Theoretical And Experimental Research On Two-dimensional Magnetic Fluid Dynamic Vibration Absorber

In spacecraft there are many long straight parts,such as solar arrays,antennas,and mechanical arms.Such parts are liable to generate low-frequency continuous vibration after being affected by external forces.In the space environment of weightlessness and vacuum,it is difficult for such vibrations to self-attenuation,continuous vibration will affect the normal operation of the spacecraft,and even threaten the health and life of astronauts.Magnetic fluid is a new type nano magnetic material.Its fluid properties will change with the change of the applied magnetic field,which makes it have important applications in many fields,and vibration control is one of its most important fields of applications.Magnetic fluid dynamic vibration absorber is a passive vibration controller.It's small size,simple structure,very sensitive to inertial force and it does not require external energy during work.It is very suitable for space and other scenes need strict requirements on device volume,quality and application methods,so it has important research significance.This paper proposes a two-dimensional magnetic fluid dynamic vibration absorber for planar vibration reduction based on the second-order buoyancy of magnetic fluid.The theoretical analysis,simulation,and experimental verification are used to study the dynamic vibration absorber.The work is as follows:(1)Firstly,the development of the levitation characteristics of magnetic fluid is combed,the first-order levitation characteristics and second-order levitation characteristics of magnetic fluid are introduced.Then,the application and development of magnetic fluid levitation characteristics in the field of vibration control are combed,including dampers and dynamic vibration absorbers.(2)Establish the vibration model of the two-dimensional magnetic fluid dynamic vibration absorber and give the equation of motion of the vibration damping system.introduce the magnetic field of the cylindrical permanent magnet required for the twodimensional magnetic fluid dynamic vibration absorber proposed in this paper,and introduce the Bernoulli equation and the boundary conditions of magnetic fluid.Derive the second-order buoyancy equation of the magnetic fluid.(3)By considering the complex vibrations in space,a two-dimensional magnetic fluid dynamic vibration absorber was designed and the size and material of each key component were confirmed.Use finite element simulation software to simulate the magnetic field of the dynamic vibration absorber,determine the structure of the energy-consuming mass block and the installation method of the permanent magnet,and determine the feasibility of the special-shaped roof through experiments and simulations.(4)The buoyancy of the energy-consuming mass block on the inner bottom surface of the body and the bottom surface of the roofs is calculated.Using the finite element simulation software,the buoyancy of the energy-consuming mass block in the twodimensional magnetic fluid dynamic vibration absorber filled with magnetic fluid is calculated,and the flying height of the energy-consuming mass block under different parameter conditions and the stiffness of the two-dimensional magnetic fluid dynamic vibration absorber is obtained.(5)The experimental method was used to obtain the relationship between the axial buoyancy on the energy-consuming mass block and the amount of magnetic fluid added,and a suitable method for adding magnetic fluid is obtained.Finally,further experiments and operation methods of buoyancy and vibration reduction are envisaged.There are 87 figures,14 tables,67 references in this thesis.