Fatigue Life Analysis Based on Transition State Parameters of Turbine Blades

ANSYS finite element analysis software is used to calculate the fatigue life of a certain turbine blade during the thermal shock process in this paper. The various state parameters of the turbine blades during the thermal shock process are calculated and analyzed. The changes in temperature, stress, and strain of the turbine blade at various locations during the thermal shock process are obtained. The stress and strain results obtained from various monitoring points are used to calculate the fatigue life using the local stress–strain method. A thermal shock test bench is established to conduct thermal shock fatigue tests on the blades. The full life formula is used to calculate the blade’s crack propagation life. The stress and strain changes at various points near the leading edge of the blade during the thermal shock process are similar to the trend of gas temperature changes. The point of maximum stress and strain appears at the leading edge of the blade. The location of fatigue failure first appears near the leading edge of the blade, with fatigue damage traces also found at the trailing edge of the blade. Using the full life formula, the estimated crack propagation life of the blade is approximately 3500–4500 cycles. The total life is estimated to be approximately 6500–7500 cycles. The fatigue life calculation method based on transitional state parameters can significantly reduce the number of thermal shock experiments and calculate the fatigue life at each stage of the turbine blade.