Seismic time–frequency spectrum analysis based on local polynomial Fourier transform

2019 ◽  
Vol 68 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Pengfei Qi ◽  
Yanchun Wang
Keyword(s):  
Fourier Transform ◽  
Frequency Spectrum ◽  
Spectrum Analysis ◽  
Frequency Spectrum Analysis ◽  
Time Frequency ◽  
Local Polynomial ◽  
Local Polynomial Fourier Transform

Research on Shearer Rocker Gearbox Fault Location Based on Wavelet Envelope Demodulation

2014 ◽  
Vol 528 ◽  
pp. 210-216
Author(s):  
Zeng Qiang Wang ◽  
Hong Wei Ma ◽  
Mei Hua Tao ◽  
Xu Hui Zhang ◽  
Qing Hua Mao
Keyword(s):  
Fourier Transform ◽  
Frequency Spectrum ◽  
Spectrum Analysis ◽  
Fault Location ◽  
Vibration Signal ◽  
Morlet Wavelet ◽  
Frequency Spectrum Analysis ◽  
Mechanical Faults ◽  
Faults Diagnosis ◽  
Feature Frequency

To solve the problem of faults location for shearer rocker gearbox, the multiple sites vibration signal of faulty rocker gearbox are collected, as well as the Morlet wavelet envelope demodulation is applied to demodulate vibration signal and Fourier transform is used to carry out frequency spectrum analysis of vibration signal. Experimental results show that this method can effectively extract the faults feature frequency from complex vibration signal. The faults location result is consistent with actual faults part. This mean realizes to locate faults accurately. It provides an effective method for mechanical faults diagnosis of shearer.

Motor Fault Diagnosis Based on Wavelet Analysis and Fast Fourier Transform

2011 ◽  
Vol 301-303 ◽  
pp. 1401-1405
Author(s):  
Qing Xin Zhang ◽  
Jin Li ◽  
Hai Bin Li ◽  
Chong Liu
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Frequency Spectrum ◽  
Spectrum Analysis ◽  
Traditional Method ◽  
Engineering Application ◽  
Frequency Spectrum Analysis ◽  
Stator Current ◽  
Frequency Components ◽  
Fault Characteristic

For the detection of the broken-bar fault of rotor in motors, a traditional method is frequency spectrum analysis for the stator current. However, the frequency components representative of the rotor fault can be easily submerged by the fundamental frequency, so that the detections results are inaccurate. In this paper, the stator current will be decomposed and reconstructed, after that the fast Fourier transform can be applied to the frequency spectrum analysis. It eliminates the influence that the fault characteristic components are flooded by the basic frequency components. The experiment result shows that the existence of a slight fault in rotor can be detected. The method has a good theoretical and engineering application.

The Processing Way of Pipeline Vibration Signal Based on Wavelet Transform

2011 ◽  
Vol 317-319 ◽  
pp. 1525-1528
Author(s):  
Ji Chen Shen ◽  
Shi Rong Zhao ◽  
Jing Min Chen
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Fast Fourier Transform ◽  
Frequency Spectrum ◽  
Frequency Band ◽  
Spectrum Analysis ◽  
Vibration Signal ◽  
Scale Analysis ◽  
Frequency Spectrum Analysis ◽  
Pipeline Vibration

The vibration phenomenon of pipeline for conveying liquid and gas is very common. Based on the feature of pipeline vibration and multi-resolution of wavelet, this paper has mainly simulated the vibration signal of pipeline and made muti-scale analysis of the signal. At the same time, this paper points out that the selected frequency band which causes the vibration can be found out, by using frequency spectrum analysis of pipeline vibration signal, combined with Fast Fourier Transform (FFT).So this paper shows that the processing way of pipeline vibration signal based on wavelet transform is available.

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