Design And Experimental Study On MRF Absorber Of Aircraft Landing Gear

Aircraft landing gear shock absorber is the important damping structure of aircraft,its damping performance will directly affect the performance of aircraft and the ride comfort of vehicle.In view of the deficiency of passive landing gear shock absorber now used in shock, there is need to study a new and intelligent control of shock absorber to improve the damping performance of the aircraft when taking off, landing and rollout.Magnetorheological fluid(MRF)is a kind of intelligent material which was widely used and has good performance.Its rheological properties is instantaneous reversible under the action of the magnetic field,and the shear yield strength has the stable corresponding relation with the magnetic induction intensity after the rheology.The MRF damper which is filled with MRF has accurate real-time control ability,continuous reversible change of damping force,low voltage and power consumption and simple structure and good stability endurance performance.Therefore,MRF damper is a kind of typical controllable fluid shock absorber,it has a broad application prospect in the semi-active control, which provide practical available way to improve the damping performance of planes, cars and bridge and so on.Based on the previous research of MRF damper,this paper designed a kind of MRF damper combined with the actual structure of aircraft landing gear shock absorber,which can not only realize annular clearance throttle but also action with the oil needle.Combined with the knowledge of fluid mechanics theory,MRF theory and MRF damper,this paper designed the structure of magnetic circuit,oil needle, gas chamber and so on according to the structure of MRF damper which have been confirmed.Finally, analysed and optimized the magnetic circuit through the APDL language of ANSYS,and optimized the oil needle section through the linear interpolation theory,which made the structure more reasonable.Through the dynamic and static test of the shock absorber,it showed that the shock absorber damping force can not only achieve current control but also can achieve stroke control, the damping force was still adjustable after the current control failed, and also have a good damping performance; The magnetic circuit efficiency of the shock absorber was very high, the adjustable scope of the damping force was big,and have good seal,inflatable structure not only simplified the structure but also has rapid response speed and reduced the manufacturing cost, these made the structure of the MRF damper was more close to the aircraft landing gear shock absorber structure,which provided certain reference to the application of MRF damper on the aircraft.In the last, summarized the research results and looked forward the prospect of the research on the MRF damper,and its application and pointed out some new study directions.