Failure behavior analyses of piping system under dynamic seismic loading

Abstract

Some nuclear power plants in Japan experienced severe seismic ground motions that exceed their structural design specifications. Therefore, it is important to assess the margin of structural design against failure of piping systems under the severe seismic loading. The purpose of this study is to establish an analytical approach by which the failure behavior of piping systems can be simulated under severe dynamic seismic loading considering plastic effects. A series of dynamic-elastic-plastic analyses was performed focusing on a dynamic excitation test of a three dimensional piping system. The analytical results agree with the experimental data in terms of natural frequency, natural vibration mode, response accelerations, elbow opening-closing displacements, strain histories, failure position and low-cycle fatigue failure life.