巨电流变液对电场的动态响应和频率响应

The principle and properties of giant electrorheological(ER) fluids are essentially different from traditional ER fluids. The giant ER fluids have the important prospect in the technical applications because of its high shear stress. Dynamic response and frequency response of giant ER fluids in electric field are the basic properties of giant ER fluid and also determine the important indicator for their applications. However, those properties have not yet been well studied. Present proposal puts forward to systematically study on the dynamic response and frequency response of giant ER fluids in electric field as well as on the influences of various factors. Those factors include the viscosity of oil, volume fraction of particles, shear rate, field strength and temperature. Through the research we will acquire the regularity of the dynamic response and frequency dependence on electric field and understand the physical mechanism on the effects of different factors. Then experimental and physical basis for the practical applications of giant ER fluid can be provided, and also the methods for how measuring and determining these two properties of giant ER fluid can be afforded.

巨电流变液的原理和性质与传统电流变液有本质区别。巨电流变液的高剪切强度使其具有重要应用前景。在电场中的动态响应和频率响应是巨电流变液基本性质，也是确定其如何应用的重要指标。这些性质尚未很好研究。本申请提出对巨电流变液的对电场的动态响应和频率响应，以及各种因素的影响进行系统研究。这些因素包括液体粘滞性、颗粒体积分数、剪切速率、电场强度和环境温度。通过研究获得动态响应和频率响应变化规律，以及各种因素影响物理机制的认识。为巨电流变液的实际应用提供实验及物理依据，并为测量和判定巨电流变液这两种性能提供方法。

约20年前发展起来的巨电流变液，是在颗粒上添加极性分子进行制备，剪切强度可达数十到数百kPa，被认为是新一代电流变液，人们抱很大希望获得应用。然而，材料的实际应用需要满足各方面的要求，本项目即是对其性能进行深入全面研究，以判断此材料应用的前景。并在此基础上，改进和研发新材料，以实现电流变液可应用的目标。.1. 巨电流变液（PM-ER fluid）对外场波形、电场频率的响应研究：为了观测剪切强度如何随电场变化和响应，我们深入研究了不同频率三角波和方波电场中的剪切强度τ与电场强度E和频率f的响应行为，以及响应时间。结果表明，无论是在三角波还是在方波电场作用下，剪切强度都随电场频率的增加而减少。.2. 巨电流变液对电场响应时间、影响因素和变化规律研究：采用方波测量电流变液在电场作用下剪切强度随时间的变化曲线，测量采用快速采集和计数方法。分析了电场上升沿和下降沿的剪切强度响应时间的变化规律，得到了变化规律曲线，获得时间分辨的数据。.3. 研究成功第三代（分散金属型）电流变液：我们通过机械球磨将Al, Zn, Sn, Ni, Cu, 不锈钢，C等导电微粒分散在介电颗粒（二氧化钛）上，与绝缘油（如硅油和机械油等）混合制备成电流变液，均可具有较高的强度（可高达100kPa）。