Design And Vibration Isolation Performance Research Of A Novel Magnetorheological Damper

In practical work,most of the failures of the vessel instrument and equipment are caused by vibration.With the increasing power of the vessel main engine,new requirements have been put forward to the vibration isolation device of the ship.The original passive vibration isolation can no longer adapt to various random vibration,but the new active vibration isolation is expensive.In recent years,the magnetorheological damper(MR damper)which has been widely paid attention to is one of the semi active vibration isolation device.This paper reviews the development of domestic and international structure of the magnetic damper.And designed a new cylinder axial winding type magneto rheological damper,which is suitable for wide frequency vibration isolation,to solve the problem of low magnetic field utilization and damping force with small adjustable multiple.The following aspects of the work is carried out in this paper.Firstly,aiming at the existing problems of the traditional hybrid MR damper,the cylinder axial winding MR damper that includes compound runners was designed by referring to the structure and magnetic circuit of the motor armature.Based on JMAG-Designer electromagnetic finite element software The new MR damper has been magnetically simulated.Simulation results show that the magnetic flux density of MRF in the new MR damper is greater than 0.5T,and the structure and magnetic circuit of the damper are reasonable.Secondly,Based on Bingham's constitutive model and fluid dynamics theory of MRF,a pseudo-static model of MRF between plates was established.Based on the structural characteristics of the new MRF damper,the damping force formula of the new MR damper was deduced and numerically calculated by Matlab.The results show that the maximum damping force of the new MR damper at 2.5 A is 2348 N,the design of the damper to meet performance requirements.Then,the dynamic performance of the new MR damper was tested by the electro-hydraulic servo fatigue testing machine.The experimental data of the maximum damping force of the MR damper at 2.5 A is 2645 N,adjustable damping multiple of 21.16.The damper Bouc-Wen model was built by Simulink,and based on genetic algorithm,the unknown parameters in the model are identified.The fitting data obtained from this model coincide with the experimental data,which can better describe the damping force speed curve of dampers.Finally,A new type of MR damper and compression spring parallel vibration isolation platform was built.The vibration isolation platform was operated by different frequency excitation,and the acceleration transmission rate under different frequencies and currents was measured.When the motor excitation frequency is 22 Hz,the acceleration transmissibility of the current at 2.5A is reduced by 6.1% than that of the current at 0A.The results show that the new MR damper can improve the isolation of the vibration isolation platform Vibration performance.In this paper,based on the performance test and vibration isolation experiment,a kind of axial magnetic-flux damper with axial magnetic field with high utilization ratio of magnetic field and high adjustable multiple of damping force is designed,which has important theoretical value and practical value for improving the technology of vibration isolation of ships significance.