Nonlinear Dynamic Analysis of Rotor Rub-Impact System

Youfeng Zhu,Zibo Wang,Liang Wang,Hongyu Zang,Qiang Wang,Xinhua Liu

doi:10.1155/2019/4867364

Youfeng Zhu, Zibo Wang + Show 4 more

Open Access

https://doi.org/10.1155/2019/4867364

Copy DOI

Abstract

A dynamic model of a double-disk rub-impact rotor-bearing system with rubbing fault is established. The dynamic differential equation of the system is solved by combining the numerical integration method with MATLAB. And the influence of rotor speed, disc eccentricity, and stator stiffness on the response of the rotor-bearing system is analyzed. In the rotor system, the time history diagram, the axis locus diagram, the phase diagram, and the Poincaré section diagram in different rotational speeds are drawn. The characteristics of the periodic motion, quasiperiodic motion, and chaotic motion of the system in a given speed range are described in detail. The ways of the system entering and leaving chaos are revealed. The transformation and evolution process of the periodic motion, quasiperiodic motion, and chaotic motion are also analyzed. It shows that the rotor system enters chaos by the way of the period-doubling bifurcation. With the increase of the eccentricity, the quasi-periodicity evolution is chaotic. The quasiperiodic motion evolves into the periodic three motion phenomenon. And the increase of the stator stiffness will reduce the chaotic motion period.

Highlights

In the previous study of rotor dynamics, the single-disc rotor system is the main research object. e single disk rotor system is a real simplification of the actual rotor system
The trajectory of the axis is close to the limit cycle, and the Poincarecross section is a closed curve. e rotor system performs quasiperiodic motion
The dynamic model of the double-disc rotorbearing system with rubbing fault is established. e numerical integration method is combined with MATLAB to solve the dynamic differential equation of the system. e effects of the speed of the rotor, the disc eccentricity, and the stator stiffness on the response of the rotor-bearing system are analyzed. e following conclusions are obtained: (a) e rotor system moves periodically in the lowspeed range 200–767 rad/s

Summary

Introduction

In the previous study of rotor dynamics, the single-disc rotor system is the main research object. e single disk rotor system is a real simplification of the actual rotor system. Muszynska [2] proposed a simplified nonlinear oil film model and used this model to analyze the stability of the rotor-bearing system. Capone [3, 4] proposed a nonlinear oil film force model under the assumption of correcting short bearings. Is model is one of the commonly used oil film force models in dynamic analysis of rotor systems and has good accuracy and convergence. Jiang et al [5] simplified the rotor system of the centrifugal pump impeller and established the vibration model of the unbalanced impeller rotor with loose support failure under the condition of the introduction of nonlinear lateral fluid excitation force. E effects of the lateral fluid excitation force and the bearing mass on the nonlinear dynamic characteristics of the system were analyzed. In actual industrial production, there is often more than one rotor, and there may be a plurality of turntables or a plurality of rotor systems connected to each other by a coupling to form a multispan large rotor system

PN e φ x ω

Px Py

Conclusions