EXAMPLE CLASS B PRESSURE VESSEL DESIGN ANALYSIS USING PROPOSED CODE CASE ELASTIC PERFECTLY PLASTIC RULES

A proposed code case for ASME BPVC Section III, Division 5, Class B Components is being developed to provide elastic perfectly plastic (EPP) rules that can be used as an alternative to the elastic rules contained in Subsection HC, Subpart B. As part of the development of the code case, an example Class B pressure vessel with elevated temperature loading was used to exercise the rules. The example analysis provided insight on applicability of the proposed rules and allowed for further refinement of the code case. This paper documents the example Class B pressure vessel providing background on the development of the code case and providing insight into how to apply the rules. The selected example vessel geometry includes a cylindrical shell, top flat head, bottom torispherical head, and center inlet/outlet nozzles such that an axisymmetric model can be used to perform the EPP analyses. The vessel is supported from the top head using a thermally isolated support ring, which allows for free radial thermal expansion. Construction material for the vessel is selected as 316 stainless steel with appropriate weld filler material. Loading conditions are selected to exercise various aspects of design and service condition primary load limits, strain ratcheting limits, and creep-fatigue damage addressed in the proposed code case.