On the integrity of piping systems containing axial and circumferential surface flaws

The present developments in the mechanics of fracture of pressure vessels and pipings are mainly in the non-linear plastic and dynamic domains. A linear analysis remains necessary for fatigue growth calculation and for possibly embrittled parts. In this paper the integrity analysis of pipes and piping components such as T-branches, reducers, flanges, elbows, etc. is discussed on the assumption that crack-like flaws are present. The methods used here were originally developed for nuclear applications. Due to its interest and continuous involvement in piping integrity research, the US NRC has recently initiated an international group research program called IPIRG on this topic. Similar activities in Germany are included in the research programs “Basic Safety/Exclusion of Failure of Components”.