考虑磁性颗粒不均匀分布的磁流变液修正微观力学模型及试验验证

为了研究磁性颗粒在磁场作用下的不均匀分布对磁流变液力学性能的影响，通过卡方分布来模拟磁性颗粒的间距分布，对现有的磁流变液微观力学模型进行修正，并通过磁流变阻尼器的力学性能试验验证了模型的有效性。在磁流变液双链微观力学模型的基础上，修正相邻磁性颗粒的间距完全相等且不随磁感应强度而变化的假设，采用卡方分布来表征磁性颗粒间距的不均匀分布，并引入分布参数来描述磁性颗粒间距随磁感应强度的变化关系，推导了考虑磁性颗粒不均匀分布的磁流变液修正微观力学模型；基于修正的微观力学模型，分析了分布参数对磁流变液剪切屈服应力的影响；将该文提出的磁流变液修正微观力学模型带入到磁流变阻尼器的准静态模型中，可以得到不同电流下的阻尼器最大出力，并与磁流变阻尼器力学性能试验数据进行对比来验证所提模型的有效性。结果表明，考虑了磁性颗粒不均匀分布的磁流变液修正微观力学模型可以更加精确地预测磁流变液在不同磁感应强度下的剪切屈服应力，尤其是在低磁感应强度情况下可以改善现有微观力学模型放大了磁流变液剪切屈服应力的缺点。

A MODIFIED MICROMODEL FOR MAGNETORHEOLOGICAL FLUID CONSIDERING THE UNEVEN DISTRIBUTION OF MAGNETIC PARTICLES AND EXPERIMENTAL VERIFICATION

To study the influence of the uneven distribution of magnetic particles on the mechanical properties of magnetorheological (MR) fluid, the chi-square distribution is used to simulate the uneven distribution of magnetic particles under the action of magnetic field, and the existing micromodels of MR fluid is modified. The effectiveness of the model is verified by the performance test of MR dampers. Based on the double chain micromodel of MR fluid, the hypothesis that the distance between adjacent magnetic particles is completely equal and does not change with the magnetic induction intensity is corrected, and chi-square distribution is used to describe the uneven distribution of the distance between magnetic particles. A distribution parameter is introduced to quantitatively describe the relationship between the distance of magnetic particles and magnetic induction intensity, and a modified micromodel considering the uneven distribution of magnetic particles is proposed. Based on the proposed model, the influence of the distribution parameter on the yield shear stress of MR fluid is investigated. The MR fluid modified micromodel proposed in this paper is introduced into the quasi-static model of MR dampers, and the maximum output of the damper under different currents is obtained. The effectiveness of the proposed model is verified by comparing with the performance test data of the MR damper. The results show that the micromodel considering the uneven distribution of magnetic particles can describe the yield shear stress of MR fluid under different magnetic inductions more accurately, especially in the case of low magnetic induction intensity, which can solve the shortcomings of the existing micromodels that overestimate the yield shear stress of MR fluid.