Study On The Influencing Factors Of Response Time Of Magnetorheological Damper

Magnetorheological Damper(MRD)is a kind of vibration damper which changes the damping force by regulating the current.As a typical representative of semi-active vibration controller,MRD,with its excellent function,can be broadly applied in the field of impact isolation and vibration control.MRD has three important function indicators: maximum damping force,response time and regulative range.Among the three indicators,the response time is of greater importance,influencing the control frequency,application range and effect of MRD in a higher level.To search the response time of MRD,this paper combines magnetic field simulation calculation and test to carry out the study.The main study content is as follows:1.Analyzing the principle and structure of MRD.This paper has introduced the structure and principle of MRD as well as the working characteristics of magnetorheological fluid,introduced the working mode of magnetorheological fluid and established the structure of MRD that is based on the mechanical model of the existing MRD.2.Studying how the electromagnetic coil influences the response time.The ANSYS software is used to simulate the magnetic circuit structure of the MRD electromagnetic coil.By analyzing how the coil current,number and arrangement of coils influence the response time,the result shows the response time is reduced when the electromagnetic coil current increases.Compared with the response time of the single coil,the double coil with co-current costs more time while the double coil with counter current costs less time.And series-opposing coil costs less time too.3.Studying how the structure parameters of the damping channel influences the response time.This paper has analyzed the structural parameters such as channel gap,magnetic pole length,the surface shape of magnetic pole and yoke thickness.The result shows that with the increase of the channel gap and the length of the magnetic pole,the response time of the MRD decreases,but the yoke thickness slightly influences the response time.4.Studying how the material characteristics of magnetic circuit influence the response time.The magnetic parameters of 20 steel,45 steel,DT4 A and 40 Cr materials have been tested by soft magnetic DC measuring device,including initial permeability,maximum magnetic permeability,saturation magnetic induction,remanence and coercivity.Based on the magnetic parameters of the measured materials,this paper has analyzed the magnetic field simulation and obtained the response time and magnetic induction intensity of different materials.5.Studying the response time of MRD.This paper has tested how the damping force changes at different piston speeds and obtained the response time data.Before the test,an experimental scheme simulation has been designed.The influence trend obtained from test is consistent with that obtained from simulation.Based on the influencing factors of the response time obtained from the research,The magnetic circuit structure of the magnetorheological damper independently developed by the internship unit is improved.