Theoretical Studies on the Inter-Force Enhancement of Core-Shell Particles Dispersed in an Electrorheological Fluid

本文係針對電流變液中具核殼結構之分散粒子，根據電磁理論建構數學模式，利用點偶極近似並求解拉普拉斯方程式以計算電位，探討構造與材料的選用以期獲得高性能之電流變分散粒子。由計算結果得知，當施以低頻外部電場時將由材料的導電率比主宰電流變的應答強度，而施以高頻外部電場時則將由材料的介電常數比主宰電流變的應答強度。在實心粒子對介質油的導電率比高於1或介電係數比高於1的情形下，不論是使用核心改質或施以外層披覆，選用比原材料更高介電係數或導電率的材料即可達到目的。其中以使用金屬材質最佳，但需注意勿使整體導電率過高。本文採用的簡單模型來解釋已有實驗結果，針對顆粒改質對應力之提升建立材料選擇之準則，亦可提供製備電流變液核殼結構分散粒子之參考。

關鍵字

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並列摘要

The goal of this paper is to offer criteria for the material determination of core-shell structural particles in order to enhance the electrorheological effects obtainable with suitable combinations. Based on electrical and magnetic theories, the core-shell structure is investigated using the point-dipole approximation method to produce an electrical potential solution that satisfies the Laplace equation. A better structural combination is determined based on the mathematical results. The results show that the conductivity ratio dominates the ER response when the external field frequency is low. Conversely, the ER response is dominated by the dielectric ratio when the external field frequency is high. We choose a material with higher conductivity for the solid particle core or for a structured particle core-shell skin as long as the conductivity ratio or the dielectric ratio of the solid particle to the oil medium is greater than one. The best material choice is a metal when the overall conductivity of the fluid is not very high. This study used a simple model that explained all of the experimental results, which are presented here as a reference for dispersed particle fabrication in an electrorheological fluid.

並列關鍵字

Electrorheological fluid ； Dispersed Particle ； Core-shell structure ； Yield stress ； Dielectric constant

國際替代計量

Theoretical Studies on the Inter-Force Enhancement of Core-Shell Particles Dispersed in an Electrorheological Fluid

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