Identification of Vibration Characteristics Parameters Based on Morlet Wavelet Transformation

Abstract:

Traditional identification methods of vibration system characteristics are not capable to process nonlinear and non stationary signal,especially the low precision for identifying the damping ratio.An approach to identify the characteristics parameters of vibration system combining on random decrement technique and Morlet wavelet transform is proposed. Firstly, the free decay vibration response signal was extracted by random decrement technique(RDT), and then signal was processed to give a continuous wavelet transform by the Morlet wavelet transform to get wavelet energy spectrum.Combined the basic theory of parameter identification and semi logarithmic and curve fitting result in time frequency coordinate plane, frequency and damping ratio of the vibrating system was got.The numerical simulation result that the proposed method can accurately estimate system natural frequencies and damping ratios. The method was applied for experimental study of tanker liquid solid coupling model, the natural frequency and damping ratio of vibration system structure in loaded water conditions were well identified.