Transient elastic-plastic-creep crack-tip stress fields under load-controlled loading

This paper presents transient and steady-state elastic-plastic-creep crack-tip stress fields under load-controlled loading conditions for a wide range of combinations of power-law plastic and creep materials. The crack-tip stress fields are characterized in terms of 2 parameters to accommodate the crack-tip constraint effect; the C(t)- (or C*-) integral and the β_Q parameter (the Q-parameter normalized with respect to the proximity parameter to plastic collapse). For practical application, the crack-tip stress fields are re-formulated explicitly in terms of time and crack-tip stress fields for elastic-plastic and steady-state creep conditions. Comparison with detailed FE results for plane strain tension and bend specimens shows that this formulation of the crack-tip stress fields agrees well with finite element results.