Multiresolution Wavelet Analysis of the Dynamics of a Cracked Rotor

We examine the dynamics of a healthy rotor and a rotor with a transverse crack, which opens and closes due to its self weight. Using discrete wavelet transform, we perform a multiresolution analysis of the measured vibration signal from each of these rotors. In particular, the measured vibration signal is decomposed into eight frequency bands, and the rms amplitude values of the healthy and cracked rotors are compared in the three lowest-frequency bands. The results indicate that the rms vibration amplitudes for the cracked rotor are larger than those of the healthy rotor in each of these three frequency bands. In the case of externally applied harmonic force excitation to the rotor, the rms values of the vibration amplitude of the cracked rotor are also found to be larger than those of a healthy rotor in the three lowest-frequency bands. Furthermore, the difference in the rms values between the healthy and cracked rotors in each of the three lowest-frequency bands is more pronounced in the presence of external excitation than that with no excitation. The obtained results suggest that the present multiresolution approach can be used effectively to detect the presence of a crack in a rotor.

[1]  Xi Wu,et al.  Vibration-based crack diagnosis in rotating shafts during acceleration through resonance , 2003, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[2]  Xi Wu,et al.  Application of nonlinear dynamics tools for diagnosis of cracked rotor vibration signatures , 2005, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[3]  Grzegorz Litak,et al.  Cracked rotor detection by recurrence plots , 2009 .

[4]  Gang Qi,et al.  Discrete wavelet decomposition of acoustic emission signals from carbon-fiber-reinforced composites , 1997 .

[5]  A. S. Sekhar,et al.  CRACK DETECTION THROUGH WAVELET TRANSFORM FOR A RUN-UP ROTOR , 2003 .

[6]  J. Kulkarni,et al.  Wavelet analysis of the association between the Southern Oscillation and the Indian summer monsoon , 2000 .

[7]  A. S. Sekhar,et al.  Model-based identification of two cracks in a rotor system , 2004 .

[8]  A. S. Sekhar,et al.  Crack identification in a rotor system: a model-based approach , 2004 .

[9]  Xi Wu.  FINITE ELEMENT ANALYSIS OF COUPLED LATERAL AND TORSIONAL VIBRATIONS OF A ROTOR WITH MULTIPLE CRACKS , 2005 .

[10]  Dan Guo,et al.  Vibration analysis of a cracked rotor using Hilbert–Huang transform , 2007 .

[11]  B. O. Al-Bedoor,et al.  WAVELET ANALYSIS OF VIBRATION SIGNALS OF AN OVERHANG ROTOR WITH A PROPAGATING TRANSVERSE CRACK , 2001 .

[12]  R. Gordon Kirk,et al.  Cracked shaft detection and diagnostics: A literature review , 2004 .

[13]  Steven Hector Azzaro,et al.  Development of an On-Line Rotor Crack Detection and Monitoring System , 1989 .

[14]  Yukio Ishida.  Cracked rotors: Industrial machine case histories and nonlinear effects shown by simple Jeffcott rotor , 2008 .

[15]  Hiroaki Hatanaka,et al.  Ultrasonic testing with advanced signal processing for concrete structures , 2005 .

[16]  Shyh-Chin Huang,et al.  In-Plane Vibration and Crack Detection of a Rotating Shaft-Disk Containing a Transverse Crack , 1998 .

[17]  J. B. Ramsey,et al.  DECOMPOSITION OF ECONOMIC RELATIONSHIPS BY TIMESCALE USING WAVELETS , 1998, Macroeconomic Dynamics.

[18]  R. Gasch,et al.  A Survey Of The Dynamic Behaviour Of A Simple Rotating Shaft With A Transverse Crack , 1993 .

[19]  G. T. Zheng,et al.  Vibration of a Rotor System With a Switching Crack and Detection of the Crack , 1998 .

[20]  Amiya R Mohanty,et al.  DETECTION AND MONITORING OF CRACKS IN A ROTOR-BEARING SYSTEM USING WAVELET TRANSFORMS , 2001 .

[21]  Charles R. Farrar,et al.  Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: A literature review , 1996 .

[22]  D.J. Inman,et al.  Damage detection of a rotating cracked shaft using an active magnetic bearing as a force actuator - analysis and experimental verification , 2005, IEEE/ASME Transactions on Mechatronics.

[23]  Andrew D. Dimarogonas,et al.  Vibration of cracked structures: A state of the art review , 1996 .

[24]  H. Lundstedt.  Wavelet reconstructions of solar magnetic activity , 2006 .

[25]  Michael I. Friswell,et al.  Condition Monitoring of Rotor Using Active Magnetic Actuator , 2008 .

[26]  H. Adeli,et al.  Analysis of EEG records in an epileptic patient using wavelet transform , 2003, Journal of Neuroscience Methods.

[27]  David A. Robb,et al.  The Dynamics of a Cracked Rotor With an Active Magnetic Bearing , 2001 .

[28]  Jerzy T. Sawicki,et al.  Rotor Crack Detection Using Active Magnetic Bearings , 2008 .

[29]  D. Dane Quinn,et al.  Active health monitoring in a rotating cracked shaft using active magnetic bearings as force actuators , 2006 .

[30]  John E. T. Penny,et al.  Condition Monitoring of Rotating Machinery using Active Magnetic Bearings , 2006 .