FEM Stress Analysis and Sealing Performance in Pipe Flange Connections With Gaskets Subjected to Internal Pressure and External Bending Moment

Abstract

This paper deals with the characteristics of a pipe flange connection with a compressed asbestos sheet gasket (JIS) subjected to an internal pressure and a bending moment. The contact gasket stress distributions at the interfaces between pipe flanges and a gasket are calculated by the elasto-plastic finite element method taking account a hysteresis and a non-linearity in the stress-strain curve of the compressed asbestos sheet gasket. In addition, measurements of a change in axial bolt force and leakage test were conducted using an actual pipe flange connection with the gasket subjected to the internal pressure and the bending moment. The new gasket constants are calculated by using the results of the leakage test and the calculated average contact gasket stress. The values of the new gasket constants obtained by the present study are in a fairly good agreement with those from ROTT (PVRC). It is found that the value of the tightness parameter is increased as the bending moment is increased. This is because the average contact gasket stress under the bending moment is increased, while it is decreased under the internal pressure.