基于 Wiener 过程的涡轮盘榫槽裂纹扩展可靠性分析

A time-varying model considering crack growth degradation process was established and applied to the probabilistic life analysis of crack growth in the turbine disk mortise. Firstly, a time-varying crack growth model of GH4720Li superalloy was established by introducing the Wiener stochastic process with double time scale functions. And it was verified by crack growth test of compact tensile specimens. Then, taking the root of the turbine disk’s mortise tooth as the key object, the weight function method for solving the stress intensity factor of the crack in the root of the turbine disk’s mortise tooth was established and compared with the finite element analysis results of the crack growth in the turbine disk mortise. Finally, combining the weight function and the time-varying crack growth model, the reliability analysis method for fatigue crack growth degradation of the turbine disk mortise was established. Analysis results showed that the crack growth degradation life of the turbine disk’s mortise presented a large dispersion, with an average value of 14 177 cycles and a standard deviation of 1 090.09 cycles. The prediction of crack growth life was 10 312 cycles when the reliability was 99.87%.