Effects of Bounded Uncertainties on the Dynamic Characteristics of an Overhung Rotor System with Rubbing Fault

Abstract

This paper investigated the nonlinear vibrations of an uncertain overhung rotor system with rub-impact fault. As the clearance of the rotor and stator is getting smaller, contact between them often occurs at high rotation speeds. Meanwhile, inherent uncertainties in the rubbing can be introduced for a variety of reasons, and they are typically restricted to small-sample variables. It is important to gain a robust understanding of the dynamics of such a system under non-probabilistic uncertainties. A non-intrusive uncertainty quantification scheme, coupled with the Runge-Kutta method, was used to study the effects of the rub-impact related interval uncertainties on the dynamical response individually and simultaneously, including the uncertainties in the contact stiffness, clearance, and friction coefficient. Moreover, the numerical validation of the developed analysis method was verified through comparisons with the scanning approach. The results obtained provide some guidance for investigating the uncertain dynamics of rubbing rotors and diagnosing the rub-impact fault under non-random uncertainty.

On post-resonance backward whirl in an overhung rotor with snubbing contact

“…They showed that relatively small uncertainties in system parameters can have significant effects on the dynamic behavior of rotors. This work was later extended to include the effects of rubbing [19].…”

A state-of-the-art review on uncertainty analysis of rotor systems

“…However, this process is rather complicated and involves several structures and disciplines, such as mechanics, friction and thermal effects. To predict the inherent variabilities in the rubbing process, works have been done to take the initial clearance, contact stiffness and friction coefficient uncertainties into consideration [77][78][79]. The bow fault represents the initial deformation of rotors caused by thermal effects or self-weight.…”

“…However, this simple model may limit the practical applications. Fu et al [79] extended the interval analysis to an overhung rotor system subject to rub-impact in which the clearance between rotor and stator, contact stiffness and friction coefficient were used as uncertain variables. However, it lacks exploitation of deeper nonlinear characteristics since time history responses can exhibit limited information.…”

Dynamic Modeling of the Dissipative Contact and Friction Forces of a Passive Biped-Walking Robot

“…Another interesting way to research dynamic analysis with friction would be on rotating machines with clearance. Fu et al [34] carried out a study of the nonlinear vibrations of an uncertain system with clearance and friction. Chao define the dynamical of the rotor and stator with three critical parameters involved in the impact between the rotor and case: the clearance, the contact stiffness and the friction coefficient.…”