The effect of creep damage formulation on crack tip fields, creep stress intensity factor and crack growth assessments

Fields of stress, strain rate and process zone of a mode I creep crack growth are analyzed by employing damage evolution equations. Damage models for fracture of process zone represented by stress based formulation. Two expressions are presented to describe the stress-sensitive nature of multiaxial rupture behavior. Both damage free and defective creeping solids have been studied. The variation of creep stress and the crack-tip governing parameter in the form of creep In-integral with time and the evolution of creep damage were analyzed by using the FE-model. The effect of the introduced creep stress intensity factor as a function of creep time through the continuum damage mechanics of the creep crack growth are discussed in detail.