任意方向き裂エネルギー密度の評価と混合モード破壊基準としての可能性に関する基礎的検討

概要

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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,ε_φ, in an arbitrary direction can be divided into the contributions of each mode (ε_φ=ε^I_φ+ε^<II>_φ+ε^<III> _φ;ε^I_φ,ε^<II> _φandε^<III> _φare 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,ε_φandε^I_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^I_ is a potential parameter for expressing elastic-plastic fracture criterion under a mixed mode.
一般社団法人日本機械学会の論文
1989-08-25