Durability diagnostics of turbine blades based on non-destructive acoustic emission testing

摘要

Acoustic Emission (AE) method for material state monitoring during fatigue tests was attested for turbine blade durability estimation for different types of superalloys. Average value of summarized AE signals, N_(ae), registered during the beginning of tests and summarized AE-signals, (N_(ae))_(01), in the second semi-cycle of blade bending both have good correlation with durability that blades reached at the moment of fracture. The discovered relations between summarized AE signals and durability demonstrated the high value of the correlation factor. For the moment of crack origination, the number of cycles, (N_f)_a, can be simulated also by the AE signals, (N_(ae))_t, registered during time interval in several minutes. In all discussed cases, relations between parameters of AE signals and critical values of the cycle's number for estimating durability introduced with discovered factors.