电流变液的发展现状

电流变液自1947年被Winslow发现以来,因其能快速、可逆地实现液一固相转变,并具有响应快（毫秒级）、连续可调、能耗低等优良特性,越来越为有关工程技术人员所关注。研究表明,电流变液在工程机械、液压系统、航空航天、机器人等众多领域具有广泛的应用前景。本文回顾了电流变液的发展和国内外的研究现状,阐述了电流变液的特点、组成、相关参数、理论模型及应用和优缺点,详细论述了产生电流变的机理、设计制造高性能电流变液的方法,并在此基础上提出了一些笔者对介电模型和电导模型的观点。     

Enhanced effect of dopant on polyaniline nanofiber based electrorheological response

As a potential candidate for electrorheological (ER) materials, polyaniline (PANI) nanofibers were synthesized via an interfacial polymerization route, because of their easy synthesis, high stability, controllable conductivity and good ER response. In this study, a new dopant, indole-2-carboxylic acid, was used to improve the ER performance. The synthesized PANI nanofibers were dispersed in silicone oil at 10 vol% and their rheological properties as an ER fluid were examined using a rotational rheometer under a variety of electric field strengths. In addition, their dielectric properties were studied using a LCR meter. The results showed that indole-2-carboxylic acid, which has high polarizability, enhanced the ER effect of PANI nanofibers, showing that polarizability is an important parameter affecting the ER behavior.     

复合颗粒电流变液的制备及其性能

制备了ＳｉＯ２／Ｐ（ＭＭＡ－ＭＡＡ）微囊复合颗粒电流变液,测试了该电流变液的力学性能和材料性能。结果指出：这种复合颗粒电流变液的稳定性有较大的提高;剪切强度随外加电场强度的增大而增大。     

电流变液力缓速器的研究

针对汽车辅助制动系统的需求,研制开发车用电流变液力缓速器.为此,研制开发了可控高压电源,配制了电流变液,在充分研究电流变液的粘度特性后,进行了电流变液力缓速器制动特性的研究.试验结果表明:同传统液力缓速器相比电流变液力缓速器具有结构简单,可控性好的特点;但与同体积的电涡流缓速器相比电流变液力缓速器的制动力矩只有其1/3左右,但损耗的电源功率只有其1/100左右.     

采用ER流体半主动座椅减振器的车辆平顺性模拟

介绍采用ER流体的筒式半主动座椅减振器车辆的平顺性模拟.建立具有针对系统不确定的内部鲁棒性的滑模控制器,通过控制电场来控制座椅的振动水平.模拟计算结果表明,采用半主动悬架时,在共振频率附近位移和加速度的传输率得到实质性的减小;当汽车驶过不平路面时,从半整车模型的位移和加速度的频率响应的整个频域段来看,采用ER流体半主动悬架汽车的性能得到了很大提高.特别是在1Hz以上频率段,位移和加速度传输率都得到了显著减小.表明通过采用ER流体半主动悬架能够很好地提高车辆的行使平顺性.     

Fabrication of ammonium persulfate coated silica microsphere via chemical grafting and its electrorheology

Silica/ammonium persulfate (APS) microspheres were fabricated by coating APS on the surface of ~2 μm sized silica particles and applied as a candidate for electrorheological (ER) materials. The morphologies of these particles were observed by SEM. Chemical compositions and structure of the particles were confirmed by EDS and FT-IR. Thermogravimetric analysis was used to examine the amount of APS coating on the silica particles. A 10 vol% ER fluid based on the fabricated particles was prepared by dispersing them into hydroxyl group-terminated silicone oil. Typical ER properties were obtained using a rotational rheometer under an applied electric field at a controlled shear rate test. These properties were also correlated with its dielectric spectra.     

Sol-Gel Preparation of Graphite/TiO2 Composite Particles and Their Electrorheological Effect

Graphite/TiO2 composite particles were obtained by sol-gel technique in this paper. The structure and characteristic of the composite particles are analyzed by XRD, SEM and TG-DTA. The electrorheological properties of the ER fluid containing the particles were measured by a Couette-type rheometer under shear rates of 1～136 s-1 and AC electric fields of 0～3 kV/mm. The experimental results show that the leaking current density of the ER fluid is higher than that of pure titanium dioxide particles dispersed in damping oil. The shear yield stress of the ER fluid increases with increasing electric field and exhibits a typical Bingham flow behavior. The suspension demonstrates an excellent ER performance (τ/τ0=1200) compared with conventional ER fluids (τ/τ0 ≤500). The sedimentation of the ER fluid is improved obviously due to the coating effect of the particles.     

电流变液添加剂的研究

从能量角度定量研究了添加剂对电流变液屈服应力的影响，提出了添加剂作用的极化模型。并用液晶材料作为添加剂进行实验，所得结果与极化模型理论相一致。     

电致流变流体──一种机敏材料

本文回顾了电致流变流体的发展状况，阐述了电致流变效应的影响因素及作用机理，指出了ＥＲ流体的使用前景。     

The influence of solid-phase concentration on the performance of electrorheological fluids in dynamic squeeze flow

The yield stress of electrorheological (ER) fluids increases by orders of magnitude when electric field is applied across them. In the absence of the field, ER fluids behave as Newtonian fluids. This paper is concerned with an experimental investigation to determine the rheological performance of ER fluids, consisting of a dielectric liquid carrier with a range of solid-phase concentration. The ER fluid was contained in a squeeze cell, which during motion subjects the fluid to both compressive and tensile loading. The results were analysed in terms of the capacity for the transmission of imposed forces across the fluid and showed a great dependence on the applied D.C voltage and the weight fraction of the dispersed solid-phase. In addition, the implications of the results to vibration control, where the ER fluid is employed in an engine mount, are discussed.     

电流变体智能材料在交变电场下的透光性能研究

电流变体作为智能材料作动器的一种,在外加电场的作用下,其材料性能会发生显著的变化。本文主要研究了二氧化硅／淀粉复合颗粒电流变体在交变电场作用下的透光性能的变化。对不同浓度的流体、不同外加电场强度,不同外加电场频率以及不同电极间距几种情况下电流以变体的透光性均进行了测试。     

带集中质量智能加肋板振动的自适应模糊控制

带有附加集中质量的加肋板振动控制问题在许多工程中都有重要意义.文章通过基于相互作用的带有附加集中质量和智能加肋梁的正交各向异性单向连续板振动问题的仿真力学模型,对加肋梁采用了ER电流变智能复合材料夹层梁的结构形式,并通过对ER流体施加电场,改变加肋梁结构的刚度和阻尼,从而调整带有附加集中质量加肋连续板的动力响应特性,对这一类结构进行了智能主动控制问题的仿真实验.在仿真试验数据的基础上应用自适应神经-模糊推理控制的方法,分别对激振频率和附加集中质量安装点的位置发生变化时,对带有附加集中质量的这种智能结构的振动问题进行了智能控制方法的仿真研究.仿真结果表明,自适应神经-模糊推理控制的方法能有效地抑制该类结构的振动.     

半主动控制电流变液压悬置隔振性能仿真研究

对半主动控制式电流变液压悬置的结构及工作原理进行了描述,考虑阻尼通道及电流变液的特性,建立了该悬置的动力学仿真模型.选择模糊控制作为控制算法,通过仿真计算研究了该悬置的隔振性能.利用ADAMS软件,建立了汽车动力总成悬置系统的六自由度动力学模型,对采用半主动控制式电流变液悬置的动力总成系统进行了仿真研究,并将其结果与采用被动悬置的动力总成系统的振动特性进行了比较分析.研究结果表明:施加控制之后,动力总成的振动将大为降低,这说明采用半主动控制式电流变液压悬置能很好地改善悬置的隔振性能.     

丙三醇/羧甲基淀粉/改性氧化钛复合颗粒的电流变性能

结合改进的水解法和溶胶-凝胶法,制备了丙三醇/羧甲基淀粉/改性纳米氧化钛复合颗粒,分析表明羧甲基淀粉和纳米氧化钛之间存在有相互作用;同时,介电测试表明此颗粒配制的电流变液的介电极化特性有很大改善.经流变学测试,此复合颗粒电流变液的动态剪切应力在颗粒质量分数为25%,剪切速率为100s-1,3kV/mm DC下为960Pa,剪切增幅比为35.同时,此电流变液的静态屈服应力在更高浓度,5kV/mm DC下可达到18kPa,比同等条件下改性氧化钛和CMS电流变液的静态屈服应力均有所提高.此外,这种电流变液还表现出较好的抗沉降性能.     

电流变流体的研究进展

电流变流体是近年来逐渐受人们重视的一种功能材料，本文介绍其国内、外发展过程及研究现状。     

Material characteristics of an ER fluid and its influence on damping forces of an ER damper Part I: material characteristics

This paper presents experimental results on material properties of an electro-rheological (ER) fluid subjected to temperature variations, mechanical and electrical fatigues. As a first step, an arabic gum-based ER fluid is made by choosing 30% of particle weight-concentration. Using the couette type of the electroviscometer, the field-dependent yield shear stress and current density of the ER fluid are measured by changing the operating temperature from −5°C to 85°C. A reciprocating cylinder mechanism is then manufactured to test mechanical endurance of the ER fluid. Under the specific excitation stroke and frequency, the variation of the yield shear stress is investigated with respect to the operating cycle up to one million cycles. In addition, following the construction of test mechanism for electrical endurance of the ER fluid, the yield shear stress and surface roughness of the electrode are evaluated as a function of the number of the electric-field cycle.     

ER流体特性及其研究现状

本文简要介绍了ER流体现象及其力学和电学性能,给出了描述ER流体行为的一般理论,提出了ER流体应用中目前存在的主要问题。     

表面改性纳米氧化钛的强电流变效应

以十二烷基硫酸钠（SDS）为表面改性剂,用溶胶凝胶方法制备出无定型改性纳米氧化钛颗粒,平均粒径为100nm．颗粒表面改性极大地提高了纳米氧化钛与硅油的浸润性和所配制电流变液的力学性能．颗粒浓度为3．0g／ml时,材料显示最佳的电流变效应,其挣态剪切应力值可达130kPa（4kV／mm直流电场）．与微米电流变液比较,纳米电流变液的抗沉降性能有较大的改善．颗粒的纳米粒径尺度、与基液良好的润湿性是形成改性纳米颗粒强电流变效应的主要原因．     

Effect of Microstructure on Electrorheological Property for Pure Particle Material

Pure titanium dioxide (TiO2) particle materials were prepared by hydrolyzing titanium tetrachloride (TiCl4). The microstructures of these materials were determined by X-ray diffraction (XRD), accelerated surface area and porosimetry apparatus (BET), and transmission electron microscopy (TEM). The TiO2 materials obtained by calcinations under different temperatures distinctly revealed different microstructures in crystal structure type, surface area, pore size, pore volume and grain size. The relationship between the microstructure of the TiO2 materials and their electrorheological (ER) activity was investigated. Anatase titania particles have better ER performance than rutile titania particles. Amorphous TiO2 materials display higher ER activity than the crystalline titania materials. A large pore volume can be more advantageous in improving the ER effect of a particle material.     

Effect of Microstructure on Electrorheological Property for Pure TiO2 Particle Material

Pure titanium dioxide （TiO2） particle materials were prepared by hydrolyzing titanium tetrachloride （TiCl4）. The microstructures of these materials were determined by X-ray diffraction （XRD）, accelerated surface area and porosimetry apparatus （BET）, and transmission electron microscopy （TEM）. The TiO2 materials obtained by calcinations under different temperatures distinctly revealed different microstructures in crystal structure type, surface area, pore size, pore volume and grain size. The relationship between the microstructure of the TiO2 materials and their electrorheological （ER） activity was investigated. Anatase titania particles have better ER performance than rutile titania particles. Amorphous TiO2 materials display higher ER activity than the crystalline titania materials. A large pore volume can be more advantageous in improving the ER effect of a particle material.