Evaluation of nonlinear responses and bifurcation of a rotor-bearing system mounted on moving platform

Abstract

The assessment of nonlinear phenomena with a focus on investigating the bifurcations and chaotic behaviour of an elastically induced flexible rotor-bearing system subjected to a harmonic ground motion has been studied. The higher-order Euler–Bernoulli deformation theorem has been adopted that governs the nonlinear dynamic characteristics of the rotating system. Nonlinear vibration analysis has been carried out to determine the critical speeds, i.e., Campbell diagram followed by demonstrating the inherent nonlinear signatures through the illustration of time history, Fourier spectrum and Poincare’s map upon varying the system design variables. The perturbation technique has been used to obtain the approximate nonlinear solutions from a set of polynomial algebraic equations under steady-state condition in various resonance cases. Further, stability analysis along with successive bifurcations of the solutions has been investigated. The present nonlinear model formulated based on Euler theory has been found to be capable enough to predict the correct value of critical speeds and dynamic responses in comparison with that of model developed based on Timoshenko theory. The present outcomes can offer immense practical importance for any application of the flexible rotor-bearing system when it performs high-speed operation.