Acoustic emission used for detection of crack generation in propellers of turbine-pump units

The problem of applying acoustic emission (AE) for detection of crack generation in heavily loaded elements of rotor systems, in particular, in propellers of turbine-pump units, in which breakdown of propellers during the operation is possible because of fatigue-crack generation, is studied. The data on AE signals radiated from some materials of the propellers exposed to monotonic and cyclic loading are presented, and the possibilities of emission and detection of AE signals with setups built in the rotor system construction are determined. Two developed setups are compared, one of which is characterized by high reliability, sufficient sensitivity to crack generation, and the absence of electronic amplifiers and power supply units. The design and results of the tests performed with this setup for AE-technique-based monitoring of the crack formation are presented.