Fatigue Strength of Expansion Joints of Pressure Vessels

Abstract

The fatigue strength of expansion joints of pressure vessels under the axial load is studied. The fatigue tests in the elastic and plastic ranges are carried out by the fatigue testing machine designed for this purpose and the experimental data are treated by the Mises equivalent stress calculated from an elastic shell theory. The results are compared with the fatigue strength of test pieces made of the same material as the expansion joints and the method for prediction of fatigue life of expansion joints is discussed. The formula for estimation of life of 18-8 stainless steel expansion joints is proposed and compared with Kellogg's which is commonly used nowadays.