1004 弾塑性破壊力学パラメータに基づく繰返し過大荷重による配管材のき裂進展評価法の提案(OS10-1 供用エネルギー機器の経年変化と健全性評価-欠陥評価-)

概要

論文の詳細を見る
The magnitude of Niigata-ken Chuetsu-Oki earthquake in 2007 was beyond the assumed one provided in seismic design. Therefore it becomes an important issue to evaluate the crack growth behaviors due to the cyclic overload like large earthquake. Fatigue crack growth is usually evaluated by Paris's law using the range of stress intensity factor (ΔK). However, ΔKis inappropriate in a loading condition beyond small scale yielding. In this study, the crack growth behaviors for piping materials were investigated based on an elastic-plastic fracture mechanics parameter, J-integral. It was indicated that the crack growth due to the cyclic overload beyond small scale yielding could be the sum of fatigue and ductile crack growth. The retardation effect of excessive loading on the crack growth was observed after the loading. The modified Wheeler model using J-integral has been proposed for the prediction of retardation effect Finally, an evaluation method for crack growth behaviors due to the cyclic overload was suggested.
一般社団法人日本機械学会の論文
2010-10-09