非均匀动态复合场下磁流变液流变特性及传力机理研究

As the rheological properties model of magnetorheological fluid and the load-transferring model could not meet the needs of the actual working conditions of magnetorheological devices in traditional static uniform field. The actual working conditions were simulated and used non-uniform dynamic composite field. The rheological properties of magnetorheological fluid and the load- transferring mechanism had been studied in this project. The method combined theoretical analysis with experimental verification. Firstly, the project would make research on the temperature field and magnetic field which influence the process of magnetorheological fluid internal ion polarization from microcosmic perspective of influence and establishment of the theoretical model. Then the comprehensive testing system is developed in non-uniform dynamic composite field and conduct the magnetorheological fluid rheological properties experiment and load-transferring experiment. Finally, the mathematical model is optimized by experimental results. The project research contents are as follows: ①The internal ion polarization mechanism of magnetorheological fluid would be studied in the non-uniform dynamic composite field. ②The comprehensive test system of magnetorheological fluid rheological properties would be developed.③The model of magnetorheological fluid rheological properties and load-transferring would be established in non-uniform dynamic composite field. The establishment of the project with magnetorheological fluid rheological properties and load-transferring model in non-uniform dynamic composite field would break through the limitations of mathematical model in traditional static uniform field, even adapt to the complicated conditional requirement of magnetorheological device and guide the development and application magnetorheological technology better.

针对传统的静态均匀场磁流变液流变特性及传力机理不能满足磁流变器件实际工况需求的问题，使用非均匀动态复合场模拟实际工况，进行了磁流变液流变特性模型及传力模型的研究。运用理论分析与实验验证相结合的方法，首先从微观角度研究磁场、温度场变化对磁流变液内部离子极化过程的影响，建立理论模型，然后开发非均匀动态复合场下磁流变液流变特性综合测试系统，进行磁流变液流变特性及传力实验，再由实验结果优化数学模型。项目研究内容：①非均匀动态复合场下磁流变液内部离子极化机理研究；②磁流变液流变特性综合测试系统开发；③建立非均匀动态复合场下磁流变液流变特性数学模型及层间传力模型。项目建立的非均匀动态复合场下磁流变液流变特性模型及层间传力模型，突破了传统静态均匀场下数学模型的局限，将能够适应当前磁流变器件复杂的工况需求，有助于更好的指导磁流变技术的发展与应用。

为了准确的描述磁流变液在实际环境下的工作过程，本研究以非均匀动态复合场（磁场、温度场）模拟实际工况，研究了磁流变液在实际工况下的流变特性、内部结构及层间传力机理。研究分别以磁流变液圆筒型剪切模型和平板型剪切模型为基础，对磁流变液在非均匀复合场内的剪切应力输出及传力情况进行了研究。研究内容如下：（1）开发了圆筒型及平板型两套非均匀复合场下磁流变液性能测试装置；（2）对圆筒型剪切模型进行了有限元分析，得到了磁流变液圆筒型剪切模型及磁流变液剪切应力与温度、磁场之间的关系式，并通过反解磁流变液剪切应力与磁场、温度之间的关系式，得到外磁场对温度变化的补偿函数；（3）对平板型剪切模型建立了非均匀场下磁流变液离子极化模型；（4）将磁流变液单链内的铁磁颗粒等效为磁偶极子并对其受力分析，指出温度场仅改变磁偶极子间距，对相互作用力起次要作用。而磁场改变磁偶极子磁化强度等，对相互作用力其决定性作用的结论。（5）建立了剪切模式下磁流变液层间传力理论计算模型。（6） 设计了剪切模式下磁流变液层间传力特性实验装置。在磁场和温度场所组成的复合场的作用下测试了剪切模式下磁流变层间传力特性，建立了剪切模式下磁流变液层间传力特性曲线。发现在铁磁性颗粒达到磁化均匀的情况下，其剪切屈服应力的层间输出特性呈对称分布，其对称面是沿磁流变液所在空间高度方向上的中间平面，形成一个中间高且逐渐向两头降低的磁流变液剪切屈服应力转盘所在位置特性曲线。.在以上研究工作基础上，本研究得到了非均匀复合场下磁流变液的流变特性，层间传力机理；揭示了温度影响剪切应力的本质原因；根据磁场与温度场的耦合现象，提出了磁场补偿温度变化的恒剪切应力输出解决方案；认识到非均匀场下，各处的剪切应力不同；壁面滑移现象对磁流变液的传力影响较大。该研究成果对于磁流变器件失效机制诊断，新型器件开发，具有重要的指导、借鉴意义。