic fracture criterion under a mixed mode.
|ジャーナル||Transactions of the Japan Society of Mechanical Engineers Series A|
|出版ステータス||Published - 1989|
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