Vibration Features of Titanium Alloy Blades with Erosive Damages
Journal Title: Проблеми машинобудування - Year 2018, Vol 21, Issue 4
Abstract
This paper deals with erosive damage influence on the vibration features of the working blades of the fifth-stage of the low pressure cylinder (LPC) of a K-1000-60/3000 steam turbine for a nuclear power plant (NPP). The blades are made of the TS5 titanium alloy and have a length of 1,200 mm. Notable erosive damages were observed in the fifth-stage LPC blades after more than 180,000 hours of operation at the Khmelnytska NPP, the greatest danger arising due to the formation of craters and slit-type damages. Such damage causes stress concentration, which leads to a decrease in fatigue and residual life. The radius of the erosive damage front mouth is noticeably larger than that of a fatigue crack. With such damages to the edge-to-edge contact, no damages can be observed. In the course of research, there was developed a finite-element model of a blade having a more condensed grid in the damage area, but a less condensed one in the main volume of the blade. There have been performed multivariate numerical oscillation studies of blades with different numbers of damages, which are located in different places along the blade length in the stress localization zone arising due to the features of vibration forms. There have been revealed the features of stress distribution in damage zones. It has been shown that an increase in the number of damages leads to an increase in the area of increased stresses but does not increase their concentration. There have been considered vibrations of the blades under the load of a conditional value, which made it possible to determine the real vibration stress concentration factors in the damage zones. This allows one to use the experience of analyzing the vibrations of damaged titanium alloy compressor blades. The degree of reduction of the endurance limit of damaged titanium alloy blades has been revealed. Recommendations on preventing damaged K-1000-60/3000 turbine blades from being used have been developed.
Authors and Affiliations
Yurii S. Vorobiov, Nataliia Yu. Ovcharova, Anton S. Olkhovskyi, Oleg V. Makhnenko, Vasyl M. Torop, Olena Ye. Hopkalo
Keywords
Related Articles
- EP ID EP622104
- DOI 10.15407/pmach2018.04.013
- Views 52
- Downloads 0
Influence of Lubricating-Cooling Technological Media on Metal Destruction During Cutting
The influence of lubricating and cooling technological means on the destruction of metal during cutting is shown. It has been established that the most effective additives to lubricating and cooling technological means (...
Chaotic Oscillations of a Kinematically Excited Flat Shell During Geometrically Non-linear Deformation
We study the forced oscillations of a cantilevered flat shell of constant curvature. These movements are excited by a kinematic periodic embedding motion. To describe geometrically non-linear deformation, the non-linear...
Experimental Strength Analysis of Variable Stiffness Waffel-Grid Cylindrical Compartments. Part 2. Analysis Results
This paper presents the results of the experimental analysis of the stress-strain state of the variable stiffness tail compartment (section) designed by the Yuzhnoye Design Bureau. Equivalent compressive forces in the cr...
Numerical analysis of stress-strain state of vertical cylindrical oil tanks with dents
The destruction of vertical cylindrical tanks results in both human and economic losses. Despite constant improvement of the manufacturing technology of cylindrical tanks, a complete analysis of the influence of various...
Stress Concentration in Vertical Tank Weld Seams
The article describes a new method for analyzing and predicting the stress concentration coefficient in a rolled vertical tank weld seam under hydrostatic loading. Vertical tanks are widely used for storing petroleum pro...