Theory And Experiment Research Of The Damper Based On The Second Buoyance Principle Of Ferro Fluid

There exists a lot of micro vibration in the long straight objects of the spacecraft due to the influence of various factors during its run-time in the field of aerospace.Those vibrations have low frequency and small amplitude.They could do great damage to the normal operation of the spacecraft.In order to reduce these micro vibrations effectively,a new type of shock absorber based on the second order buoyancy principle of magnetic liquid was presented.The basic theory of magnetic fluid damping was analyzed.Experimental study on damping effect of magnetic fluid damper was carried out.The main work of this paper was as follows:1.The vibration control methods for the spacecraft were introduced.The merits and drawbacks of the typical passive damper in weightless environment were analyzed.At present,the limitation of spacecraft vibration reduction technology was put forward.2.The composition,basic characteristics and development history of magnetic liquid were introduced.The research status of vibration attenuation technology based on magnetic fluid was introduced.The basic principle and advantages of damping vibration of magnetic fluid were analyzed.3.The magnetization mechanism and buoyancy principle of magnetic fluid were analyzed.According to the basic law of fluid mechanics,the Bernoulli equation and the second order buoyancy expression of magnetic fluid were presented.4.The new structure of the magnetic liquid damping shock absorber was designed.Through the theoretical study and experimental research,the structural form of the damper was optimized.The structure of energy dissipation mass block was designed,and the material of the shock absorber shell,the material of permanent magnet and the type of magnetic fluid were selected.5.The viscous energy dissipation mechanism of the magnetic fluid damper was analyzed The viscous energy dissipation formula of the magnetic fluid damper during a vibration period was derived.6.Seven groups of magnetic fluid dampers were processed.The effects of the amount of magnetic fluid and the cone angle of shock absorber on the damping effect were studied.When the angle of the cone angle is 18 degrees,the damping effect of the damper was the best with15g magnetic liquid.Vibration decay time shortened by 90%.7.The damping effect of damping vibration absorber on different amplitude vibration was studied.When the vibration amplitude was between 3mm and 5mm,the damping effect was very good,and the damping effect is relatively poor when the amplitude were 1mm and 2mm.