Developing a continuum damage mechanics model for creep-fatigue life assessment of a gas turbine blade

The aim of this research is to propose a procedure for predicting creep-fatigue life of gas turbine blade. Components in gas turbine hot section such combustion chamber and turbine gets damaged under effect of thermomechanical loadings. These damages developed via fatigue and creep together, thus it is necessary to identify their interaction on each other. To achieve this goal Chaboche’s elasto-viscoplastic model which is an appropriate model for simulating the behavior of nickel alloys being used. Damage evolution rules for fatigue and creep which introduced by chaboche and kachanov respectively added to viscoplastic model and implemented in Abaqus by a UMAT. After verification of Generated subroutine by a simple model, a rotor blade of last stage of a low pressure turbine was used in the process of creep-fatigue life assessment. Predicted life has proposed in three ways as the operating hours, number of starts and the equivalent operation hours which is the common ways of announcing gas turbines life. Comparison the gained results with common gas turbines life represent that this procedure’s capability and practicality.