Open Access

ARTICLE

Extraction of Fatigue Damaging Events from Road Spectrum Loadings Using the Wavelet-Based Fatigue Data Editing Algorithm

by ,

1 Department of Mechanical and Materials Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia. Email: shahrum@eng.ukm.my

Structural Durability & Health Monitoring 2008, 4(4), 181-198. https://doi.org/10.3970/sdhm.2008.004.181

Abstract

This paper describes a technique to identify the important features in fatigue road spectrum loading, for which these features cause the majority of the total damage. Fatigue damaging events, called bump segments, are extracted from the spectrum loading using a wavelet-based algorithm, called Wavelet Bump Extraction (WBE). This algorithm is also used to produce a shortened mission signal that retains most of the fatigue damage whilst preserving the cycle sequences. The bump identification process has been evaluated by analysing two road spectrum loadings having a variable amplitude pattern. These data sets were obtained from the strain measurement on the lower suspension of different vehicles travelling over different road surfaces. In this study the total fatigue life caused by the combination of all bump events was close to the original data sets. For this case, the fatigue life of the original spectrum loading and the WBE extracted loadings are predicted using three strain-life fatigue damage models, i.e. the Coffin-Manson relationship, the Morrow and the Smith-Watson-Topper (SWT) mean stress correction effects. In addition, the correlation analysis showed that the coefficient of variation (R²) between the fatigue lives of the original and the total of bump segments was found to be 99.9% or 0.999. These findings suggested that WBE is a suitable approach for mission synthesis applications by producing a shortened mission signal for accelerated fatigue test.

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Keywords

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