Study On Mechanical Properties Of Magnetorheological Elastomer And Its Isolation Bearing

In recent years,intelligent control technology based on intelligent materials has been paid more and more attention at home and abroad.Magnetorheological elastomer(MRE)materials have become one of the research hotspots because their stiffness can be controlled under the action of external magnetic field.However,its development and application in the field of vibration reduction and isolation in civil engineering are still in the preliminary stage.In view of this,starting from MRE materials,the effects of particle volume fraction,magnetic induction intensity and other factors on magneto-mechanical properties of isotropic and anisotropic MRE materials were studied by means of mesomechanics and establishing representative volume element(RVE)method.A MRE bearing for isolation was designed and analyzed from the aspects of material selection,magnetic circuit calculation,coil arrangement and magnetic induction intensity distribution of isolation bearing.The magneto-mechanical properties of the MRE are equivalent and then transported to the isolation bearing,and the shear properties of the isolation bearing under different magnetic induction intensities(current intensities)are studied from the shear strain,loading frequency and compressive stress.The specific content and research conclusions are as follows:(1)By the method of mesoscopic mechanics and establishing the RVE model,choosing the appropriate method in selecting matrix constitutive model and the particle,under the small strain,stress strain curve of the MRE with existing experimental results are very close,which can better reflect the MRE under different magnetic induction intensity of the change of the stress strain curve.On the basis of this RVE model,the effects of different particle content and magnetic induction intensity on the magneto-mechanical properties of isotropic and anisotropic MRE were studied.The results show that the shear modulus of both isotropic and anisotropic MRE increases with the increase of particle content.Under the same strain,the shear modulus of isotropic MRE has a greater rate of change,but the shear modulus of anisotropic MRE is larger than that of isotropic MRE.The shear modulus of isotropic and anisotropic MRE with the increase of the magnetic induction intensity,when the magnetic induction intensity is about 0.6 T,the increment of shear modulus decreases,and gradually MRE reach the saturation state,so the MRE work needs to be considered in the practical application of magnetic induction intensity range.(2)A MRE isolation(vibration)support was designed.With the MRE reaching "magnetic saturation" as the design objective,the software simulation of the MRE isolator(vibration)bearing was carried out on the basis of theoretical calculation,and the distribution of magnetic induction intensity in the isolator(vibration)bearing was evaluated.Results show that under the conditions of the same laminar MRE structure,the same coil turns and the same current intensity,the magnetic induction intensity generated by the coil external arrangement is about 60% higher than that of the coil end-arrangement when there is no lateral movement at the position of the MRE in the bearing center When the isolation bearing has shifted sideways,external coil type of arrangement of the magnetic induction intensity is 57.4%higher than the coil end housing arrangement.Thus it can be seen,coil external type arrangement can provide higher magnetic induction intensity for MRE,closed magnetic circuit design for isolation(vibration)bearing internal produce higher magnetic induction intensity.(3)The results of MRE magneto-mechanical properties were calculated by equivalent parameters,then the equivalent results applied to the external coil in the arrangement of the isolation(vibration)bearing,shear strain,loading frequency,compressive stress is studied for MRE isolation(vibration)bearing shear performance impact.The results show that with the increase of shear strain,loading frequency and compressive stress,the horizontal equivalent stiffness of MRE bearing increases to varying degrees,but the change of magnetic induction intensity(current intensity)has a greater effect on the horizontal equivalent stiffness of the bearing.