Research On Structural Damages Identification Based On Experimental Modal And Wavelet Analysis

For many reasons the structures may appear the damage during the actual operation process, In order to safeguard the security, integrity and the durability of the structure, it's necessary to carry on the health monitoring, and the most coral content is the structural damage identification. Damage diagnosis technique is an active research area in current engineering and has widely engineering foreground. The correlative theory and technology are developing continuously.Wavelet analysis is a relatively new mathematical and signal processing tool. It is a time frequency technique that provides more detailed information about nonstationary signals, which is superior to the traditional frequency domain Fourier analysis. Wavelet analysis has been applied to various fields, especially damage detection and structural health monitoring. This method can efficiently extract the feature of damage and can precisely predict crack. Mode signals can be analyzed by continuous wavelet transformed to find a crack at an extent in an arch, and also the crack can be located.The experiment results show that wavelet transform can locate the position of the crack exactly. This method is also in effect to light noisy signal. It demonstrates that wavelet transform has a certain characteristics of anti-noise.Experimental modal an analysis (EMA) has become an increasingly accepted method for determining the overall health of a structure. It uses differences of measured modal properties from baseline or nominal values to identify and assess the location and severity of damage.Based on experimental modal analysis, we use COMAC method to study a damaged cantilevered beam. The results show that the method can tested location and extend of damage.Based on the above researches, the advantages and limitations of the presented method as well as suggestions for future work are presented and discussed.