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Journal Article 2

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2020 1

2008 1

Keywords

acoustic emission 1

ambient vibration test 1

cross and autocorrelation of wavelets 1

fault diagnosis 1

feature extraction 1

high level noise 1

iterative signal enhancement 1

rolling bearing 1

wavelet 1

wavelets scalogram 1

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Application of wavelet scalogram in feature extraction of acoustic emission signal

Xiao Siwen,Liao Chuanjun,Li Xuejun

Strategic Study of CAE 2008, Volume 10, Issue 11,   Pages 69-75

Abstract: Wavelet scalogram has a particular time-frequency localization, which helps it to be well used for describinganalyzing the characteristics and feature extraction of typical AE signals, the paper applies wavelet scalogramfor fault diagnosis based on AE technique, and presents the wavelet scalogram analysis method of AESo the limitation that best time resolution and frequency resolution of wavelet scalogram cannot getWhen applying wavelet scalogram for fault diagnosis of rolling bearings based on AE techniques, the results

Keywords： wavelets scalogram     acoustic emission     feature extraction     fault diagnosis     rolling bearing    

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Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient vibration tests in Shiraz-Iran

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

Frontiers of Structural and Civil Engineering 2020, Volume 14, Issue 2,   Pages 446-472 doi: 10.1007/s11709-019-0605-8

Abstract: The main purpose of the present study is to enhance high-level noisy data by a wavelet-based iterative filtering algorithm for identification of natural frequencies during ambient wind vibrational tests on a petrochemical process tower. Most of denoising methods fail to filter such noise properly. Both the signal-to-noise ratio and the peak signal-to-noise ratio are small. Multiresolution-based one-step and variational-based filtering methods fail to denoise properly with thresholds obtained by theoretical or empirical method. Due to the fact that it is impossible to completely denoise such high-level noisy data, the enhancing approach is used to improve the data quality, which is the main novelty from the application point of view here. For this iterative method, a simple computational approach is proposed to estimate the dynamic threshold values. Hence, different thresholds can be obtained for different recorded signals in one ambient test. This is in contrast to commonly used approaches recommending one global threshold estimated mainly by an empirical method. After the enhancements, modal frequencies are directly detected by the cross wavelet transform (XWT), the spectral power density and autocorrelation of wavelet coefficients. Estimated frequencies are then compared with those of an undamaged-model, simulated by the finite element method.

Keywords： ambient vibration test     high level noise     iterative signal enhancement     wavelet     cross and autocorrelation of wavelets    

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Title Author Date Type Operation

Application of wavelet scalogram in feature extraction of acoustic emission signal

Xiao Siwen,Liao Chuanjun,Li Xuejun

Journal Article

Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient vibration tests in Shiraz-Iran

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

Journal Article