拘束効果を考慮した極低サイクル疲労下におけるき裂進展条件クライテリオンの提案

（CTおよび両側貫通切欠き試験片による評価）

抄録

The strength evaluation of structures that requires high reliability, such as power generation facilities, is extremely important. It is necessary to ensure safety under extremely low cycle fatigue caused by earthquakes. However, a highly reliable evaluation method has not yet been developed because of variable fracture toughness due to the constraint effect with large deformation. The crack propagation criterion proposed in the previous study was confirmed validity under restrict condition. However, it is not considered constraint effect such as thickness and material properties. The objective of this study is confirmed whether the crack propagation criterion proposed in the previous study can apply changing of constraint effect. Furthermore, we propose the crack propagation criterion considered constraint effect under extremely low cycle fatigue.