A lifetime model for creep-fatigue interaction with applications to the creep resistant steel P92. (September 2021)

• Record Type: Journal Article
• Authors: Riedel, Hermann; Maier, Gerhard; Oesterlin, Heiner
• Is Part Of: International journal of fatigue. Volume 150(2021)
• Publication Date: 2021-09
• Subjects: Creep-fatigue in power plants -- Codes and standards -- Mechanism based model -- Creep-fatigue tests -- P92; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2021.106308
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: A creep-fatigue model based on fatigue microcracks and grain boundary creep damage. New creep-fatigue damage parameter DFC . The model is validated by tests on the steel P92. Better understanding of the creep-fatigue interaction diagram. Improvement of codes and standards. Abstract: Methods proposed by current codes and standards to deal with creep-fatigue problems are far from being satisfactory. For a better understanding, a model is developed based on grain boundary cavitation (representing creep damage) and microcrack growth (representing low-cycle fatigue damage). Creep-fatigue interactions occur by (1) contributions of creep deformation to fatigue crack growth, and (2) enhanced creep rates after load variations, as they occur, e.g., during start/stop cycles. Experiments on the steel P92 confirm the predicted lifetimes as a function of the stress-temperature loading history. A creep-fatigue damage parameter, DFC, is introduced to characterize the load cycle.