Identification for Bifurcation and Responses of Rub-impacting Rotor System

Abstract

The aim of this study is to investigate the dynamic responses of a rub-impacting rotor system. A response integration method is applied to analyze bifurcation and chaotic responses for the rub-impacting rotor system. This integration method numerically integrates the distance between state trajectory and the origin in the phase plane during a specific period. It provides a quantitative characterization of system responses and can replace the role of the traditional stroboscopic technique (Poincaré section method) to observe bifurcations and chaos of the rotor system with rub-impact. According to the result comparisons from the rub-impacting rotor system, it is inferred that during Poincaré section method being applied to be analyzed the system response periods, the sampling points on Poincaré section might be too close to cause disturbances to analyze if the system response is a high-order sub-harmonic vibration. Thus, the misjudgments for system response periods will be made. The simulation results, however, show that the high-order subharmonic and chaotic responses and their bifurcations can be observed effectively.

Effect of gravity-induced asymmetry on the nonlinear vibration of an overhung rotor

“…Ehrich [15] found that high speed rotors with bearing clearance exhibit very high orders of subharmonic vibration particularly for systems with low damping and extreme nonlinearity. The analysis of nonlinear motions with rub have also been classified using bifurcation plots, time series analysis, rotor orbits, Poincaré sections and the response spectra [16][17][18][19][20].…”

Rub‐Impact Detection in Rotor Systems with Pedestal Looseness Using a Nonlinearity Evaluation

“…e calculations for the procedure are given in (A.1) and (A.2) of Appendix A. e values for the parameters used in the nonlinearity measure and the simulations for equations (6), (11), and (21) are given in Appendix B. In order to maintain the accuracy of integration by fourth-order Runge-Kutta method, nondimensionalization is used to transform these systems to new systems using equation (20). Looseness clearances of the pedestal is used as a control parameter in order to perform a detailed investigation on the nonlinear dynamics of the bearing-rotor system, which uses the values 0 to 0.0035 m for simulations.…”

“…To overcome the difficulty in detecting the rubbing location, the model-based identification method is employed to provide quantitative information regarding the faults, including locations and severity. is method combines the dynamic characteristics and the dynamic model of the rotor systems with the signal processing techniques [19][20][21][22]. Despite a lot of research focusing on the analysis of the rotor systems with pedestal looseness [23][24][25][26][27][28], these methods have not been applied to identify the rub-impact in rotor systems with pedestal looseness.…”

Analytical Study of Nonlinear Vibration in a Rub-Impact Jeffcott Rotor

“…The full annular rub motions of a nonlinear Jeffcott rotor were investigated by Biao and Shu in [9], providing a basis for the parametric design of the rotor system with the help of the averaging method. Jeng et al [10] applied the response integration method to determine periodic motion in the response of the rub-impact rotor system, constructing a bifurcation diagram using Poincare section points.…”