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Critical speed

About: Critical speed is a research topic. Over the lifetime, 2764 publications have been published within this topic receiving 31365 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, the effect of yaw damper with its series stiffness value on the stability and bifurcation type of the railway bogie was analyzed. And the symbolic expression associated with yawdamper and its series stiffness to determine bifurlcation type at the critical speed was obtained by the method of Normal Form.
Abstract: Yaw damper, widely employed in high-speed railway vehicles, has played an important role in improving the hunting stability. This paper mainly makes a comprehensive analysis on the effect of yaw damper with its series stiffness value on the stability and bifurcation type of the railway bogie. With the prerequisite of the linear critical speed calculated by mathematical method, Center Manifold Theorem is adopted to reduce the dimension of the model to a planar dynamical system. And the symbolic expression associated with yaw damper and its series stiffness to determine bifurcation type at the critical speed is obtained by the method of Normal Form. As a result, the influence of the variation tendency of the yaw damper and series stiffness on the bifurcation type of the bogie is given qualitatively in contrast to different couples. Finally, numerical analysis of corresponding bifurcation diagrams is given to verify the accuracy of the conclusion.

9 citations

Journal ArticleDOI
TL;DR: Based on the active stiffness change theory, exploiting shape memory alloys' unique characteristic, an intelligent support system is designed for passing through high-speed aeroengine rotors critical speed in this paper.
Abstract: Based on the active stiffness change theory, exploiting shape memory alloys' unique characteristic, an intelligent support system is designed for passing through high-speed aeroengine rotors critical speed in this paper. Details of its operating principle is also introduced. Experimental results give an ideal demonstration of the theory. It has been ascertained that the intelligent support system is applicable for controlling the vibrations of high-speed aeroengine at the critical speeds.

9 citations

Journal ArticleDOI
TL;DR: In this paper, a flexible rotor supported by active magnetic bearing (AMB) is introduced, and the controller design for mode separation control is studied and the stability margin is evaluated according to ISO 14839-3.
Abstract: Reducing the weight of industrial rotational machinery equipped with Active Magnetic Bearings (AMBs) has been shown to achieve efficient hydraulic performance at high speed rotation. It also improves space efficiency and gives cost reductions. One of our solutions for increasing rotational speed is to experimentally demonstrate the passing of the 3rd bending critical speed. In this paper, a flexible rotor supported by AMBs is introduced. The controller design for mode separation control is studied and the stability margin is evaluated according to ISO 14839-3. After checking the stability, we successfully perform the rotation test to pass a total of 5 critical speeds, i.e., 2 rigid modes and 3 bending modes, by using a modal balancing technique. This paper proves that stability and balancing are key technologies for achieving high-speed rotation.

9 citations

Book ChapterDOI
01 Jan 2011
TL;DR: In this paper, a critical speed model for the multi-disk rotor of the rotor-bearing system of the grinder spindle was established based on the transfer-matrix method and taking into consideration the gyroscopic couple, the shear, the variable cross-section and other influential factors.
Abstract: Based on the transfer-matrix method and taking into consideration the gyroscopic couple, the shear, the variable cross-section and other influential factors, a critical speed model was established for the multi-disk rotor of the rotor-bearing system of the grinder spindle. The critical speeds of first three orders, the modes of variation and other dynamic characteristic parameters of the grinder spindle were numerical investigated and calculated. The influences of the axial pre-tightening force of the bearing, the span of the fulcrum bearing as well as the changes in the front and rear overhangs on the critical speed of the rotor-bearing system on the grinder spindle and their pattern of changes were analyzed. The results showed that the working speed of the spindle system is much lower than the primary critical speed and can therefore stay away the resonance range effectively. Furthermore, the span of the fulcrum bearing and the overhang had significant influences on the critical speed within a certain range, and the study provided the basis and guidance for the structural design and performance optimization of the grinder spindle.

9 citations

Patent
31 May 1995
TL;DR: In this article, a method and an installation in the roll operation of a paper machine is described, where the position of the critical speed ranges u KR, u 1/2 KR of the roll is adjusted whilst running the roll.
Abstract: The invention relates to a method and an installation in the roll operation of a paper machine. In order to prevent vibration of the roll in the critical speed ranges, the position of the critical speed ranges u KR, u 1/2KR of the roll is adjusted whilst the roll is running.

9 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
202343
2022120
202182
202092
2019102