Phase-field modeling of crack growth under coupled creep-fatigue
Journal Article
·
· International Journal of Fatigue
- National Energy Technology Lab. (NETL), Albany, OR (United States)
Crack growth under coupled creep-fatigue strongly influences service life of metallic components operating at high temperatures. However, there lack numerical models that enable direct simulations of crack growth and plasticity development under coupled creep-fatigue. Here, in this study, a unified phase-field model is developed for simulating crack growth under fatigue, creep, and coupled creep-fatigue. This model is able to reproduce the Paris laws for both brittle and ductile materials in pure fatigue mode, which shows that the degradation rate due to cyclic stress in ductile materials is generally larger than that in brittle materials. Fatigue simulations with different yield strengths demonstrate that plasticity facilitates crack growth in typical ductile materials. High-throughput simulations are performed under coupled creep-fatigue conditions, with varying hold-stress levels and hold-time. By analyzing crack growth rate under different hold-time, a creep-fatigue interaction term is obtained. Simulation results demonstrate that the creep-fatigue interaction is caused by smaller stress gradient and enhanced degradation rate ahead of the crack tips under coupled creep-fatigue, compared to the situation of pure fatigue. This work reveals the origin of different Paris-law exponents in brittle and ductile materials and demonstrates how the interplay between creep and fatigue affects crack growth.
- Research Organization:
- National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Fossil Energy and Carbon Management (FECM)
- OSTI ID:
- 2513410
- Alternate ID(s):
- OSTI ID: 2440767
- Journal Information:
- International Journal of Fatigue, Journal Name: International Journal of Fatigue Journal Issue: 2024 Vol. 189; ISSN 0142-1123
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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