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Wavelet analysis of shock and vibration on the truck bed
Author(s) -
Nei Daisuke,
Nakamura Nobutaka,
Roy Poritosh,
Orikasa Takahiro,
Ishikawa Yutaka,
Kitazawa Hiroaki,
Shiina Takeo
Publication year - 2008
Publication title -
packaging technology and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 50
eISSN - 1099-1522
pISSN - 0894-3214
DOI - 10.1002/pts.836
Subject(s) - vibration , shock (circulatory) , fast fourier transform , wavelet , wavelet transform , acoustics , fourier transform , harmonic wavelet transform , mathematics , discrete wavelet transform , structural engineering , computer science , engineering , algorithm , mathematical analysis , physics , artificial intelligence , medicine
Vibrations are usually analysed by the fast Fourier transform (FFT) algorithm, and this method is efficient for analysing frequency characteristics of vibrations during transportation. However, the nature of vibrations during transportation is non‐stationary, and the FFT method is not sufficient for dealing with such a non‐stationary, time‐dependent data in some cases. In this study, vibration data were analysed for non‐stationary events using a wavelet algorithm. Although apparent changes in frequency characteristics of vibrations were not observed, a continuous wavelet transform sufficiently detected the time dependence of frequency characteristics. When strong shocks were contained in vibration data, wavelet power spectra were significantly increased corresponding to shocks, and the changes were over a wide range of frequencies. The analysis using discrete wavelet transform indicated that shock signals were located in several decomposition levels, and this was dependent on shock direction. Locally amplified detail coefficients and a subsequent reconstruction successfully generated shock‐added vibration data, considering the frequency characteristics of actual shocks. This procedure is expected to be used as a shock generation method in vibration tests. Copyright © 2008 John Wiley & Sons, Ltd.