Linear and Non-Linear Analyses of Pressure Pipe Elbows

Abstract

The introduction of pressure piping increasingly requires the use of efficient materials which must withstand both high hydrostatic pressures, high mechanical loads and high thermal gradients. At nuclear power plants, piping systems are subjected to high pressures (up to 60 MPa). The occurrence of cracks and their possible spread is one of the serious risks in the industry. For this reason, elbows are considered critical components of a piping system. Therefore, in order to design and/or qualify a pipe structurally, it is useful to have a reliable evaluation of their structural behavior under different combined loads. The objective of this study is to determine analytical functions for the evaluation of the J integral as a function of crack size, elbow size, and the nature and intensity of loading. This assessment is derived from the numerical results obtained by the WARP3D calculation code exploiting the finite element method (FEM).