The consideration of stress dependence in development of creep damage constitutive equations

Creep damage is a serious problem for power generation and high temperature industries.The life span for power generation installation is designed for long-term operation, say over 30 years. Thus the operational condition imposed on the majority of the components will be of lower stress level and the material and components behavior and its integrity under lower stress will be different from that under higher stress, resulting in the well-known stress breakdown. This paper will focus on the review of the stress level dependence of creep deformation and the damage mechanisms; the interpretation of cavity nucleation and growth in terms of damage evolution and rupture; the proposal of new creep damage kinetics and rupture criterion; and the framework for developing such creep damage constitutive equations.