Rotor dynamics is a traditional research area that lacks no unsolved difficult problems. Also, rotor dynamics is a fundamental study to many rotary machines, which appear everywhere in our daily life ranging from jet engines to refrigerator compressors.
Every rotary machine consists of three basic elements: a rotary part (rotor), a stationary part (housing), and multiple bearings that connect the rotary and stationary parts. For many rotary machines, the rotors are cyclic symmetric, i.e., the rotors consist of N
Traditional rotor dynamics analyses focus on rotor-based formulations. Recently, rapid industrial developments demand more advanced vibration analyses that employ ground-base formulations for spinning cyclic symmetric rotors. This need manifests itself when the spinning rotor is coupled to a stationary housing via bearings. Some examples are explained as follows.
With increased material and energy costs, turbine engine industry seeks to reduce the weight and thus the rigidity of turbine engines. This results in significant vibration coupling the rotor, bearings and housing. With increased spin speed and various new applications (e.g., lift fans in Joint Strike Fighters for vertical takeoff and landing), gyroscopic effects must be accurately accounted for. With increased maintenance costs, industries seek to monitor ground-based rather than rotor-based machine response to avoid issues such as unbalance and poor reliability.
Mode shapes of a cyclic symmetric rotor
Experimental setup to measured ground-based response
Studying rotor dynamics using a ground-based formulation is by no means trivial. First, we developed a unified algorithm to predict ground-base response of spinning asymmetric rotors of arbitrary geometry. We have also extended this formulation to predict ground-base response of spinning cyclic symmetric rotors and furthermore to understand its physics. Again, our research in rotor dynamics encompasses mathematical modeling, numerical simulations, and experimental validation.
Our research in this area is traditionally funded by the National Science Foundation.
- C. W. Tseng, J. Y. Shen, Hyunchul Kim, and I. Y. Shen, 2005: A Unified Approach to Analyze Vibration of Axisymmetric Rotating Structures With Flexible Stationary Parts. ASME Journal of Vibration and Acoustics, Vol. 172, pp. 125-138.
- Hyunchul Kim and I. Y. Shen, 2009: Ground-Based Vibration Response of a Spinning Cyclic Symmetric Rotor with Gyroscopic and Centrifugal Softening Effects. ASME Journal of Vibration and Acoustics, Vol. 131, paper 021007, pp: 1-13.
- Hyunchul Kim, Nicholas T. K. Colonnese, and I. Y. Shen, 2009: Mode Evolution of Cyclic Symmetric Rotors Assembled to Flexible Bearings and Housing. ASME Journal of Vibration and Acoustics, pp. 051008, 1-9.
- W. C. Tai, and I. Y. Shen, 2013: Parametric Resonances of a Spinning Cyclic Symmetric Rotor Assembled to a Flexible Stationary Housing via Multiple Bearings. ASME Journal of Vibration and Acoustics, vol. 135, paper 051030.
- W. C. Tai, and I. Y. Shen, 2015: Ground-Based Response of a Spinning, Cyclic Symmetric Rotor Assembled to a Flexible Stationary Housing via Multiple Bearings. ASME Journal of Vibration and Acoustics, Vol. 137, pp. 041011-1 to 041011-12.
- W. C. Tai, and I. Y. Shen, 2015: Closed-Form Vibration Response of a Special Class of Spinning, Cyclic Symmetric Rotors-Bearing-Housing Systems. ASME Journal of Vibration and Acoustics, Vol. 137, pp. 061011-1 to 061011-12, doi: 10.1115/1.4031314.
- Y. F. Chen and I. Y. Shen, 2015: Mathematical Insights of Mode Localization in Nearly Cyclic Symmetric Rotors with Mistune, ASME Journal of Vibration and Acoustics, Vol. 137, pp. 041007-1 to 041007-13.