Modal interactions in a rotating flexible disc

Abstract

This article presents a dynamic investigation on the modal interactions in a rotating flexible disc. The governing equation of the rotating flexible disc is modelled by both considering the disc as a von Kármán plate and including the initial transverse runout of the disc. When the equation is discretized by Galerkin's method, non-diagonal elements of the stiffness matrix induced by the centrifugal force of the rotating disc, which represent the modal interactions, remain. Effects of the modal interactions on natural frequency and total deflection of the disc are investigated. The investigation shows that neglecting the modal interactions should cause evident error in the dynamic analysis of rotating flexible discs. The modal interaction results in the initial transverse runout of a given mode not only affects the deflection of the mode itself but also causes the deflection of other modes with different numbers of nodal circles and becomes stronger with an increase in the disc rotating speed and the number of nodal circles.