Analysis of cyclic creep and rupture. Part 2: calculation of cyclic reference stresses and ratcheting interaction diagrams

Part 1 gives the basis for the use of cyclic reference stresses for high temperature design and assessment. The methodology relies on elastic-plastic calculations for limit loads, ratcheting and shakedown. In this paper we use a commercial non-linear finite element code for these calculations. Two fairly complex and realistic geometries with cyclic loads are analysed, namely a pipe elbow and a traveling thermal shock in a pressurized pipe. The special case of start-up shut-down cycles is also discussed. Creep and rupture predictions may be made from the results. When reference stresses can be economically calculated, their use for high temperature design has the following advantages.