Identification of wear on hydrodynamic bearings through the anisotropy effect

Author(s)

Tiago Henrique Machado

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2014-08-22

Examining board members

Katia Lucchesi Cavalca Dedini; Robson Pederiva; Pablo Siqueira Meirelles; Thiago Gamboa Ritto; Luiz de Paula do Nascimento

• Advisor: Katia Lucchesi Cavalca Dedini

Abstract

The present work aims to identify the wear parameters of hydrodynamic bearings, one of the typical and inherent problems due to repeated use of rotating machineries, which can be accentuated in starts and stops or during the passage through the critical speed of the rotor. Thereby, a mathematical model capable of representing the wear in terms of its main parameters is proposed, which in the present work are the maximum depth and the angular position. The pressure distribution calculation and, consequently, the hydrodynamic forces generated by the oil film are numerically obtained by the finite volume method, adapted for situations where the oil film is discontinuous. In the rotor-bearing system modeling, the rotor model is represented by classic finite element method and the bearings are approximated by dynamic coefficients of stiffness and damping, in order to represent such inherent oil film effects. The identification of the parameters chosen to represent the wear is taken from the dynamic response, in directional coordinates, of the rotor-bearing system in the frequency domain. This identification is accomplished through a search method that aims to minimize an objective function which, in turn, compares the numerical response with the experimental response taken from an instrumented test rig. The results show that the wear model developed in this work is able to satisfactorily represent the behavior of a worn bearing, as well as the response of the rotating system in the presence of this type of failure. With respect to the identification process, the search method proves to be robust enough to identify the real wear parameters into the different configurations employed in the bearings mounted on the test rig (AU)

• FAPESP's process: 10/20241-4 - Identification of Wear on Hydrodynamic Bearings through the Effect of Anisotropy
• Grantee: Tiago Henrique Machado
• Support Opportunities: Scholarships in Brazil - Doctorate