Creep-Fatigue Terminology
Concise reference for creep-fatigue interaction terms — hold time, dwell, interaction diagram, damage fraction, TMF, in-phase, out-of-phase.
Key terms
- Creep-fatigue: combined damage from cyclic fatigue and sustained-load creep
- Hold time (dwell): period of sustained load within a fatigue cycle
- Interaction diagram: plot of creep damage fraction vs fatigue damage fraction
- Damage fraction: creep D_c = sum(t_i/t_ri), fatigue D_f = sum(n_i/N_i)
- Linear sum: D_c + D_f < 1 (simplest interaction criterion)
- TMF: thermomechanical fatigue — simultaneous thermal and mechanical cycling
- In-phase TMF: temperature and stress peak together
- Out-of-phase TMF: temperature peaks when stress is minimum (or vice versa)
- Thermal fatigue: cyclic thermal stress without mechanical cycling
- Strain range: total mechanical strain range per cycle (fatigue driver)