Investigation On The Modal Parameters Identification Method And Its Application

Modal parameter identification of structures plays an important role in the experimental modal analysis, since the modal parameters indicate structural dynamic characteristics to a great extent. Modal parameter identification is widely used in various engineering practices such as structral dynamic characteristic analysis, optimal structural design and so on. As modal parameter identification is based on the measured data of system's input-output signal, the data is contaminated by noise inevitably, that will reduce parameter identification precision greatly. This paper mainly includes the following contents:1. Two dynamical simulation model systems are established by using the software of Matlab/Simulink. By inputting each system a series of input signals which can simulate hammer impact process, and introducing various noises to the system response, the modal parameters for each system are then identified with those input-output data by both ERA and LSCE identification methods.2. Frequency domain average method and wavelet analysis theory are applied to the system modal parameters identification. The identification results indicate that both frequency domain average and wavelet filter methods can improve the precision of modal parameters identification, while wavelet analysis is the most effective in damp identification.3. Based on section model wind tunnel test, modal identification techniques including ERA, LSCE and Wavelet are utilized to determine the flutter derivatives of a bridge deck section. Up to now, the application of LSCE and Wavelet in the flutter derivative identification has not been reported in other literatuers in China.