き裂の応力・ひずみ場に及ぼす小規模クリープと硬化・回復の重畳効果に関する有限要素解析

抄録

The authors have pointed out previously that the modified J-integral, J', near a creep crack tip is extremely high under the small-scale-creep conditions. Also, the J'-values in the transient creep, in which hardening exceeds recovery, are much higher than those in the steady-state creep, where an equilibrium between hardening and recovery is attained. The interaction of these two effects may multiply the increase in the J'-values during the transient creep. This paper is concerned with finite element simulation of this combined effect. The Robinson's model was employed to account for the effect of hardening and recovery during creep. It was found that the small-scale-creep effect was predominantly responsible for the increase in the J'-values during the initial part of loading time. The behavior of J' was explained in terms of the sizes of the creep-dominated region and the steady-state creep region.