Study on nonlinear dynamics of an elastic rotor-bearing-foundation system

In allusion, to the characteristics of a nonlinear rotor-bearing system, the nonlinear vibration of an elastic rotor-bearing-foundation system on the assumption of short-bearing model is formulated. And its characteristics studied in some parameter range based on rotor dynamics and nonlinear dynamics theory with the Poincare maps and numerical integration method in this paper. The nonlinear behavior of the system is analyzed along with the changing of the rotational speed and unbalance, and the result of calculation shows that may undergo, the period doubling, quasi-periodic and chaotic. motions. In some typical parameter regions the bifurcation diagrams., the time histories, the shaft centerline orbit, phase portrait the Poincare maps and the frequency spectrums of the system are acquired with numerical integral method. And the fractal dimension concept is used to determine whether the system is in a state of chaos motion. The analysis result of this paper provides the theoretical reference for designing and safely operating of this system.