首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
不同介电常数悬浮颗粒的电流变液固态结构   总被引:1,自引:0,他引:1  
讨论了两种不同介电常数的固体颗粒不同配比时,对电流变液固态结构的影响。计算结果表明,颗粒的介电常数及配比变化时电流变液的固态结构没有变化,只影响其能量大小;而且发现在低介电常数颗粒的电流变液中加入少许高介电常数颗粒会引起体系能量的显著下降,从而增加了电流变液的稳定性和剪切应力。  相似文献   

2.
设计了结构单元连通的单一树枝状结构材料模型,通过把连通的树枝状结构材料置于高性能电流变液中,研究了电极间距、内嵌介质的介电常数以及电场强度等对浸入电流变液中树枝状结构左手材料透射峰的影响.实验结果表明,电极间距对样品的左手峰有重要的影响;在容器盒中充满电流变液之后样品的左手峰向低频方向移动;通过改变外加电场强度可以调节左手透射峰,最大调节范围可达140 MHz. 关键词: 连通树枝结构 电流变液 介电常数 左手峰  相似文献   

3.
王连胜  罗春荣  黄勇  赵晓鹏 《物理学报》2008,57(6):3571-3577
通过把负磁导率材料SRR阵列置于高性能电流变液中,研究了电极加载方式、电流变液浓度、电流变液类型以及电场强度等因素对浸入电流变液中的SRR阵列谐振频率的影响. 实验表明,电极加载方式对SRR阵列的磁响应有重要的影响;在容器盒中充满电流变液之后SRR阵列的谐振频率往低频发生了移动,并且可以通过改变外加电场强度来调节,最大的调节范围为130MHz. 数值计算结果表明SRR阵列的有效磁导率在谐振频率附近为负值,并且有效磁导率为负的频率范围也可以通过改变外加电场强度来调节. 关键词: 负磁导率材料 谐振频率 电流变液  相似文献   

4.
核壳型聚苯胺/钛酸钡的结构及其电流变性能   总被引:5,自引:0,他引:5  
用改进的溶胶 凝胶法制备了核壳型聚苯胺 /钛酸钡复合微粉 ,通过TEM及FT IR分析表征了其形貌及微观结构 ,用复合微粉与氯化石蜡油配制成无水电流变 (ER)液 ,研究其不同膜厚核壳粒子的电流变性能 .研究结果表明 ,聚苯胺 /钛酸钡复合粒子配置成的电流变液的电流变性能较纯聚苯胺的为强 ;钛酸钡的涂层厚度对复合粒子电流变性能有重要影响 ;并在d =2 0nm时获得最佳电流变性能 .  相似文献   

5.
电流变液的微波透射调控行为   总被引:2,自引:0,他引:2       下载免费PDF全文
依据外电场作用下电流变液结构由各向同性转变为各向异性及介电性能改变的实验事实,建立了微波穿透电流变液样品的理论模型,导出了微波透射率的基本表达形式.理论模拟显示:当电流变液的介电常量小于所处环境的介电常量时,透射率随电场的增加而增加;反之则减小.实验研究表明:电流变液的微波衰减(透射率)的变化可以通过电场来调控.分析认为在外加电场作用下,电流变液结构转变和介电性能的变化是导致微波透射率可调控的主要原因.  相似文献   

6.
电流变液的微波透射调控行为   总被引:3,自引:0,他引:3       下载免费PDF全文
依据外电场作用下电流变液结构由各向同性转变为各向异性及介电性能改变的实验事实,建立了微波穿透电流变液样品的理论模型,导出了微波透射率的基本表达形式.理论模拟显示:当电流变液的介电常量小于所处环境的介电常量时,透射率随电场的增加而增加;反之则减小.实验研究表明:电流变液的微波衰减(透射率)的变化可以通过电场来调控.分析认为在外加电场作用下,电流变液结构转变和介电性能的变化是导致微波透射率可调控的主要原因.  相似文献   

7.
赵晓鹏  渠长振 《光子学报》2000,29(3):213-215
液-液分散体系是一类重要的软物质,双液相电流变液属于液-液分散体系.在外加电场作用下,双液相电流变液内部结构可以发生改变,因而导致它的各种物理性能变化.本项工作研究了在电场与光场共同作用下的双液相电流变液的光学性能,了解其可调节透射率特征.  相似文献   

8.
磁流变液组分选择原则及其机理探讨   总被引:14,自引:0,他引:14  
从关流变液的流变机理及其性能指标出发,探讨了磁流变液组分母液、磁性颗粒、表面活性剂的选择原则及其对磁流变液性能的影响,及磁流变液的分散工艺;并在此基础上,研制成功了一种性能优良的磁流变液,其沉降稳定性较好,长时间(一个月左右)存放基本不沉降。  相似文献   

9.
为揭示高强度水下爆炸冲击载荷作用下金属夹芯结构的抗冲击性能,在实验室开展小尺寸水下爆炸加载技术对金属蜂窝夹芯结构性能影响的实验研究。基于实验结果,开展了全尺寸数值模拟金属蜂窝夹芯结构在水下冲击载荷作用下的动态响应和抗冲击性能研究。结果表明,数值模拟、实验和理论模型计算的结果具有良好的一致性。由于蜂窝芯材相对密度对夹芯结构能量耗散方式和载荷传递机制的影响,结构动态响应、失效模式以及抗冲击性能随着冲击强度的变化表现出较为明显的不同。通过抗冲击参数分析,建立了反映金属蜂窝夹芯结构抗冲击性能的结构横向变形、固支反力、透射脉冲和塑性能耗随冲击强度和芯材相对密度变化的结构-载荷-性能量化关系。  相似文献   

10.
电流变液中悬浮粒子形状与其固态结构之间的关系   总被引:1,自引:0,他引:1       下载免费PDF全文
采用近邻相互作用近似方法 ,计算了电流变液中悬浮粒子的形状对电流变液呈固态时基本结构的影响 .结果表明 :基本结构将随着悬浮粒子形状的变化而变化 ,特别是在扁椭球情况下 ,固态结构的相互作用能出现几个数量级的变化  相似文献   

11.
在合成并表征含苯甲酸甲氧基苯酯的侧链液晶聚硅氧烷高分子的基础上,制备了均相电流变(ER)液及其智能阻尼器.测试了ER液及其智能阻尼器在室温下的性能.结果表明,用含苯甲酸甲氧基苯酯的侧链液晶聚硅氧烷能组成在室温下表现出较强ER活性的均相ER液,它在外加电场E=2.2kV/mm,剪切速率为300s-1时,剪切应力达到1550Pa;增加E和振动频率,均相ER液智能阻尼器的阻尼力均增加,阻尼效果提高.  相似文献   

12.
用光学方法研究玻璃微珠电流变液颗粒间的相互作用   总被引:1,自引:0,他引:1  
运用一套适合研究颗粒间相互作用的双光镊系统,通过对粒聚集时间的测量,得出颗粒聚集时间和电场的平方成反比。这是第一次用电流变液颗粒在动态情况下直接验证电偶极子对间的相互作用。发展了一套使用高速CCD摄像机进行扩散波谱(DWS)测量的方法,首次实时测量具有颗粒结构的非各态历经体系的自相关函数,以研究电流变液机理,得到了玻璃微珠电流变液的结构响应时间和力和响应时间;测量了不同电场下体系相关函数的特征衰减时间随时间的变化。在不同电场下测量扩散系数可以反映出相互作用力与电场的平方成正比。  相似文献   

13.
The dynamic stability problems of a sandwich plate with a constraining layer and an electrorheological (ER) fluid core subjected to an axial dynamic force are investigated. The rectangular plate is covered in an ER fluid core and a constraining layer to improve the stability of the system. Effects of the natural frequencies, static buckling loads, and loss factors on the dynamic stability behavior of the sandwich plate are studied in the paper. Rheological property of an ER material, such as viscosity, plasticity, and elasticity may be changed when applying an electric field. The modal damper and the natural frequencies for the sandwich plate are calculated for various electric fields. When an electric field is applied, the damping of the system is more effective. In this study, finite element method and the harmonic balance method are used to calculate the instability regions of the sandwich plate. The ER fluid core is found to have a significant effect on the dynamic stability regions.  相似文献   

14.
We have investigated the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions byconsidering the particle shape effect. In particular, we consider coated oblate spheroidal particles and present a theoreticalstudy of ER based on the spectral representation theory. Analytic expressions for the characteristic frequency as wellas the dispersion strength can be obtained, thus simplifying the fitting of experimental data on oblate spheroidal cellsthat abound in the literature. From the theoretical analysis, we find that the cellshape, coating as well as materialparameters can change the ER spectrum. We demonstrate a good agreement between our theoretical predictions andexperimental data on human erthrocytes suspensions.  相似文献   

15.
The vibration transmissibility characteristics of a single-degree-of-freedom (SDOF) passive vibration isolation system with different nonlinear dampers are investigated in this paper. In one configuration, the damper is assumed to be linear and viscous, and is connected to the mass so that it is perpendicular to the spring (horizontal damper). The vibration is in the direction of the spring. The second configuration is one in which the damper is in parallel with the spring but the damping force is proportional to the cube of the relative velocity across the damper (cubic damping). Both configurations are studied for small amplitudes of excitation, when some analysis can be conducted based on analytical expressions, and for large amplitudes of excitation, where the analysis is based on numerical simulations. It is found that the two nonlinear systems can outperform the linear system when force transmissibility is considered. However, for displacement transmissibility, the system with the horizontal damper exhibits some desirable properties, but the system with cubic damping does not.  相似文献   

16.
Impact dampers have gained much research interest over the past decades that resulted in several analytical and experimental studies being conducted in that area. The main emphasis of such research was on developing and enhancing these popular passive control devices with an objective of decreasing the three parameters of contact forces, accelerations, and noise levels. To that end, the authors of this paper have developed a novel impact damper, called the Linear Particle Chain (LPC) impact damper, which mainly consists of a linear chain of spherical balls of varying sizes. The LPC impact damper was designed utilizing the kinetic energy of the primary system through placing, in the chain arrangement, a small-sized ball between each two large-sized balls. The concept of the LPC impact damper revolves around causing the small-sized ball to collide multiple times with the larger ones upon exciting the primary system. This action is believed to lead to the dissipation of part of the kinetic energy at each collision with the large balls.  相似文献   

17.
Magnetorheological (MR) damper is one of the more promising new devices for vibration control of structures. External energy required by the adjustable fluid damper is minuscule while speed of its response is in the order of milliseconds. The MR damper is a semi-active control device and has been characterized by a set of non-linear differential equations which represent a forward model of the MR damper, i.e., the model can generate a force to a given displacement and applied voltage.This paper presents an inverse model of the MR damper, i.e., the model can predict the required voltage so that the MR damper can produce the desired force for the requirement of vibration control of structures. The inverse model has been constructed by using a multi-layer perceptron optimal neural network and system identification, which are Gauss-Newton-based Levenberg-Marquardt training algorithm, optimal brain surgeon strategy and autoregressive with exogenous variables (ARX) model. Based on the data from numerical simulation of the MR damper, the trained optimal neural networks can accurately predict voltage. If the inverse model is used in a control system, the semi-active vibration control can be implemented easily by using the semi-active MR damper.  相似文献   

18.
考虑电流变液多粒子近程相互作用,利用等效平板电导模型,研究了电流变液流动过程相转变点的特性,并设计实验观察了电流变液中的这种相转变现象.研究结果表明,电流变液在一定压力梯度作用下发生流动,此时为双相流;当外加电场达到某一值时,电流变液中颗粒不流动,由固液双相流转变为液体单相流动,发生场控相转变,理论模拟结果与实验观察结果基本相符.阈值电场随外加压力梯度的增加而加大,随颗粒浓度的增加而减小. 关键词: 电流变液 颗粒流 相转变  相似文献   

19.
以流动模式(flow mode)多极板之电流变阀(electrorheological valve)进行避震器阻尼力特性的研究。由于电极板的大小直接影响到流体流动的剪力及避雷器的阻尼力,因此使用多极板型式来探讨避震器的特性。设计有1-5个流道之并联及1-3个流道之串联多极板电流变阀的电流变避震器,并使用自制的电流变液进行实验。由研究结果显示,流动式并联极板之电流变避震器,一个流道之阻尼力最大,流道极板增加则阻尼力反而下降,而流动式串联多极板之电流变避震器之阻尼力则随极板数递增,故需要高阻尼力之避震器较适合使用串联多极板型式。  相似文献   

20.
卢文  赵海兴  孟磊  胡枫 《物理学报》2021,(1):378-386
随着社会经济的快速发展,社会成员及群体之间的关系呈现出了更复杂、更多元化的特点.超网络作为一种描述复杂多元关系的网络,已在不同领域中得到了广泛的应用.服从泊松度分布的随机网络是研究复杂网络的开创性模型之一,而在现有的超网络研究中,基于ER随机图的超网络模型尚属空白.本文首先在基于超图的超网络结构中引入ER随机图理论,提出了一种ER随机超网络模型,对超网络中的节点超度分布进行了理论分析,并通过计算机仿真了在不同超边连接概率条件下的节点超度分布情况,结果表明节点超度分布服从泊松分布,符合随机网络特征并且与理论推导相一致.进一步,为更准确有效地描述现实生活中的多层、异质关系,本文构建了节点超度分布具有双峰特性,层间采用随机方式连接,层内分别为ER-ER,BA-BA和BA-ER三种不同类型的双层超网络模型,理论分析得到了三种双层超网络节点超度分布的解析表达式,三种双层超网络在仿真实验中的节点超度分布均具有双峰特性.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号