Time-Frequency Modeling and Analysis of Faulty Rotor
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 32771
Time-Frequency Modeling and Analysis of Faulty Rotor

Authors: B. X. Tchomeni, A. A. Alugongo, T. B. Tengen

Abstract:

In this paper, de Laval rotor system has been characterized by a hinge model and its transient response numerically treated for a dynamic solution. The effect of the ensuing non-linear disturbances namely rub and breathing crack is numerically simulated. Subsequently, three analysis methods: Orbit Analysis, Fast Fourier Transform (FFT), and Wavelet Transform (WT) are employed to extract features of the vibration signal of the faulty system. An analysis of the system response orbits clearly indicates the perturbations due to the rotor-to-stator contact. The sensitivities of WT to the variation in system speed have been investigated by Continuous Wavelet Transform (CWT). The analysis reveals that features of crack, rubs and unbalance in vibration response can be useful for condition monitoring. WT reveals its ability to detect nonlinear signal, and obtained results provide a useful tool method for detecting machinery faults.

Keywords: Continuous wavelet, crack, discrete wavelet, high acceleration, low acceleration, nonlinear, rotor-stator, rub.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1110537

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1653

References:


[1] A. S. Sekhar, Crack identification in a rotor system: a model- based approach. Journal of sound and vibration 270, 2004, 887-920.
[2] R. Gasch, IMechE Conference Publication c178/76, 1976, 123-128. Dynamic behavior of a simple rotor with cross-sectional crack.
[3] A. D. Dimaragonas and C. A. Papadopoulos, Journal of Sound and Vibration 91, 1983, 583-593. Vibration of cracked shafts in bending.
[4] C. A. Papadopoulos and A. D. Dimaragonas, Journal of Sound and Vibration 117, 1987, 81-93. Coupled longitudinal and bending vibrations of a rotating shaft with an open crack.
[5] M.I. Friswellc, J.K. Sinhaa, A.W. Leesb, Journal of Sound and Vibration 272 (2004) 967–989. Estimating unbalance and misalignment of a flexible rotating machine from a single run-down.
[6] A. S. Sekhar, and B. S. Prabhu, Condition monitoring of cracked rotor through transient response, 1998 Mech. Mach. Theory 33, 1167-1175.
[7] B.X. Tchomeni, A.A. Alugongo, L.M. Masu, In situ Modelling of Lateral-Torsional Vibration of a Rotor-Stator with Multiple Parametric Excitations. World Academy of Science, Engineering and Technology International Journal of Mechanical, Aerospace, Industrial and Mechatronics Engineering Vol: 8 No: 11, 2014.
[8] B. O. Al-bedoor, Transient torsional and lateral vibrations of unbalanced rotors with rotor-to-stator rubbing. Journal of Sound and vibration 229(3), 2000, 627-645.
[9] R. Sukkar, and A.S. Yigit, Analysis of fully coupled torsional and lateral vibrations of unbalanced rotors subject to axial loads. Kuwait J.Sci.Eng.35 (2B), 2008, pp. 143-170.
[10] J.-J. Sinou, “An experimental investigation of condition monitoring for notched rotors through transient signals and wavelet transform” 2009.
[11] S. Prabhakar, A. S. Sekhar and A. R. Mohanty, Mechanical Systems and Signal Processing 15, 2001, 447-450. Detection and monitoring of cracks in a rotor-bearing system using wavelet transforms.
[12] A. A. Alugongo, A dual Time-Frequency-Feature investigation and diagnostics of a cracked de-Laval rotor. IEEE AFRICON 2009.
[13] I. Daubechies, “Orthonormal bases of compactly supported wavelets,” Communication on Pure and Applied Mathematics, vol. 41, pp. 909-996, 1988.
[14] S. Mallat, A wavelet Tour of Signal Processing, Academic Press, San Diego 1998.