The linear matching method applied to the high temperature life integrity of structures. Part 2. Assessments beyond shakedown involving changing residual stress fields

Abstract

In an accompanying paper, the application of the linear matching method to the high temperature life assessment of structures was discussed and compared with assessment procedures, typical of those used in R5, for a range of cyclic problems within shakedown. These included shakedown and limit analyses, creep rupture analysis and the evaluation of rapid cycle creep deformation. In this paper, procedures based on the linear matching method are presented for a range of cyclic problems at higher stress ranges beyond shakedown involving changing residual stress fields. These include the evaluation of the plastic strain amplitude, ratchet limit and accumulated creep strains during high temperature dwell periods. The results are compared with calculation methods typical of the R5 methodologies. As in the accompanying paper, a 3D holed plate subjected to cyclic thermal load and constant mechanical load is assessed in detail as a typical example. The results demonstrate the flexibility of the linear matching method compared with current typical applications of high temperature assessment procedures.