Modeling and Nonlinear Dynamics Analysis of a Flexible Rotating Machinery System

A flexible rotor bearings model supported by nonlinear oil film forces is presented, where gyroscopic effect, static unbalance and couple unbalance are all taken into consideration. The dynamic equations are solved using the Runge-Kutta method. Phase portraits, Poincaré maps, bifurcation diagram and the maximum Lyapunov exponents are employed to analyze the nonlinear dynamical behavior of the rotor system under different system parameters. The numerical results show that the system exhibits rich nonlinear dynamical behavior including periodic motions, period doubling motions and chaotic motions as the system parameters are varied and the main route that leads the system to chaos is period doubling bifurcation.