Instabilities of an Asymmetric Rotor With Asymmetric Shaft Mounted on Symmetric Elastic Supports

Abstract

Instabilities of an asymmetric rotor with asymmetric shaft mounted on symmetric elastic supports are considered. The periodic coefficients which appear in the system equations are eliminated by transformation to a rotating coordinate system rotating at the constant angular speed of the rotor. The unstable speed regions are identified by studying the nature of the roots of the characteristic equation. The combined effects of the inertia and shaft asymmetry and the flexible supports are appreciated by representative numerical examples. The results are presented in three-dimensional diagrams to show how the asymmetry parameters affect the unstable speed regions for known values of support stiffness.