无磁场下磁流变液的温度特性及其幂律模型参数识别

磁流变液稳定工作的温度范围为-50~150℃,磁流变器件在工作过程中会发热,特别是连续高冲击工作情况下会严重发热,从而超出磁流变液稳定工作温度范围,影响磁流变器件工作的可靠性。针对美国Load公司的MRF132磁流变液,研究了不同温度下剪切应力与表观粘度随剪切速率的变化,并利用Origin软件分别对不同温度下磁流变液剪切速率与剪切应力进行幂律模型曲线拟合和参数识别。研究表明,幂率模型能够较好地描述零磁场下磁流变液的力学特性,不同温度下对于所有的流动指数n都满足n<1,表明不同温度下磁流变液具有剪切稀化特性,此特性符合粘度特性曲线,该工作对磁流变液温度特性的深入研究提供理论依据。

Study on the temperature characteristics of magneto rheological fluid under zero magnetic field and their parameter identificationof power law model

The stable working range of the magnetorheological fluid (MRF) is -50 ℃ to 150 ℃, for the magnetorheological device in the course of work will generate heat, especially under the condition of continuous high impact, beyond the stable working range of the MRF, which affect the stability of the magnetorheological device. In this paper, the relationship was researched between the shear stress and apparent viscosity at different temperature with shear rate of the MRF132 model development by Load Company in the United States. The relationship between shear stress and shear rate at different temperature are fitted by power law model and parameter identification by Origin software. The study results show that, the power law model can describe the mechanics of MRF in zero magnetic field well, all flow indices n meet n<1 at all different temperature, which indicated that MRF has shear thinning property at different temperatures, and this characteristic agrees with viscosity characteristic curve. This work provides a theoretical basis for the further study on the temperature characteristic of MRF.