Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
DYNAMIC ANALYSIS OF A MULTI-SHAFT GEARED SYSTEM SUPPORTED BY HYDRODYNAMIC BEARINGS
Submission Author:
João Henrique dos Santos de Pontes , SP , Brazil
Co-Authors:
João Henrique dos Santos de Pontes, Gregory Bregion Daniel, Tiago Machado
Presenter: Gregory Bregion Daniel
doi://10.26678/ABCM.COBEM2023.COB2023-1422
Abstract
The growing need for clean energy production is encouraging several studies related to wind power generation in recent years. Wind turbine drivetrains consist of several components, including a low-speed shaft connected to the rotor blades, a gearbox, and a high-speed shaft connected to the electric generator. The finite element method is a widely used numerical technique for simulating complex systems in several aspects, including dynamic analysis. Vibrational behavior of these multi-shaft systems is mandatory for understanding vibrational response, establishing critical operating limits, and improving wind turbine design development. In this work, a model of multi-shaft geared system is developed using the finite element method to simulate dynamic response of a wind turbine-like multi-shaft system. Shafts are modeled using a Timoshenko beam element with 5 degrees of freedom per node, and connected by helicoidal gears that couple all degrees of freedom of the system, and introduce a time-varying gearing stiffness. To evaluate the influence of bearing effects on the rotating system’s dynamic response, different types of bearing are considered in the numerical simulations. The effects of hydrodynamic journal bearings are discussed in comparison to simpler rolling bearings model. The rotating system is analyzed both in the frequency and time domain. Modal analysis is performed to predict the system’s natural frequencies and obtain Campbell diagrams, presenting the critical speeds of the multi-shafts of the rotating system. Unbalance response, in the form of a Bode Diagram, is also performed in order to determine the vibration amplitudes at different operating conditions. Finally, time responses are obtained using Newmark’s time integration method and a Fast Fourier Transform (FFT) is used to decompose time vibration signals and reveal internal gearboxes frequencies and their typical harmonics, associated to tooth meshing. The results obtained in this work provide important contributions related to the bearings effects on the dynamic response of a multi-shaft geared system, thus allowing to investigate possible improvements related to gearboxes, which are critical components for the performance of wind turbines.
Keywords
dynamic analysis, Hydrodynamic bearings, gearbox coupling, wind turbines
