Short-life turbine blade rack extension analysis and life prediction

For the short-life turbine blade, the low-fatigue test results do not match with the numerical simulation, and other factors are investigated and attributed to material and structural defects. The fracture mechanics life prediction method is used for life prediction, and the crack extension results of the defective turbine blade are obtained by combining the FRACN3D software and the low-week fatigue test to get the fatigue life and crack extension length-load cycle number (a-N) curves of the turbine blade. The results show that: through the fracture mechanics numerical simulation to derive the crack tip expansion path test is consistent with the turbine blade from 4mm crack expansion to 5mm with 43 load cycles, and the difference with the results of the low weekly fatigue test is small, the error is only 14%, from the 5mm crack length expansion to the turbine blade failure with 40 cycles, based on the defective turbine blade with a 4mm crack the remaining life of the turbine blade is 83 cycles, the remaining life of the defective turbine blade is 83 cycles based on a 4 mm crack, and the total number of loading cycles from crack initiation to crack failure is 133, which provides an analytical method for the design of damage tolerance and remaining life of the turbine blade.