配管系の弾塑性解析手法の検討 (その２)
概要
This report proposes an elasto-plastic analysis method to be used for practical aseismic designing of nuclear piping system made of austenitic stainless steel. This elasto-plastic analysis method is based on the elasto-plastic analysis method which has been decided by JSME. By using this analysis method, the results of has been reproduced with sufficient accuracy for the strain range used as the intensity evaluation index of austenitic stainless steel piping. For the model 1 composed of an elbow, the maximum strain estimated by elasto-plastic analysis using the elasto-plastic characteristics of stainless steel material determined as proposed by the draft code case of JSME agreed well, but on the safe side, with the experiment. However, this is not the case for the model 2 composed of a tee: the maximum strain estimated using the same elasto-plastic characteristics was underestimated compared with the experiment. A possible cause of the underestimate that occurred in the model 2 is, according to the shape data of the tee, that the wall thickness of the tee is so large that its connection with the main and branch pipes has a large, step-like change in thickness, as opposed to the model that was designed without referencing the shape data. Although there is the subject of modeling of a tee, the elasto-plastic behavior of stainless steel piping can be grasped. It seems that this analysis technology is applicable also to the preservation after an earthquake since this elasto-plastic analysis method can grasp the elasto-plastic behavior of austenitic stainless steel piping analytically.
