BIAXIAL RATCHETING AND CYCLIC PLASTICITY FOR BREE-TYPE LOADING .1. FINITE-ELEMENT ANALYSIS

The Bree diagram has been incorporated in the ASME B&PV Code in the el evated temperature Code Case N47 as a design approach for limiting str ain accumulation in cylinders subjected to cyclic thermal loadings und er sustained primary stress. Since the Bree diagram is based upon unia xial-stress model, it is pertinent to examine the influence of biaxial stresses on strain growth and cyclic stress-strain hysteresis respons e. The results of inelastic analyses presented in this paper showed th at ratcheting and hysteresis behavior may also occur in the axial dire ction in addition to the hoop direction. Results of almost 100 load ca ses were presented to clarify the influence of biaxial membrane and th ermal bending stresses on the structural behavior. A design approach f or the assessment of this type of problem was suggested which utilizes these results.