纳米SiO_2/LDPE复合介质的有限元数值仿真

纳米尺度下的界面结构是纳米复合材料的一个重要结构特征。建立了包含纳米颗粒、聚乙烯基质和界面层三相结构的复合介质仿真模型,在三维空间下对不同填充浓度的纳米SiO2/LDPE复合介质的极化电流和去极化电流进行了有限元仿真计算。为了验证这种三相模型的准确性,将仿真结果与实验结果进行了对比。结果表明,仿真电流和实验电流的整体变化趋势是一致的,尤其是在填充浓度比较低的情况下(小于1%wt),电流的起始幅值和随浓度变化的规律都和实验结果比较一致。但是仿真电流的衰减速率普遍比实验结果要小,尤其是当填充浓度比较大时(大于2%wt),两者相差较大。因此用这种三相模型来进行纳米复合介质的仿真计算是可行的,但是还需要进一步的完善。

Finite Element Simultion of LDPE/SiO2 Nanocomposite

Interfaces,in nanometric dimension,are the most prominent feature in nanocomposites.A three-dimen-sional three-phase model intended to describe the current behaviors of LDPE/SiO2 nanocomposite under DC voltage was presented.The polarization current and depolarization current were simulated by finite element method based on this model.In order to verify the feasibility of this model,practical current in LDPE/SiO2 nanocomposites filled with different content of nano silica were measured,respectively.It is shown that the trends of simulsted currents and practical currents are the simular,especially under low doping concentration（below 1% wt in this article）.However,the eurrent decay rate of simulated results and experimental results has a little difference,especially under high do-ping concentration（above 2% wt in this articele）.Thus,this three-phase model is useful in calculating the current be-havior of nanocomposite,meanwhile it is not perfect and still needs to be improved.