A Numerical Analysis of the Fatigue Strength of Ω-Bellows : 2nd Report, On the Thickness Effect and the Case of the Tensile Loading

Abstract

In the primary piping systems of nuclear power plants, many valves with bellows in their seal systems are used in order to prevent the leakage of high-pressurized and high-radioactive coolant. The Ω-bellows for high-pressure valves hold rings in them in order to heighten their compressive stiffness and reduce their stresses. The contact and frictional effects between the bellows and the rings prevent their stress analyses. In this paper, we analyzed the stresses in Ω-bellows using the finite element program applicable to contact problems, and then estimated the fatigue strength for 4 types of loading histories. The effect of the thickness of the bellows was investigated in two compressive types of loading. The reponses of two tensile types of loading were compared with the above results.