Study On Magnetorheological Damper Of Hybrid Magnetic Field And Its Performance

Magneto-rheological damper(MRD)has been used roomily in the research of structural smart control because of their advantages,such as low energy using,rapid response speed and continuously adjustable force.Conventional Magneto-rheological damper is controlled by the current to achieve variable damping force.In the absence of current,the damping force is very small,and it increases as the curent increases.When the power is unable to supply or smart control system fails in large earthquake effect and breakdown happen to damper’s coil,however,the damping force is not controlled and the damping force is small in traditional Magneto-rheological damper.At the same time,stability of magneto-rheological damper will lead to obvious settlement of MR fluid.Therefore,it is of great significance and engineering application to study a new type of magnetorheological damper which can effectively improve the fault safety of magnetorheological damper and can effectively suppress the settlement of MR fluid.In this paper,the system theory and experimental study are carried out from several aspects of magnetorheological fluid,damper structure and its performance.First of all,starting from the core material of magnet-orheological fluid composed of magnet-orheological dampers,the MRF-P series of MR fluids were prepared by adjusting the surface properties of the magnetic particles and the thixotropic properties of the liquid particles,and were tested about the mechanical properties of different magnetic particle volume fraction of magnetorheological fluid and sedimentation stability of MR fluids.Then,from the perspective of micro force of magnetic particles,the force state of the magnetic particles in the magnetic field is analyzed theoretically.The influence of the magnetic field on the magnetic particles is simulated and analyzed by ANSYS.It is manifested from above tests that the sedimentation of MR fluid in external magnetic field has a positive effect;Finally,based on the analysis of the traditional magnetorheological damper,a hybrid magnetorheological dampers(HMRD)is designed and fabricated.The results show that when the current in the coil is zero,the HMRD can reach the medium damping force,and the damping force can be adjusted continuously and the adjustable coefficient is basically the same as the traditional MRD in power.