The Characteristics of Bolted Joints with Gaskets : Stress Analysis of a Metallic Flat Gasket Used for Raised Face in a Cover of Pressure Vessel

Abstract

Designing of bolted joints with gaskets mainly depends on experience and the sealing performance is not yet clarified by theoretical analyses. In this paper, discussion is made on the contact stresses of bolted joints in the case where a metallic gasket used for raised face is interposed between the cover and the base of a pressure vessel. The distribution of contact stresses in a metallic gasket is analyzed as a three-body contact problem using the three-dimensional theory of elasticity. Effect of the stiffness, the thickness and the position of gaskets on the distribution of contact stresses are revealed by numerical computations. Furthermore, the force ratio of bolted joints with gaskets, that is, the ratio of an increment of bolt axial force to an internal pressure, is analyzed. Experiments on the force ratio are carried out. Analytical results are in a fairly good agreement with experimental ones.