各向同性磁流变橡胶材料的摩擦实验研究

分别从宏观和微观角度研究磁场对各向同性磁流变橡胶摩擦性能的影响.搭建了磁流变橡胶的摩擦实验平台,在外加磁场下进行滑动摩擦实验.实验结果表明,磁流变橡胶在轻载且低速条件下,摩擦系数随正压力增大呈减小趋势,而且磁场会使得磁流变橡胶表面的摩擦系数减小,且减小趋势随羰基铁粉体积比的增加呈现非线性变化,当羰基铁粉体积比为10％、正压力为0.25N、磁场强度为250 mT时,其摩擦系数变化最大,减小约25％.通过金相显微镜进一步观测施加磁场前后的磁流变橡胶表面,检测表明磁场使得羰基铁粉在磁流变橡胶表面产生聚集,从而使其表面材料属性及微结构发生变化,该变化是促使磁流变橡胶的摩擦性能发生改变的重要原因.

Experimental Study on the Friction of Isotropic Magnetorheological Elastomer Materials

The influence of magnetic field on tribological behavior of isotropic magnetorheological elastomer (MRE) was investigated from both macroscopic and microscopic view.Friction test-bed of MRE was built,and sliding friction experiment was carried out under an external magnetic field.The experimental results showed that the friction coefficient of MRE decreased with the increase of normal pressure under conditions of light load and low speed.The friction coefficient of.MRE surface decreased under magnetic field,and the decreasing trend presented a nonlinear change with the increase of volume fraction of carbonyl iron.The maximum reduction of friction coefficient was about 25％ when the volume fraction of carbonyl iron was 10％,the normal pressure was 0.25 N andthe magnetic field was 250 mT.Then the surface of MRE under magnetic field and nonmagnetic field were further observed by metallographic microscope.The test showed that the magnetic field caused the aggregation of carbonyl iron on the surface of MRE,which changed the material properties and micr'ostructure of the surface,and it was an important reason for the change of tribological behavior of MRE.