With the increasing need for the high-end turbomachinery, an accurate prediction for mode damping is urgently needed to ensure the machinery stably operates under the operation condition, and the accurate and reliable prediction and identification of bearing dynamic performance parameters are the prerequisites. The magnetic bearing as the actuator is used to apply excitation force on the flexible rotor system, and the response vibration is measured to accurately identify the parameters of bearings. The rotor-bearing system is transformed to a closed-loop control system in which the rotor shaft and bearings are taken as controlled plant and controller respectively; thus, the identification of bearing parameters is transferred to the problem of identifying the parameters of controller in a control system. This transformation solves the problem that the measured sensor was not located at the center of the bearing pad in traditional method, and the information from multi-section sensors can be used to increase the identification accuracy. A high accurate finite element model is developed for the model-based parameter identification, and the experiment is also carried out to verify the feasibility of this method. The accuracy of this method is verified by comparing the rotordynamic stability parameters (natural frequencies and log decrements) which are predicted by the estimated bearing stiffness and damping, and the measured values estimated by the sine-swept excitation. This method can provide convenient method to identify the bearing coefficients and can provide theoretical and technical basis for the stability design of high-end turbomachinery.
SHEN Bin
,
OUYANG Huabing
,
YAN Guangchao
,
LI Qihang
,
WANG Weimin
,
LIU Binbin
,
GAO Jinji
. Electromagnetic-excitation-based Identification Method for Identical Rotor-bearings System Parameters[J]. Journal of Mechanical Engineering, 2017
, 53(23)
: 1
-6
.
DOI: 10.3901/JME.2017.23.001
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