Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
Stress State for Rotating Machine
Submission Author:
Clodoaldo Chagas , SP
Co-Authors:
Clodoaldo Chagas, Marcos Albuquerque, ROBSON PEDERIVA
Presenter: Clodoaldo Chagas
doi://10.26678/ABCM.COBEM2019.COB2019-1433
Abstract
The rotating machines are subjected to unbalanced rotors thus the shaft are dynamic loaded. The orbit of the geometric center of a cylindrical shaft differ as function of the angular velocity of this shaft. The stress state of a point on the surface of the shaft suffer alternation which is different from the behavior of a shaft with constant static load which is usually a sine wave. In Laval rotors the unbalanced mass excites the system in forward direction changing the orbit of the shaft center from an elliptical shape to a line near to the first natural frequency. The present work intent to model this phenomena and to create a stress state and frequency operation relationship in a Laval rotor using rotor dynamics theory applied for a rigid bearings model. The expected response for stress state is constant for low angular velocity when the orbit of the shaft are practically circular. At under critical angular velocity the shaft orbit tend to a line which cause an alternated stress state with average value different from zero. The response is not a perfect sine wave but is periodic and related to a complete loop of the shaft. This characteristic will be discussed.
Keywords
Rotor Dynamics, stress state, rotataing machinarey
