Study On The Performance Of A Second Order Suspension Magnetic Liquid Damper

Flexible components such as solar panels and robotic arms are subject to complex vibrations during spacecraft operations.Such vibration is characterized by small amplitude,low frequency and long duration,and there is no air damping in the space environment.Therefore,continuous vibration will adversely affect the flexible manipulator and precision components on the spacecraft.Magnetic liquid is a new kind of intelligent material,it has excellent performance and a wide range of applications.The shock absorber with its core has a remarkable damping effect in the vibration control of spacecraft.Therefore,magnetic liquid shock absorber has broad application prospect and important research value in aerospace field.Based on the second-order suspension characteristics of magnetic liquid,a magnetic liquid damping damper is designed in this paper,which is studied from three aspects: theory,simulation and experiment.The main work is as follows:(1)The theoretical basis of magnetic liquid damper is introduced.The vibration model of the system is analyzed,and the factors affecting the performance of the shock absorber are discussed.Bernoulli equation and second order buoyancy equation of magnetic liquid are derived to calculate the magnetic field of cylindrical permanent magnet space.(2)The general structure of magnetic liquid damper is introduced.The material of magnet is selected and the magnetic induction contour lines of the two combinations of inertial mass blocks are compared by simulation.The material selection and structural design of the shell and end cover of the shock absorber are carried out,and the restoring force of the unilateral energy dissipating permanent magnet is simulated and analyzed to get the length of the connecting rod.The energy dissipation formula of shock absorber is derived,and the factors affecting the efficiency of vibration reduction are analyzed.(3)The effects of restoring force and magnetic field strength on magnetic liquid damper are simulated.The equivalent stiffness coefficients of the shock absorber under the change of the length of the connecting rod and the length of the shell are compared.The magnetic induction flow lines of two kinds of shell length shock absorbers are compared and the flux density at the inner wall of the shell is analyzed.(4)The damping performance of magnetic liquid damper with characteristic parameters is studied experimentally.It is found that the damping performance of the shock absorber is almost not affected by the initial amplitude.Compared with the vibration attenuation rate when the initial spacing between the inertial mass block and the recovery permanent magnet is 41mm-51 mm,the vibration attenuation rate is obviously better when the initial spacing is 53mm-63 mm.The damping performance under different shell inner diameter varies due to the amount of magnetic liquid.When the amount of magnetic liquid is less,the smaller the shell inner diameter of the shock absorber is,the higher the damping efficiency will be.However,when the amount of magnetic liquid is higher,the situation is reversed.Too much or too little magnetic liquid will lead to the performance of the damping shock absorber is not ideal.For the shock absorber with the shell length of 154 mm,the inner diameter of 34 mm and the connecting rod of 28 mm,the vibration attenuation rate can reach 96.598% when the amount of magnetic liquid is 18 ml.