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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 293-294 (Sept. 2005), p. 475-482 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Model based fault identification techniques can be used to diagnose local faults in rotating machinery; the equivalent loads that represent fault forces can be used to identify the fault location. But in some cases the equivalent loads smeared over many nodes, and make it hard to identify accurate fault location and transient fault force. In this paper, the fault location is identified using least squares fitting approach by the system’s vibration shape when the fault signal is periodic or quasi-periodic. And after the fault location is ascertained, the transient fault forces can be identified by transient residual vibration using simple matrix multiplications and additions. Numerical simulations and experiment on rotor to stator rub are used to test the method, which proved the efficiency of the method
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 353-358 (Sept. 2007), p. 2463-2466 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Rotating machinery, such as steam turbo, compressor, and aeroengine etc., are widely usedin many industrial fields. Among the important rotor faults, the fatigue crack fault, which can lead tocatastrophic failure and cause injuries and severe damage to machinery if undetected in its earlystages, is most difficult to detect efficiently with traditional methods. In the paper, based on the truthof the change of the mode shapes of the cracked structure, a new method by combining accurate finiteelement model of rotor with multi-crack in shaft and artificial neural network (ANN) is proposed toidentify the location and depth of cracks in rotating machinery. First, based on fracture mechanics andthe energy principle of Paris, the accurate FE model of the rotor system considering several localizedon-edge non-propagating open cracks with different depth, is built to produce the specific modeshapes. Then a set of different mode shapes of a rotor system with localized cracks in several differentpositions and depths, which will be treated as the input of the designed ANN model, can be obtainedby repeating the above step. At last, with several selected crack cases, the errors between the resultsobtained by using the trained ANN model and FEM ones are compared and illustrated. Meanwhile,the influences of crack in the different position on the identification success are analyzed. The methodis validated on the test-rig and proved to have good effectiveness in identification process
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 353-358 (Sept. 2007), p. 2289-2292 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Structural damage often happens in rotating machinery such as steam engines, aircraftengines, and compressors due to the high-speed rotating of the shaft. The most common structuraldamages in rotating machinery are rotor shaft crack, rotor to stator rub, and bolts looseness and soon. In the present paper, the model based identification method is used to detect single structuraldamage such as crack, rotor to stator rub, pedestal looseness, and also, coupling fault such as rotorto stator rub and crack, crack and pedestal looseness. Utilizing the characteristic that equivalentloads of rub forces are internal forces, and the equivalent loads of the crack are external moments,the coupling faults of crack and rub-impact and crack and pedestal looseness are analyzed andexampled. The merit of the method is that it is an online diagnosis method, which provides earlywarning of machine failure. Theoretical simulation and laboratory testing are conducted to validatethe method
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 353-358 (Sept. 2007), p. 1683-1687 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A continuum model of the evolution of air ingestion and entrainment for open-endedsqueeze film dampers is proposed in this paper. Hydrodynamic lubrication theory is extended tolubrication with mixture of a Newtonian liquid and an ideal gas. The solution to the universalReynolds equation is determined numerically using a control volume method (Elrod algorithm) andthe forth-order Range-Kutta method. This method conserves mass throughout the computationaldomain including air ingestion and entrainment. Excellent agreement is found with the experimentalworks of Diaz and San Andrès for the squeeze film damper [1, 2]
    Type of Medium: Electronic Resource
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