A physically motivated mechanistic MultiStage Fatigue (MSF) model was developed for variable loading and multiaxial loading cases for notched structures. The MSF model depicts the effects of microstructural features on fatigue damage evolution stages, i.e., incubation, small crack growth, and long crack growth, allowing the assessment of variations in fatigue behaviors associated with the random microstructural features and stochastic interference between fatigue damage and those microstructural features. Therefore, the MSF model is an example of a necessary fatigue model for a structural health prognosis system. In this paper, special functions/effects in notched structures related to prognosis-specific requirements for airframe structures were evaluated and added into the MSF model. The notch-root behavior was presented as a function of not only the local plasticity accumulation but also the damage at the microscale associated with cyclic loads. Meanwhile, overload effects to the microplasticity in the vicinity of intermetallic particles were incorporated into the incubation model. Thus, the variable loads associated with generic flight spectrum were reorganized based on the transient material behavior at notch root. Finally, the MSF model was validated to predict damage and fatigue life of a wrought aerospace-graded Al alloy in experiments under various spectrums and notch root stress concentrations.
Physics-based multistage fatigue model for fatigue in notched structures
Physikalisches Mehrstufen-Ermüdungsmodell für das Ermüdungsverhalten in gekerbten Gefügen
2010
8 Seiten, 15 Quellen
Aufsatz (Konferenz)
Englisch
Aluminiumlegierung , Ermüdungslebensdauer , Ermüdungsrisswachstum , Ermüdungsverhalten , Flugzeugzelle , Kerbwirkung , Luftfahrzeug , mechanische Spannungsverteilung , mechanisches Modell , mehrachsige Spannung , Mikrostruktur , Schadensanalyse , stochastisches Modell , Strukturmodell , ungleichmäßige Beanspruchung , Vorhersagemodell , Wahrscheinlichkeitsrechnung
Fatigue behavior of notched steel specimens
TIBKAT | 1974
|Stress and Fatigue Analyses of Notched Shafts
SAE Technical Papers | 1999
|Stress and fatigue analyses of notched shafts
Kraftfahrwesen | 1999
|Fatigue crack propagation in severely notched bars
TIBKAT | 1956
|Stress and Fatigue Analyses of Notched Shafts
British Library Conference Proceedings | 1999
|