Probabilistic Material Degradation under High Temperature, Fatigue, and Creep

摘要: This paper describes the development of methodology that provides for quantification uncertainty in lifetime material strength degradation structural components aerospace propulsion systems subjected to a number diverse random effects. The is embodied two computer programs PROMISS and PROMISC. These form material-resistance model used an structural-reliability program NESSUS. A probabilistic material-degradation model, postulated randomized multifactor interaction equation, quantify strength. Each multiplicative term has property if current value effect equals ultimate value, then will be zero. Also, reference one not affected by particular effect. Presently, includes three effects typically reduce strength: high temperature, mechanical fatigue, creep. also statistical analysis experimental data INCONEL 718 obtained from open literature. provided regression parameters use as empirical constants thus calibrating specifically 718. Model calibration was carried out variables, namely, Finally, using program, sensitivity study performed with calibrated illustrating each variable upon