On the Validity and Limits of the Gasket Effective Width Concept

Abstract

In the current ASME code procedure for the design of the gasketed bolted joints, the concept of the effective width is introduced to take into account the effect of the non-uniform gasket contact stress distribution. The code fixes a threshold value of the gasket width above which an adjustment of the gasket contact width is introduced. The validity of this threshold has never been verified. Under the normal operating conditions of flanges used with flat gaskets, the definition of this threshold is independent of the bolt load, the average gasket stress, the internal pressure and the flexibility of the joint. In this paper a study on the new limits of the concept of the effective gasket width is conducted. A new approach for the calculation of the effective gasket width, based on the results of an experimental investigation and undertaken in parallel to a numerical study, is presented. This approach takes into account the non-uniform distribution of the gasket stress, the flexibility of the flanges, the mechanical behavior and the sealing performance of the assembly.