The Nonlinear Dynamics of a Rod-fastened Rotor

Abstract

Nonlinear bending stiffness of a rod-fastened rotor varies with applied loads posing a significant influence on the dynamic behavior. In this paper, the cubic model is adopted to perform an analysis of the nonlinear dynamic characteristics of a rod-fastend rotor: Firstly, the bending stiffness of a rod-fastened rotor involving two separate disks is obtained making use of the 3D FEM model. Then, a cubic stiffness model is applied to approximate the nonlinear stiffness and subsequently the corresponding governing equation can be derived. The harmonic balance method(HBM) as well as an iterative optimization method based on Broyden algorithm are adopted to yield the steady state response. Finally, influences of different parameters on rotor dynamics are further investigated in this manuscript. The results show that the cubic model can be used to demonstrate the amplitude jump behavior of the rod-fastened rotor and has an abundant nonlinear behavior. Furthermore, by adjusting the nonlinear system parameters, the position of the unstable region in the amplitude-frequency response curve can be changed, thereby effectively preventing the rotor system from operating in an unstable frequency region.

Nonlinear Analysis of Rod Fastened Rotor under Nonuniform Contact Stiffness

“…erefore, its dynamic characteristics are quite different from the integral rotor. We have the following literature on the research of rod fastened rotor [7][8][9][10][11][12]. Hu et al [7] considered the initial bending of the rotor when calculating the dynamics of the rod fastened rotor and systematically investigated the influence of rotational speed and initial bending on the dynamic response of the system.…”

“…Li et al [9] built a model of rod fastened rotor by the three-dimensional finite element method and investigated the nonlinear dynamic characteristics of the rotor by Floquet method. Based on the harmonic balance method, the influence of system parameters on the nonlinearity of the rod fastened rotor was proposed by Da et al [10]. Wang et al [11] analyzed the influence of machining errors such as mass eccentricity on the nonlinear characteristics of rotor-bearing system of rod by the three-dimensional finite element method and Floquet theory.…”