Dynamic Analysis of Rotating Systems Considering Uncertainties in the Bearings' Parameters

Author(s)

Ramos, Douglas J. ; Ferraz, Adamo R. ; Daniel, Gregory B. ; Ritto, Thiago G. ; Cavalca, KL ; Weber, HI

• Document type: Journal article
• Source: PROCEEDINGS OF THE 10TH INTERNATIONAL CONFERENCE ON ROTOR DYNAMICS - IFTOMM, VOL. 4; v. 63, p. 15-pg., 2019-01-01.

Abstract

Industrial applications, like steam turbines and pumps, require an adequate rotor and bearing modeling to predict its dynamic behavior. The use of robust models allows simulating the dynamic condition in order to prevent critical operation and possible faults. In general, the dynamic analyses of rotating systems are performed with deterministic models, however, they do not take into account uncertainties that could affect the system response. Thus, uncertainties analysis related to the components that compose the rotating machines are important to better estimate the response and guarantee the adequate operational conditions of the rotor system. This paper aims to analyze the dynamic behavior of rotors considering journal bearing parametric uncertainties. The shaft is modeled with the Timoshenko beam and a computational model is constructed by means of the Finite Element Method (FEM), where the rotor is supported by short fluid film bearings (Orcvik model). Uncertainties in the bearings' parameters are taken into account. The probability theory is used for the uncertainty modeling, and Monte Carlo simulations are applied to approximate the statistics of the response. The analyses performed in this paper evaluate mainly the influence of uncertainties in the first natural frequency and the vibration orbit of the shaft inside the bearing. It has been observed that the response of the system, for instance, the first natural frequency and the rotor's orbit, might change due to uncertain bearing coefficients, and the radial clearance is the most influent parameter in the simulations delevoped. (AU)

• FAPESP's process: 15/20363-6 - Fault tolerant identification and control of rotating systems
• Grantee: Katia Lucchesi Cavalca Dedini
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/20975-4 - Effects of the cavitation in hydrodynamic bearings on the dynamic behavior of rotors
• Grantee: Douglas Jhon Ramos
• Support Opportunities: Scholarships in Brazil - Master