Detailed analysis of three elbow-pipe assemblies for typical load cases

In order to understand the mechanical properties of some kinds of elbow-pipe assemblies, which will be used for the piping systems of fast breeder reactors, the detailed elastic analyses are performed for typical three loading conditions. Many analytical works concerning the structural behavior of elbows have been made on the assumption that any planar section taken around the arc of the elbow deforms identically. However, for general elbow-pipe assemblies, this assumption is not valid at sections where the elbow is attached to other pipes or elbows, and then more accurate but expensive finite element techniques are required to include end-effects. It appears, therefore, that there have been not so many analytical studies including end-effects on the elbow-pipe assemblies such as U-bends. In this paper, we perform the detailed elastic analyses for a series of elbow-pipe assemblies under the basic loading conditions including end-effects by use of the recently developed special elbow elements of the FINAS (FBR Inelastic Structural Analysis System) finite element analysis system, and then discuss the design margins of the existing simplified methods. (orig.)