An Adjustable Elastic Support Structure for Vibration Suppression of Rotating Machinery

Abstract

The dynamic characteristic of a rotor-support system plays a crucial role in the operational efficiency and longevity of rotating machinery such as gas turbines. Traditional support structures with the fixed-parameter elastic stiffness have difficulties in adapting to the diverse and complex working conditions of flexible rotating machinery, particularly those that pass through multiple critical speeds. To address rotor resonance and enhance structural reliability, an innovative adjustable elastic support (AES) structure designed to improve the mechanical adaptability of rotors across various speed ranges is investigated in this paper. The AES structure is built upon the conventional squirrel cage elastic support by incorporating a stepper motor. By adjusting the rotation angle of the motor, the effective length of the cage bar can be modified, allowing real-time changes in the support state during rotor operation. This mechanism enables seamless transitions among multiple states: a constant stiffness elastic support, a separate state, or a variable stiffness dynamic absorber that modulates frequencies in real-time by altering the cage bar length. This dynamic capability effectively suppresses resonance peaks caused by mass imbalances. The design and implementation of the AES structure, along with a speed feedback-based adjustment scheme to accommodate the rotor's dynamic characteristics, are discussed. Experimental validation of a multisupport flexible rotor system demonstrates that a maximum vibration can be reduced up to 75%, highlighting its promising potential for engineering applications.