Life design method of high-temperature equipment based on dual-scale damage theory

The contradiction between the long-term safe operation of high-temperature structures and harsh service environment is becoming increasingly prominent. Creep-fatigue interaction damage has become increasingly prominent, leading to high failure rates of high-temperature components. In addition, the urgent demand for deep peak shaving in power generation units under carbon neutrality targets means that the critical high-temperature components face a lack of accurate life assessment methods. Traditional life design approaches based on single-scale or single-parameter are insufficient to simultaneously account for multi-axial stress effects and microstructural evolution in high-temperature structures, especially for the structures with inhomogeneous microstructures. In this paper, dual-scale modeling approach based on macro-continuum mechanics and micro-crystal plasticity is systematically introduced. Taking hole structure as an example, a life prediction method based on the dual-scale damage theory is presented. To facilitate the engineering application of the dual-scale theoretical framework, a creep-fatigue life prediction software considering surface strengthening effects is developed, enabling rapid damage assessment and life prediction for surface strengthening structures.