Rayleigh Damping Coefficients Identification Using the Wavelet Transform on Two Stage Gear System

Abstract

Damping plays an important role in the simulation of the mechanical system. Various damping models are used such us non-viscous damping, coulomb damping, and hysteresis damping. For mathematical convenience, Rayleigh damping is usually used in a gear system to model damping. Rayleigh damping coefficients (RDCs) can be identified using the frequencies when the degree of freedom of the system is low. However, for complex systems, problems of selecting the frequencies of the RDCs are presented. The classical methods used only a constant damping ratio for all modes can underestimate the dynamic response. Continuous wavelet transforms (CWT) method is recently used to identify the modal parameters such as the natural frequencies and the damping ratios. This study presents initial research into the use of the CWT method to select the optimal frequencies of the Rayleigh damping formulation to identify RDCs. The RDCs are identified using the modes contributing to the dynamic response of the two-stage gear system. The modes that remarkably affect the dynamic responses are determined on the basis of the modes corresponding to the maximum values of the wavelet spectrum. The proposed method is validated using the simulated responses of a two-stage gear system and compared with the classical methods.