Vibration of Titanium Blades of Turbomachines for Nuclear Power Plants with Erosive Damage

The influence of erosion damages on the vibration features of the working titanium blades of the last stage of the steam turbine with a capacity of 1 GW for a nuclear power plant is considered. Erosion damages of these blades were observed after 180 thousand hours of operation. Morphological and fractographic studies have shown the nature of erosion damages, but did not reveal degradation of the mechanical properties of the material. Such damages cause the stress concentration, that leading to a decrease of fatigue limit and residual life. A finite element model of the blade has been developed, which has a denser mesh in the area of damage. Numerical studies have revealed features of stress concentration in the damages zone. The degree of reduction of blade fatigue and residual life is determined. It is shown that mechanical treatment of the erosion damage zones allows to increase the fatigue limit and residual resource.