Plastic and Creep Analyses of the Superheater Header Tubeplate Using Linear Matching Method

In 2003 ASME PVP conference, a series of numerical procedures for integrity assessment based upon recently developed Linear Matching Method were presented [1]. A typical example of holed plate was used to verify these procedures for the evaluation of plastic and creep behaviours of complex geometry components based on linear solutions, which can be easily implemented into the commercial FE code ABAQUS through user subroutines. In this paper, a more complex 3D tubeplate in a typical AGR superheater header is analysed for the shakedown limit, reverse plasticity, ratchet limit and creep relaxation based on application of the Linear Matching Method. Both the perfectly plastic model and the cyclic hardening model are adopted for the evaluation of the plastic strain range. For the evaluation of accumulated creep strains, flow stresses and elastic follow-up factors with differing dwell times at the steady cyclic state, a creep-reverse plasticity model is adopted. The total inelastic strain range over the cycle at the steady cyclic state is calculated. By comparing these results with ABAQUS step-by-step inelastic analyses, the applicability of the methods is verified.