Inelastic Behavior of Finite Circular Cylindrical Shells

Abstract

In the design of elevated temperature components such as those encountered in Liquid Metal Fast Breeder Reactor (LMFBR) service, the designer/analyst is often faced with the task of having to assess structural adequacy of pressure vessel and piping components which experience high cyclic thermal stresses. Expensive and time consuming detailed inelastic analyses using finite element techniques are often necessary for such an assessment. Experience with the design of the LMFBR components has focused on an urgent need for simplified inelastic analysis methods which can aid the designer/analyst in scoping the design and minimize the number of parts requiring detailed inelastic analysis. Through its participation in the FFTF (Fast Flux Test Facility) and CRBRP (Clinch River Breeder Reactor Plant), Foster Wheeler Energy Corporation has developed a series of simplified analysis computer programs. The underlying philosophy in this work has been to make simplifying assumptions on the structural model but to solve the resulting boundary value problem as exactly as practicable so that approximations in the stress state or constitutive equations are not introduced. This paper is the third in a series [1, 11] by the authors dealing with the elastic-plastic-creep behavior of cylindrical structures. A rate formulation is presented for the elastic-plastic-creep analysis of finite circular cylindrical shells with various end conditions subjected to varying axisymmetric pressure loads, through-the-wall and along-the-length temperature gradients, and either axial loads or axial deformations. The solution procedure is based on direct integration and successive approximation and shown to be efficient in dealing with complicated loading histories. Applications of the present method of analysis are illustrated by numerical examples of elevated temperature design problem.