On an ALE-Approach for Rotating Elastic Structures

Abstract

A new method for the description of rotating elastic structures is derived which is especially well suited for the description of coupled rotor-stator systems. The main idea is to eliminate the angle of the large rotational motion from the equations without neglecting the rotational velocity and the gyroscopic effects caused by it. This is done by describing the deformations in an intermediate frame. Assuming that the rotor is a cyclic structure, i.e. consisting of several identical segments which are arranged circularly, specific characteristics of the structural dynamics of a cyclic structure can be exploited. This leads to a transformation of the modal coordinates describing the deformations of the rotating body. The description is applied to a railway vehicle where the wheelsets are the rotors and the bogie frames and the car body is the stator. The wheelsets are modeled as elastic bodies. For this application, the description provides a simple structure of the equations of motion.