Theoretical And Experimental Study On A Novel Dynamic Vibration Absorber Based On Magnetic Fluid

With the characteristics of large span,light weight,low stiffness and weak structural damping,the solar panels,antennas and other flexible accessories of spacecraft are prone to structural vibration under small disturbances,and are difficult to get the attenuation in the space environment,thus resulting into great influence on the working performance and safety of spacecraft.Magnetic fluid is a new kind of nano-functional material,which has vital applications in the field of vibration control.Dynamic vibration absorber based on magnetic fluid has the advantages of high sensitivity to inertia force,no power consumption,simple structure,small volume and long service life,so it is suitable to control the vibration with low frequency and small amplitude of solar panels and antennas in the spacecraft technology.In this paper,a novel dynamic vibration absorber based on the first kind levitation of magnetic fluid is proposed,of which theoretical and experimental studies are conducted.The main work is as follows:(1)The development and applications of magnetic fluid in the field of vibration control are reviewed.According to the vibration control methods,the magnetic fluid damping devices including dampers,vibration isolators,and dynamic vibration absorbers are analyzed.Additionally,the recent progress of vibration energy harvesters based on magnetic fluid is briefly provided.(2)Basic theories of magnetic fluid dynamic vibration absorber are studied.The motion equation,Bernoulli equation,the first kind levitation and the second kind levitation of magnetic fluid are introduced,and levitation equations of magnetic fluid are deduced.Moreover,the energy dissipation principles and the vibration model of magnetic fluid dynamic vibration absorber are researched.(3)The design and simulation analysis of magnetic fluid dynamic vibration absorber is conducted.A novel dynamic vibration absorber based on the first kind levitation of magnetic fluid is presented,of which the important parts are designed.The finite element method is used to simulate the magnetic field of the magnetic fluid dynamic vibration absorber and the feasibility of the scheme is verified.Schemes of magnetic fluid dynamic vibration absorber with and without the cover are determined through the preliminary experiment.(4)The experimental studies of magnetic fluid dynamic vibration absorbers are carried out.The effect of magnetic fluid addition on the damping performance of dynamic vibration absorbers,response of magnetic fluid dynamic vibration absorbers with different initial amplitudes,and different sizes of circular permanent magnets and masses on damping performance are studied.For dynamic vibration absorbers with and without the cover,the percentages of vibration attenuation are 94.34%and 90.59%,respectively,when the amounts of magnetic fluid are 16g and 21g.With appropriate amount of magnetic fluid,excellent damping performance of the dynamic vibration absorbers can be achieved under the initial amplitudes from 1mm to 5mm.