Sequential damage detection based on the continuous wavelet transform

2015 ◽  
Author(s):  
Yizheng Liao ◽  
Konstantinos Balafas ◽  
Ram Rajagopal ◽  
Anne S. Kiremidjian
Keyword(s):  
Wavelet Transform ◽  
Damage Detection ◽  
Continuous Wavelet Transform ◽  
Continuous Wavelet

ON-LINE HEALTH MONITORING AND DAMAGE DETECTION OF STRUCTURES BASED ON THE WAVELET TRANSFORM

2008 ◽  
Vol 08 (03) ◽  
pp. 367-387 ◽  
Author(s):  
B. ZHU ◽  
A. Y. T. LEUNG ◽  
C. K. WONG ◽  
W. Z. LU
Keyword(s):  
Wavelet Transform ◽  
Damage Detection ◽  
Discrete Wavelet Transform ◽  
Health Monitoring ◽  
Continuous Wavelet Transform ◽  
Abrupt Change ◽  
Discrete Wavelet ◽  
Continuous Wavelet ◽  
Random Decrement Technique ◽  
On Line

Presented herein is an experiment that aims to investigate the applicability of the wavelet transform to damage detection of a beam–spring structure. By burning out the string that is connected to the cantilever beam, high-frequency oscillations are excited in the beam–spring system, and there results an abrupt change or impulse in the discrete-wavelet-transformed signal. In this way, the discrete wavelet transform can be used to recognize the damage at the moment it occurs. In the second stage of damage detection, the shift of frequencies and damping ratios is identified by the continuous wavelet transform so as to ensure that the abrupt change or impulse in the signal from the discrete wavelet transform is a result of the damage and not the noise. For the random forced vibration, the random decrement technique is used on the original signal to obtain the free decaying responses, and then the continuous wavelet transform is applied to identify the system parameters. Some developed p version elements are used for the parametric studies on the first stage of health monitoring and to find the damage location. The results show that the two-stage method is successful in damage detection. Since the method is simple and computationally efficient, it is a good candidate for on-line health monitoring and damage detection of structures.

Damage Detection of a Gear with Initial Pitting Using the Zoomed Phase Map of Continuous Wavelet Transform

2006 ◽  
Vol 306-308 ◽  
pp. 223-228 ◽  
Author(s):  
Sang Kwon Lee ◽  
Jang Sun Shim ◽  
Byung-Og Cho
Keyword(s):  
Wavelet Transform ◽  
Damage Detection ◽  
Continuous Wavelet Transform ◽  
Vibration Signal ◽  
Phase Lag ◽  
Continuous Wavelet ◽  
Local Damage ◽  
Abrupt Increase ◽  
Phase Map

Impulsive vibration generated by localized gear damage can be used as an indicator for damage detection. Local damage induces an abrupt increase of the amplitude and phase lag of the impulsive vibration signal measured on the gearbox. Relatively large damage like “tip breakage” can be easily detected by the amplitude map of CWT (continuous wavelet transform) for the impulsive vibration signal measured on the gearbox. However, minor damage like “initial pitting” cannot be detected with the amplitude map. To overcome this problem, in this paper we take into account the phase map for a damage signal. The zoomed phase map of CWT is successfully applied to the detection of minor gearbox damage.

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