A Simple Method for Calculations of Steady-State Creep Rates in Nonconservative Plastic Deformation

A simple yet powerful method is developed to calculate steady-state creep rates in a nonvolume conservative plastic deformation that is linear in the applied stress. The method is applicable to complex stress distributions that exist in many nuclear reactor core components. Application of the method leads immediately to the steady-state creep rates for bending in plane stress and plane strain for a swelling rate that depends on position only through variation in the hydrostatic stress. The bending rate in plane strain can be significantly lower than the corresponding rate in plane stress. The method accommodates arbitrarily spatially varying stress-free swelling rates with only minor generalization. For example, the steady-state stress distribution induced by non-uniform swelling through a tube wall is obtained simply by application of standard formulas for thermal stresses in this geometry.