Abstract: The main objective of this research is to reveal the intrinsic principle of nonlinear vibration of gear system in virtual simulative environment. A nonlinear finite element model of a gear-rotor-bearing-box coupling system is developed by coupling transmission subsystem and structure subsystem of a large-scale burden marine gearbox with the support of bearing. By the simulation of its kinetic characteristic under the effect of internal and external excitations on the transmission subsystem, the time history plot, power spectrum density, phase trace and Poincare section are analyzed, and the maximum Lyapunov exponent is calculated. The results reveal that the system operates periodically and chaos phenomena do not occur under the current operating load. The further prediction of vibration signal shows that the prediction results by nonlinear dynamics methods and the results of finite element calculation coincide well, and indicates that the combination of the two methods can accurately predict the dynamic response of gears and reveal the inherent law of vibration signal, thus providing a scientific basis for the dynamic design of gear system.

Key words: Chaos identification, Coupling vibration, Forecasting, Marine gearbox, Nonlinear dynamics