Research Random Variable Stiffness Coupling And Its Effect On The Rotor System Dynamics Performance

After linear and nonlinear rotor dynamics problems were studied deeply, rotor dynamics with random parameters is becoming an important subject that required to be reasearched. In order to study the rotor dynamics problems with random parameters by the method of experiment, it is necessary to research a test device that simulate the random parameters of rotor system.The paper is to develop a random variable stiffness coupling. Based on the characteristics that the elastic modulus of magneto rheological elastomer changes with the variation of the external magnetic field intensity, we developed a random variable stiffness coupling. And it is used to connected two test rotor of the Bently rotor experimental platform. Then we studied the effect of random variable stiffness coupling to the dynamics performance of rotor system by the method of experiment. The main research contents and results in this paper include the following aspects:1.Based on magnetorheological elastomer, the basic structure and working principle of random variable stiffness coupling was proposed. The work patterns of magnetorheological elastomer were analyzed, and the shear modulus calculation formulas of magnetorhe-ological elastomers were deduced. The stiffness characteristics of bellows coupling were analyzed. According to the mathematical model that has been established, we analyzed the influencing factors about the stiffness change.Theoretical analysis shows that the elastic modulus of magnetorheological elastomer and stiffness of corrugated pipe coupling also increase with the increase of the magnetic field strength.2.According to the principle that elastic modulus also increases with the increase of the magnetic field strength, we set up the test platform. Fisrt, we prepared the excellent magnetic rheological elastic body. Second, we designed and manufactured the corrugated pipe coupling with large deflection, and designed electromagnet structure device. Finally, based on magnetorheological elastomer, we researched a random variable stiffness coupling.Then it is used to connected two test rotor to set up the experimental research platform. It can be used for the experimental study on the dynamics performance of the rotor system.3.Based on the experiment platform, when electromagnetic structure was passed into the current 0-200 mA, we obtained the natural frequency of the rotor system, and fited the relationship between the natural frequency of the rotor system and the current by using the method of least squares, and found the linear region of the electromagnetic structure. When electromagnetic structure was passed into the random current that conformed to normal distribution, we obtained the natural frequency of rotor system. And the natural frequency of rotor system were statistically analyzed to obtain the mean value、variance and variation coefficient. The experimental results show that the natural frequency of the rotor system also accord with normal distribution with the random current conformed to normal distribution. In this test bench, we analyzed the effect of random variable stiffness coupling to the rotor system dynamic response by the method of experiment. The results show when the corrugated pipe coupling stiffness increases, the rotor system dynamic response decrease.