Multi-component signal decomposition techniques for structural health monitoring

Abstract

Most structural responses can be considered as the superposition of some monotonic components. These monotonic components contain modal information that can be used for structural damage detection and health monitoring. This paper presents a comparative study of three techniques for signal decomposition and analysis. These techniques are the wavelet transform (WT) technique, the empirical mode decomposition (EMD) technique, and the principle component analysis (PCA) technique. These techniques are all capable of decomposing multi-component signals into a summation of mono-components without resorting to the traditional frequency-domain approach. All three techniques can estimate natural frequencies, damping ratios and mode shapes of a structure from its time-domain vibration responses and hence can be used to monitor structural condition. A numerical study on a three-story shear-beam building frame is performed and presented to show the accuracy of these techniques.