Nonlinear characteristic investigation of magnetorheological damper-rotor system with local nonlinearity

Magnetorheological (MR) dampers show superior performance in reducing rotor vibra-tion, but their high nonlinearity will cause nonsynchronous response, resulting in fatigue and insta-bility of rotors. Herein, we are devoted to the investigation of the nonlinear characteristics of MR damper mounted on a flexible rotor. First, Reynolds equations with bilinear constitutive equations of MR fluid are employed to derive nonlinear oil film forces. Then, the Finite Element (FE) model of rotor system is developed, where the local nonlinear support forces produced by MR damper and its coupling effects with the rotor are considered. A hybrid numerical method is proposed to solve the nonlinear FE motion equations of the MR damper-rotor system. To validate the proposed model, a rotor test bench with two dual-coil MR dampers is constructed, upon which experimental studies on the dynamic characteristics of MR damper-rotor system are carried out. The effects of different system parameters, including rotational speed, excitation current and amount of unbal-ance, on nonlinear dynamic behaviors of MR damper-rotor system are evaluated. The results show that the system may appear chaos, jumping, and other complex nonlinear phenomena, and the level of the nonlinearity can be effectively alleviated by applying suitable excitation current and oil sup-ply pressure.(c) 2022 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Magnetorheological (MR) dampers have excellent performance in reducing rotor vibration, but their high nonlinearity can lead to nonsynchronous response, resulting in fatigue and instability of rotors. This study focuses on the nonlinear characteristics of MR dampers mounted on flexible rotors. A hybrid numerical method is proposed to solve the nonlinear motion equations of the MR damper-rotor system. Experimental studies are conducted to evaluate the effects of different system parameters on the nonlinear dynamic behaviors of the MR damper-rotor system. The results show that suitable excitation current and oil supply pressure can effectively alleviate the level of nonlinearity.