Effect of excessive compressive loading on crack growth behavior

Yamaguchi, Yoshihito ; Li, Y.* ; Sugino, Hideharu*; Katsuyama, Jinya  ; Onizawa, Kunio 

In recent years, Japanese nuclear power plants experienced multiple large earthquakes, such as Niigata-ken Chuetsu-Oki Earthquake in 2007 and the Tohoku District - off the Pacific Ocean Earthquake in 2011. Therefore, it is very important to assess the structural integrity of reactor piping under such a large earthquake when a crack exists in the piping. In this study, an effect of excessive compressive loading on the crack growth behavior of piping materials has been evaluated through cracked plate testing. It was observed that excessive compressive loading had an acceleration effect on crack growth rate. The evaluation method using J-integral to evaluate the crack growth behavior under the condition beyond small-scale yielding has been proposed for the acceleration effect of excessive compressive loading on crack growth rate. It was indicated that the acceleration effect by excessive compressive loading simulating a large earthquake could be evaluated using the proposed method.