Nonlinear dynamic of the rod-fastening combined rotor system with rub-impact based on the Stribeck friction model

This paper aims to analyze the dynamic behavior of the rod -fastening combined rotor(RFCR) system in a rub -impact state and proposes a rod -fastening rotor dynamics model based on the Stribeck friction model. This model offers advantages such as generating frictional forces based on relative velocities and considering the coupling effects of rub -impact under complex excitations, providing greater flexibility in studying rotor systems. The Lagrange equation is utilized to deduce the RFCR formula, and the balance equation of the combined rotor is presented under friction, oil -film, and unbalanced conditions. This paper investigates the dynamic response of the RFCR system under rub -impact using the 4th -order Runge-Kutta method. The effects of parameter variations on the nonlinear dynamics of the combined rotor are systematically analyzed by means of bifurcation diagrams, motion trajectory, time domain waveform, frequency spectrum, and Poincare ' maps. The results show that the dynamic characteristics of the rotor system show a regular variation with the variation of the system parameters. Different forms of periodic motions, namely Periodic 1 motion (P1), Periodic 2 motion (P2), and Periodic 3 motion (P3) motions, along with quasi -periodic motions, are observed in response to varying system parameters. The results show that the higher the stator stiffness, the earlier the rotor enters the quasi -periodic speed. The velocity effect of friction reduces the speed range of the P3 motion of the rotor system and enhances the nonlinearity of the system. The magnitude and phase of the unbalance force change the frequency component of the system, which has a more substantial effect on the rotor system. These findings can help engineers and researchers in comprehending system behavior and designing more dependable and effective gas turbine rotor systems.