Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
The influence of a crack in the dynamic behavior of a flexible disc
Submission Author:
Bruno Rende , MG
Co-Authors:
Izabela Batista da Silva, Tobias Morais, Aldemir Ap Cavalini Jr, Valder Steffen Jr, Bruno Rende
Presenter: Tobias Morais
doi://10.26678/ABCM.COBEM2017.COB17-2053
Abstract
The present work aims at evaluating the effects of crack on the dynamic behavior of a flexible rotating beam. The development, solution, and analysis of a system composed by a flexible rotor (mass-spring system) attached to four flexible blades is presented. The flexible blades are modeled as Euler-Bernoulli beams with tip masses at their ends. In this case, a linear beam model is associated with second order non-linear terms. The equations of motion of the entire rotor-blade system were obtained by applying the Newton-Euler-Jourdain method. The crack presence in the blade brings an additional flexibility, which is introduced in the blade model by using a torsional spring. The resulting blade stiffness is obtained through the equation of the beam elastic curve. The Newmark time integration method associated with the Newton-Raphson iteration procedure are used to solve the equations of motion. Two different scenarios were evaluated, considering both the healthy and cracked blade conditions. Finally, the dynamic responses of the rotor-blade system are shown in time and frequency domains, as well as the instability map.
Keywords
Rotating machine, flexible disc, transversal crack, frequency domain, waterfall diagram
