Djavanroodi - Tehran University IRAN
Etemad - Imperial College,London , SW۷ ۲BX U.K
Nikbin - Imperial College,London , SW۷ ۲BX U.K

In the power generation industry the possibility of catastrophic failure exists increasing age of the plant. During the components' service life failure problems at high temperatures under static and cyclic loading become a relevant safety and economic factor that must be considered. Several methods and international standards are available for estimating the creep/fatigue failure rates of these components. This paper considers the linear and non-linear fracture mechanics concepts applied to laboratory results to show the methodology available for life prediction at high temperatures. Creep/fatigue failures are determined in terms of stress intensity factor K and the creep parameter C*. Using experimental data, which makes use of limit analysis concepts and requires little knowledge of the creep strain behaviour of materials a relationship of cracking rate in terms of C* is shown. Method of estimating C* is presented and a model to predict failure is shown to satisfactorily predict high temperature cracking behaviour in engineering alloys.