Research On The Composite Dynamic Model Of Magnetorheological Damper

Magnetorheological fluid(MRF)is a new intelligent engineering material.It consists of composed of high magnetoconductivity,low magnetic-lag nanomaterials and nonmagnetic liquids and surfactants.Magnetorheological fluid(MRF)has special rheological properties,which can transform from fluid to semi-solid by the effect of magnetic field,and the flowing deformation procedure is reversibility.Magnetorheological damper(MRD)has strong points of plain structure,fast respondence,large and steerable export damper force range,being able to adapt to a wide range of complex vibration conditions and insensitive to temperature.Therefore,it has been widely used in the field of semi-active vibration control of high-end mechanical equipment.However,the MRD working mechanism is more complex,which is affected by the combined action of magnetic hysteresis,viscous characteristics,multi field coupling effect(electric field,magnetic field,fluid field and solid field)and its control characteristics will change strongly under the external forced excitation.There are some deficiencies in the field of research on the MRD dynamic model and output damping force model at home and abroad,such as accuracy,complexity and so on.This paper takes the linear type of MRD as the research object.Considering the influence of various complex factors,the dynamic model and output damping force model of the MRD are established and evaluated by using the methods of parameter identification,sensitivity analysis and multi field coupling finite element analysis,and the mechanism of the influence factors is revealed on the vibration control effect.The main contents of this paper are as follows:(1)Combined with the linear MRD structural characteristics working principle and the Viscosity characteristics of MRF complex non Newtonian fluid,the theoretical results of the MRD mechanical model at home and abroad are summarized and analyzed.On this basis,Bingham model and polynomial model as the most applicable parametric models are taken as the object.According to the MRF hysteresis characteristics,the main parameters of the two models are identified,and their ability to predict the MRD output damping force is evaluated.Combining the advantages and disadvantages of the two models in predicting the output damping force,the MRD hybrid dynamic model is proposed,which combined the advantages of Bingham model and polynomial model.Finally,combined with the experimental data,the three models are compared to predict the MRD output damping force level.(2)The MRD output damping force is affected by the characteristics of hysteresis,viscosity and multi field coupling effect(electric field,magnetic field,fluid field and solid field).The output damping force model is taken as the research object,and the trajectory sensitivity analysis method is used to establish the MRD output damping force simulation model and MRD sensitivity analysis model of the single degree of freedom damping system.The contribution of seven parameters to the MRD output damping force is studied and sorted,such as structural parameters and working parameters,So that the influence of these parameters on the output damping force is revealed.(3)In view of the multi field coupling effect inside the MRD among electric field,magnetic field,fluid field and solid field under large external forced excitation or large change rate,based on the in-depth analysis of its coupling mechanism and research needs,the fluid-solid coupling and magnetic-fluid coupling with more obvious coupling effect are taken as the objects.ADINA finite element analysis software,which can realize direct analysis of multi field coupling,is used to explore the coupling,rheological process and mutual influence among internal flow fields.The multi-field coupling operator is constructed to modify the Bingham-polynomial compound dynamic model.The mechanism and influence of fluid structure coupling and magnetic fluid coupling on output damping force are studied.(4)Combined with the theory and simulation analysis,the linear MRD is used as the vibration control element to build a single degree of freedom vibration reduction system.The experimental research on the verification of the MRD mathematical model is carried out,including the parameter identification test based on sinusoidal forced excitation load.The accuracy of the research work is verified by the MRD dynamic model evaluation test considering the coupling effect of electric magnetic fluid solid multi field.