Theoretical And Experimental Research On Tuned Damping Vibration Attenuation Based On Magnetic Fluid

Under the influence of the external environment and some of their own work,long straight flexible structures,such as solar sailboards,antennas,and extension mechanisms on the spacecraft,will produce a vibration with low-frequency and small-amplitude.Due to no air damping in the space,vibrations are not easy to attenuate by themselves,which will involve a serious of impacts on the normal operation and safety of the spacecraft.With the emergence of new intelligent nano-materials,magnetic fluids are used in the field of vibration attenuation,especially in the aerospace field.Magnetic fuid dampers have the advantages of non-leakage in a weightless environment,simple structure,sensitive inertial force,and strong versatility.Therefore,this paper proposes a magnetic fluid tuned damper based on the principle of second-order buoyancy of magnetic fluid.The research of magnetic fluid tuned damper is carried out with theory,simulation and experiment.The main work of this paper is as follows:(1)The development and application of magnetic fluid is introduced in the field of vibration control.And the basic knowledge of magnetic fluid is also introduced.Based on the suspension characteristics and frequency modulation characteristics of the magnetic fluid,the vibration damping device is analyzed and studied.At the same time,the electromagnetic energy dissipation device is introduced in detail by using the magnetization characteristics of the magnetic fluid.(2)The basic theory of magnetic fluid tuned damper is studied.And the phenomenon that the permanent magnet can be suspended in the magnetic fluid,is explained with the help of the Bernoulli equation and second-order buoyancy equation of the magnetic fluid.The electromagnetic damping coefficient and the amount of dissipated vibration energy are calculated for the electromagnetic energy dissipation device.(3)The structural design and simulation analysis of the magnetic fluid tuned damper are conducted.A passive magnetic fluid tuned damper based on magnetic fluid second-order buoyancy is proposed,and some work is carried out to design and select structural parameters.A single-degree-of-freedom mechanical model of the damped free vibration of the magnetic fluid tuned damper is established.And its stiffness and damping coefficient are analyzed,and the structural scheme is studied by simulation and experiment.(4)The damping coefficient of the magnetic fluid tuned damper is experimentally studied.The changes of the damping ratio and the damping coefficient are studied by different influences,respectively,including the different magnetic fluid injection amount(0.7g,0.9g,1.1g,1.3g,1.5g,1.7g),the external fixed magnet angle position(90°,45°,0°),and coils turns(0-turns,200-turns,300-turns and 400-turns).The electromagnetic damping coefficient is calculated,and it is related to the viscous damping coefficient and the motion state of the inertial mass.(5)The damping performance of the magnetic fluid tuned damper on the main system is studied.A two-degree-of-freedom mechanical model with additional magnetic fluid tuned damper in the main system is established,and the impact of restoring force on the damping performance is studied through experiment.After installing a magnetic fluid tuned damper with a unilateral injection volume of 1.1g,0 turns,and 90°,the time for the main system to reach equilibrium is shortened to 1/8.The vibration attenuation of the main system is extremely significant.There are 64 pictures,5 tables,80 references in these dissertation.