非线性复合介质电导的有效介质近似

在强外场作用下，复合介质的电输运性能服从非线性的本构关系。复合介质非线性电导率的计算相当复要，在线性复合介质的理论框架内，已发展了多种有效介质近似方法。利用有效介质近似，可以导出计算有效输运系数的简洁的解析公式。只要颗粒浓度在逾渗临界点以外以及颗粒和杂质的输运系数之比为有限的情况下，有效介质近似的计算都可以给出相当可靠的理论结果，因此，对于工程应用来说，有效介质近似是十分有的工具。本文在非线性复合

An effective medium approximation for conductivity of nonlinear composite

Transportation properties of composite under a strongly applied fie1d satisfy the nonlinear constitutive relationship. It is rather complicated to evaluate the conductivity of nonlinear composite. In the theory of linear composite, various methods have been developed under concept of effective medium approximation (EMA), which offers neat analytic formulae for evaluating effective transportation coefficients. Methods of EMA give reliable theoretical predictions, if particle concentration is beyond the percolation threshold and conductivity contrast is finite, Therefore, the EMA is a useful tool for technology applications. Based on perturbation expansion method for nonlinear composite, a new nonlinear EMA is proposed in this paper, which coincides well with generalized Landau formula at low particle concentration.