Assessment of Overlapped Internal and External Volumetric Flaws in p-M Method

Assessment of overlapped internal and external volumetric flaws is one of the most common problems relating to pressure vessels and piping components. Under the current Fitness for Service (FFS) rules, such as ASME, BS and so on, the procedures have not yet defined how to assess these flaws. In this paper, a new procedure for these volumetric flaws is proposed for assessing the flaws by the p-M (pressure-moment) diagram method, which is a simple assessment procedure. Numerous FEAs for a cylinder with overlapped internal and external flaws were conducted to verify the proposed procedure. There is good agreement among them.