Bouraou N., Klofa I., Zhukovskii Y., Kulish E. Theoretical bases of vibration diagnostics of anchor against landslide constructions
Monday, 25 July 2011 09:00
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The given work is devoted to development of theoretical bases of a new vibrating diagnostics method and evaluation a current condition of the anchor. The research of the pulse response of the anchor against landslide construction is a basis of vibrating diagnostics of a tension condition an anchor, detection of feature of abatement of a tightness, and definition of character of its dependence on a changing stretching force. The elastic body with the distributed parameters (a string) is used as the diagnostic model of the tense and fixed core of an anchor. Dependences of own frequencies changing of the pulse response of an anchor on a tightness changing at deformations and displacement of a place of fastening of an anchor are defined. The discrete model of an anchor against landslide construction is developed and researched for definition of dependences between parameters of an anchor condition and vibrating characteristics of a retaining wall, which is accessible to carrying out of measurements. Bouraou N., Protasov A., Sopilka Yu., Zazhitsky O., Decision making of aircraft engine blades condition based on bispectral analysis of the vibroacoustical signal
Friday, 22 July 2011 17:42
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In this paper the simulation of vibroacoustical signals radiated by the engine turbine at the stationary vibration excitation is carried out for situations when all turbine blades have no defects and one blade has a small fatigue crack. Bispectral analysis is used for diagnostic information processing. It demonstrates that appearance and evolution of the fatigue crack in a blade change intensity of global and local extremums of bispectral modules. The results of bispectral processing and Probability Neural Network (PNN) are used to recognize of the turbine blades condition. The efficiency factor is used for precision analysis. Bouraou N., Sopilka I. Vibroacoustical diagnosis of the cracklike damages of aircraft engine blades at the steadystate and nonsteadystate modes
Monday, 25 July 2011 08:50
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The work is devoted to condition monitoring and vibroacoustical diagnosis of the cracklike damages of the gasturbine engines (GTE) blades at the steadystate and nonsteadystate modes of GTE. The developed diagnostic model of GTE is presented and the influence of damage on the measured vibro and acoustical signals at the steadystate and nonsteadystate modes of GTE is determined. The application of the following signal processing methods: Polyspectral (HigherOrder Spectral) analysis, Wavelettransformation and dimensionless characteristics of the vibroacoustical signals is proved. The efficiency of signal processing methods is demonstrated by the results of numerical simulations of the turbine stage at the steadystate and nonsteadystate modes of vibration excitation. The fault features are detected and investigated. Bouraou N., Tyapchenko A. Statistical Characterization of Estimates of Relative Crack Dimensions Based on the Method of Higher Harmonics
Monday, 25 July 2011 08:58
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Fatigue cracks are diagnosed and characterized using a vector of parameters composed of the ratios between spectral amplitudes of the higher and fundamental harmonics in inherent acoustic modes of an object. Using the method of maximal likelihood, we have obtained estimates of the relative crack dimensions and analyzed their statistical characteristics depending on the composition of the parameter vector and noise intensity in measurements. Bouraou N., Zsukovskij Y., Kulish E., Ryzshij M. Information and measuring system for monitoring of buildings and constructions under the influence of microseismic oscillations
Monday, 25 July 2011 08:53
administrator
The work is devoted to problem solution of the gasturbine engines (GTE) blades condition monitoring and diagnosis of the cracklike damages at the steadystate and nonsteadystate modes of GTE. It is based on the development of theoretical basis of the vibroacoustical diagnosis methods, the application of the modern signal processing methods and new information technique for decision making. The application of the following signal processing methods: Wavelettransformation and dimensionless characteristics of the vibroacoustical signals is proved. The neuron networks are used for decision making about blades condition by the above mentioned features application. Classification of turbine blade condition was carried out using a twolayer Probability Neural Network (PNN). 



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