Dynamic characteristics analysis of a rotor–stator system under different rubbing forms

Abstract

Dynamic characteristics of a rotor rubbing with circular stator and four pin shape stators are studied based on contact dynamics theory. Based on finite element (FE) method, the rotor system attached with two disks and pin shape stators are simulated by Timoshenko beam. The circular stator is simulated by a lumped mass model, and the rotor and stator are connected by one or more point-point contact elements to establish the dynamic model of the rotor-stator coupling system. Assuming that the rubbing is caused by the sudden impact excitation and sudden unbalance excitation under two loading conditions (condition 1: in-phase unbalances of two disks at the first critical speed, condition 2: out-of-phase unbalances of two disks at the second critical speed), the system dynamic characteristics are analyzed by the time-domain waveform, rotor orbit, normal contact/rubbing force and stator acceleration. The results show that the rubbing caused by the sudden impact under the loading condition 2 will always exist and the rubbing will excite quasi-periodic motion of the rotor system; combination frequency components about the rotating frequency (1×) and the first lateral natural frequency of the rotor-stator coupling system (f n1 ) can be viewed as the most distinguishable characteristic. Full annular rubbing may appear due to the sudden unbalance excitation under the loading condition 1, the four-point rubbing can restrain the subsynchronous vibration and mainly excites odd multiple frequency components, such as 3×, 5×, etc.

Analysis of Nonlinear Dynamic Characteristics of a Mechanical-Electromagnetic Vibration System with Rubbing

“…Jacquet-Richardet et al [9] reviewed the numerical analysis and experimental analysis of the rotor-stator contact problem; Lu et al [10] established a rotor dynamics model considering radial rubbing, and analyzed the dynamic characteristics of frictionless, local friction, and full-cycle friction. Ma et al [11] studied the dynamic characteristics of rotor-stator rubbing based on contact dynamics theory; Xiang et al [12] established a nonlinear model to study the dynamic behaviors of a rotor-bearing system under the interaction of rubbing, crack, and oil film forces. Ma et al [13,14] studied the vibration response characteristics of dynamic and static structures rubbing.…”

Nonlinear Dynamics and Chaos of a Nonsmooth Rotor-Stator System

“…Concerning the rotor-stator behavior, some works are focused on the occurrence of full-rub, a phenomenon where the contact between rotor and stator is permanent and is maintained by the friction [14][15][16]. In general, the vast majority of the works considered two-degree-of-freedom (2DOF) models, related to rotor displacement, where the rotor is modeled as a Jeffcott rotor that may have contact with a stator flexibly mounted [10,11,13,[17][18][19][20][21][22].…”

Nonlinear analysis of a rub-impact rotor with random stiffness under random excitation

“…The different rubbing forms have significant influences on the dynamic responses of 1 rotor systems, such as fixed-point rubbing, 6 local rubbing, 7 and full annular rubbing. 8 And other activities 9,10 also illustrated the bifurcations and chaos of the rubimpact rotor in the deterministic system. There are many studies that focus on the research of random structures.…”