Experimentation and material modelling for cyclic plastic deformation behavior in Primary heat transport piping (PHT) materials

The present investigation is mainly aimed at examining cyclic plastic deformation response of primary heat transport piping material (SA333 C-Mn steel and 304LN stainless steel) of nuclear power plant and finite element modeling to predict cyclic plastic deformation behavior. Major conclusions from the work are listed below:
(1) Cyclic hardening/softening is not only dependent on material but also on the loading condition and loading history. Stress amplitude alternation in pure LCF
strongly depends on applied strain amplitude.

(2) True stress controlled ratcheting test procedure is scientifically correct way to evaluate material’s ratcheting response. During engineering stress controlled ratcheting experiment, true mean stress and stress amplitude increases to noticeable values, though engineering mean stress and stress amplitude maintained constant values. Due to reaching high true maximum stress in engineering stress controlled ratcheting test, specimens are failed by necking rather than crack propagation.