Design Theory And Test Of Broadband Vibration-isolated Magnetorheological Damper For Whole-spacecraft

Complex vibration loads are generated during the launch of the rocket,and the severe vibration environment poses a serious threat to satellite safety.The vibration mainly comes from the thrust of the rocket engine,gas pulsating pressure,noise excitation,etc.,which has the characteristics of broadband.At present,a rigid connection is usually adopted between the satellite and the rocket.This connection cannot prevent the satellite from the harsh vibration loads.If the effective vibration isolation mode is not adopted,not only the accuracy of the instrument and equipment carried on the satellite will be affected,but the satellite would run the risk of launch failure.Whole-spacecraft vibration isolation is an effective satellite vibration isolation technology.Thus,it has been a research hotspot on reducing satellite vibration in recent years.As an ideal semi-active vibration isolation device,magnetorheological damper has the advantage of fast outputting self-adaptive damping with the change of vibration.Thus,it has gradually become one of the important actuators in the field of whole-spacecraft vibration isolation.However,the mechanical model and dynamic characteristics of magnetorheological damper under broadband excitation are still to be studied.To this end,the present study perfects the mechanical model of the broadband vibration isolation magnetorheologiccal damper,and studied the design method,dynami performance test and virbration isolation test of broadband ibration isolation magnetorheological damper for the Whole-spacecraft.The results are of great significance for improving the vibration envviroment of the satellite during the launch phase.The main work of this paper is presented as follows:(1)The mechanical model of the broadband vibration isolation magnetorheological damper is established.Based on the constitutive relationship of the magnetorheological fluid,the damping force expression derived from the Bingham plastic model.In view of medium and high frequency excitation,considering the compressibility of liquid,inertia and bubble factors,the study establishes the mechanical model of magnetorheological damper under medium and high frequency excitation on the basis of quasistatic model.(2)Based on the established mechanical model,the magnetorheological damper is designed.3D model of magnetorheological damper was established by Solid Works software,and its working principle is analyzed.The finite element analysis software ANSYS was used to complete the design and analysis of the magnetic circuit of the magnetorheological damper,obtain the magnetic flux density at the working area of the piston,and to determine the structure size.And the mechanical properties of the damper are analyzed theoretically.(3)In order to study the dynamic mechanical properties of MR damper,the prototype of damper was processed,assembled and tested.Build a performance test platform based on MTS,the magnetorheological damper was tested under different working conditions.Then the test data and theoretical simulation results are compared.Energy dissipation characteristics,equivalent damping coefficient and equivalent stiffness of damper under different working conditions are analyzed.(4)In order to verify the effectiveness of the magnetorheological damper in the Whole-spacecraft vibration isolation,a test system for the Whole-spacecraft vibration isolation was built,and the Whole-spacecraft vibration isolation test based on the magnetorheological damper was carried out.The system test results show that adjusting the input current can change the transfer characteristics of the system and reduce the acceleration transmissibility at the resonance of the system to a certain extent.