非均匀磁场中磁流变液剪切应力实验与分析

为探究磁流变器件失效机理,用两块C型电磁铁耦合建立非均匀磁场。基于提拉法原理设计磁流变液剪切应力测量装置,得到非均匀磁场中剪切应力曲线。对比基于静态匀强磁场的圆筒剪切模型剪切应力理论曲线,发现虽然两者整体趋势一致,但同等磁场强度下两者剪切应力值存在不同程度差异,同时发现电磁铁气隙磁场也存在非均匀性。上述结论说明静态匀强磁场磁流变液剪切特性理论并不能直接应用到非均匀磁场剪切应力计算中,可能的原因包括铁磁颗粒体积分数的分布不均等,需要后续探索。

Test and analysis on shear stress of magnetorheological fluid under non-uniform magnetic field

To explore the failure mechanism of the magnetorheological device, non-uniform magnetic field was established with two C type electromagnet. Based on the principle of pulling method, measuring device was designed for shear stress of MRF, and shear stress curve was obtained under non-uniform magnetic field, almost in accordance with therotical one for cylinder shear modelin static magnetic field. That is to say, although both overall trend is consistent, the shear stress values are different under the same magnetic field intensity. It was also found that magnetic field in the electromagnet air gap also exist non uniformity. The above conclusion shows that the theory of magnetorheological shear stress based on the static magnetic field can not be directly applied to the calculation of the shear stress under non uniform magnetic field, likely thanks to unequal distribution of the volume fraction of the magnetic particles.