Simulation And Experiment Of Shear-mode MR-Rubber Dampers

Magnetorheological(MR)fluid has unique rheological effect,and good controllability.One-dimensional MR damper is currently applied in many engineering application.In the present work,one combined damper which is consisted of rubber damper and MR damper and can bear the shearing-load,is proposed.The performance of the damper has been tested in a testing machine.The experiments were carried out in a professional vibration test bench.The dynamics and spectral characteristics in the time domain and frequency domain of the MR damping system are analyzed using higher order spectrum analysis technology.The purpose is to introduce the MR technology into the engineering application with shear load.The main contents and conclusions of the thesis are listed as follows:1)The design of a shear-mode MR-rubber damper.The damper consists of MR and rubber parts.MR part is to provide controllable damping force whilst rubber part provides restoring force.The work gives the design methodology of the shear-mode MR-rubber damper as:for a rheological model based on the axis of symmetry,MR fluid constitutive relation is obtained using the Navier-Stokes equation to calculate the damping force and to analyze the effect of structure parameters on the performance of the MR-rubber damper.2)Magnetic circuit simulation and structure optimization.Simulation analysis of the magnetic circuit has been done based on ANSYS software,which proposed one new design scheme as:the piston and the rod are separated with adding front accumulator.Optimized structure can reduce the magnetic loop loss and can improve the control efficiency and performance of vibration absorption.Under different conditions of controlcurrent,shear rate,working fluid,working gap,the performance of the damper has been tested.The results indicate that the damper developed in this present work has excellent damping performance and characteristic and therefore,it could be recommended for engineering applications;3)Performance testing of MR-rubber dampers.Static and dynamic experiments were carried out by using SDS-100 electro-hydraulic servo testing machine to evaluate the performance of the damper.It was found that the design of the damper can be worked with rubber viscoelastic damping without controlling input;the resistance forces can be adjustable when MR was employed.4)Vibration reduction experiment on vibration test bed.A dynamics model of the experimental system was established.By changing the model parameters in different working states,the dynamic characteristics of the vibration system can be obtained in the time domain.In addition,the quantitative analysis of the effect of the control current on output performance were realized by using the variance analysis method.5)The high order spectrum characteristics of MR damping system was investigated by building an autoregressive time series model.The experimental results demonstrated thatautoregresive(AR)trispectrum not only shows the three frequency coupling characteristics but also it can descript equivalently the energy distribution system according to the size of the magnitude;however,its performance is not good enough.Two-dimensional slices,diagonal slice and the one-dimensional slice of the AR trispectrum could show clearly and intuitively the spectrum distribution and system coupling information.