LAUSR

This paper discusses the determination of the optimum decomposition level by using the discrete wavelet transform (DWT) method for an automobile suspension system. The DWT method has been widely adopted in signal processing analyses. For the purpose of this study, a car was driven on two types of road conditions: highway and bumpy. Strain signals were measured based on the response gained from the coil spring. These signals were decomposed into 14 levels of decomposition, in which the percentage of wavelet energy for Levels 1 through 4 were 100 % similar to the original signals for both roads. The results were evaluated by comparing the fatigue life values for each decomposition level to the original signal. Based on the comparison of both roads, levels 1 to 3 show a difference of less than 20 % in fatigue life compared to the original signal. Thus, the accuracy of wavelet-based signal processing has proven to be applied in the fatigue durability analysis for automotive applications.