THREE-DIMENSIONAL ANIMATION NONLINEAR SYSTEM MODAL IDENTIFICATION USING WAVELET TRANSFORM

Abstract

The single-degree-of-freedom and three-degree-of-freedom viscous damping systems are simulated based on the Morlet wavelet function transformation in an effort to study the wavelet transform and further promote the optimization of nonlinear system modal identification. In the meantime, the modal animation display technology is studied using the Visual Basic (VB) 6.0 software and Open GL three-dimensional graphics library. The research object is a thin plate member with five degrees of freedom. The research results are as follows. In the single-degree-of-freedom viscous damping system, the identification frequency is 11.545[Formula: see text]rad/s, and the damping ratio is 2.87%. The simulation result has a small gap with the set damping ratio, and the identification in the system is accurate and reliable. In the three-degree-of-freedom damping system, the recognition accuracy of the first-order wavelet coefficient model is higher. Besides, the recognition accuracy of the natural frequency in the second-order is better, and the damping ratio error value is 11.08%. In the third-order, the natural frequency and the damping ratio have a large error from the theory; the error values are 24.53% and 32.11%, respectively. In the meantime, VB 6.0 software and Open GL software can effectively identify the actual shape of the research object, showing a good application effect. The above results can provide scientific and effective reference materials for subsequent research on nonlinear system modal identification.