Papers by Author: Chang Sheng Zhu

Abstract: Flywheels serve as kinetic energy storage and retrieval devices with the ability to deliver high output power at high rotational speeds as being one of the emerging energy storage technologies available today in various stages of development. This article analyzes the three-dimensional stress distribution of flywheel in Finite-element analysis. It is compared flywheel made of different material to meet the design of reasonable safety composite flywheel.

Abstract: To effectively control unbalanced vibration caused by grinding wheel mass unbalance, a new active control strategy for grinding wheel unbalanced vibration is proposed in the paper, the controllable electromagnetic force which is used to suppress vibration in control scheme originates from the principle of a bearingless motor having a radial magnetic force generation. First, induction electric spindle radial control force model and the force model which is exerted on grinding wheel are analyzed. And then, the dynamic model of induction-type flexural electric spindle-grinding wheel is modeled using finite element method. Finally, an active unbalanced vibration control system for electric spindle-grinding wheel is designed and simulated. The results show that the control scheme has significant effect on suppressing the unbalanced vibration of grinding wheel.

Abstract: The controllability of a magnetorheological(MR) fluid squeeze film damper under a sinusoidal magnetic field was experimentally studied on a flexible rotor. It is shown that the frequency of the excitation magnetic field has a great effect on the controllability of the MR fluid damper. As the magnetic field frequency increases, the controllability of the MR fluid damper significantly reduces. There is a maximum frequency of the magnetic field for a given magnetic field strength or a minimum strength of the magnetic field for a given magnetic field frequency to make the dynamic behavior of the MR damper be controllable. When the magnetic field frequency is over the maximum one or the magnetic field strength is less than the minimum one, the controllability of the MR fluid damper almost completely disappears and the dynamic behavior of the MR fluid damper with the sinusoidal magnetic field is the same as that without the magnetic field.

Abstract: The response time of a rotor system on a magnetorheological(MR) fluid squeeze film damper was measured experimentally. The effects of rotating speed, step voltage and rotor imbalance on the response time were dealt with. It is shown that the MR fluid damper rotor system is a second-order dynamic system. The rapid response time defined by the time taken for the vibration amplitude to rise (fall) from 10 % (or 90%) to 90 % (or 10%) of the vibration amplitude difference between the initial and final states is 0.05~0.7s in applying a step voltage and 0.01~1.225s in dropping a step voltage, respectively. It is impossible for the response time to be within a few milliseconds. The response time is determined not only by magnetic field strength, MR fluid specification, rotational speed, but operation mode of the power supply. There is a zero initial delay time at either applying or dropping the step voltage, which is caused by the magnetizing or de-magnetizing process.