The Evaluation of Crack Opening Areas for Through-Wall Cracks in the Vicinity of Pipe Branch Connections

Abstract

A number of papers have been presented at previous ASME PVP conferences, which have evaluated the crack opening areas (COA) and stress intensity factors (K), using elastic finite element analysis techniques, for through-wall cracks in a region where an attachment is welded to a plate. This was a simplified geometry aimed at representing a more complicated geometry of a pipe-branch connection. A number of analyses were considered and conclusions made on the estimation of COA and K using simple handbook solutions. More recently the analyses included the application of nonlinear geometry and the addition of crack face contact when applying bending loads. This paper is a continuation of these previous studies, assessing through-wall cracks in a more realistic pipe-branch connection geometry. The calculated COA and K values for the more complex geometry are compared to values from pipe models with no branch connections, in a similar manner to that applied in the previous work on the simplified plate geometry. Judgments are made on the conservatism, or otherwise, of the estimated COA and K for the more complex geometry solutions compared to the simple geometry solutions.