Three-Dimensional Finite Element Analysis of Pipe Flange Connections : Effects of Solid-Metal Flat Gasket

Abstract

Almost all of the latest accidents of pipe flange connection are due to a leakage from gasket bearing surface. Important factors for the leakage problem are considered to be contact pressure distribution and the magnitude of contact area at the gasket bearing surface in service. The previous studies are not necessarily sufficient because of some restrictions involved in numerical analyses. In this study, therefore, the mechanical behaviors of pipe flange connection are evaluated in more detail using FEM as a three-dimensional elastic contact problem. The changes in contact pressure distribution at the gasket bearing surface and bolt axial stress are estimated with increasing inner pressure and bending moment. The analytical objects are pipe flanges specified in JIS B 2238 with solid-metal flat gaskets being inserted. The effects of material properties and thickness of the gasket are also studied. It has been clarified that the contact pressure distributions are different from those reported in the previous papers. The validity of the numerical method is ascertained by experiment.