Fatigue Damage and Creep Modeling of Combined Rotor and Its Application

With the improvement of low cycle fatigue Basic test technology, the main failure modes of engine turbine blades have changed from static strength failure to vibration fatigue failure. In order to determine the vibration stress level of turbine blade in working state, it is necessary to measure the vibration stress of turbine blade on the basis of numerical calculation. In this paper, the theory and technology of Aero-engine Turbine blade dynamic stress measurement are studied and applied to a certain type of engine. Three vibration signal processing methods, namely, amplitude domain analysis method, Fourier analysis method and order analysis method, are mainly studied for turbine blade dynamic stress measurement. Based on the resonance theory and the working characteristics of turbine blades, the natural frequencies, modes, exciting forces and resonances of turbine blades are analyzed. Under low-cycle fatigue load, the increase of strain amplitude or temperature shortens the low-cycle fatigue life of rotor steel. Based on the plastic strain-cycle cycle curve of the specimen after experiment, the low-cycle fatigue life model of rotor steel is obtained by linear fitting and formula derivation. Through the calculation and verification of the model, the model can predict the low cycle fatigue life of rotor steel more accurately.