The invention relates to a method for predicting the high-low-cycle composite fatigue crack growth life of a
turbine joggle structure, and the method comprises the steps: (1), building a crack
growth model giving consideration to a
crack closure effect; (2), determining a high-cycle load
stress intensity factor model; (3), determining a low-cycle load
stress intensity factor model; (4), judging whether a
current cycle is a high-cycle load or not: executing step (5) if the
current cycle is the high-cycle load, or else executing step (6); (5), calculating a composite fatigue lower crack increment, judging whether a next cycle is a low-cycle fatigue load or not: obtaining the maximum
crack tip opening displacement of the
current cycle if the next cycle is the low-cycle fatigue load, and executing step (7), or else executing step (8); (6), calculating the variance of the low-cycle load lower
crack tip opening displacement; (7), calculating the residual
crack tip opening displacement and crack increment according to the results inputted at steps (5) and (6); (8), updating the crack length, repeatedly carrying out the steps (4)-(7) if the maximum
stress intensity factor is less than the
fracture toughness, or else completing the calculation, and obtaining the crack growth life.