Thermoplastic composites has attracted extensive attention in industrial process with excellent properties. As one of the most important parameters, electric conductivity is difficult to detect due to its inhomogeneity and anisotropy. In this paper, a novel method for measuring volume electric conductivity of composites based on eddy current loss has been introduced by using both experimental and numerical approaches. Initially, the eddy current loss and equivalent volume conductivity under different magnetic flux density are presented by analyzing voltage and current acquired in a designed air-gapless reactor under 500 Hz sinusoidal excitation with variety amplitudes. Then, to verify the measurement method and determine the influence of different materials on the eddy current loss, a 3-D electromagnetic model of the experimental devices is built and three cases with different materials are calculated. The parameters including eddy current loss and magnetic flux density are presented. The mechanism underlying the influence of different conductivity on the measuring model is analyzed according to the confidents and eddy current loss. Results show that the ratio of eddy current loss to the square of magnetic flux density is linear. The formula of equivalent volume conductivity needs to be revised by multiplying certain coefficients for high conductivity due to the eddy current effect on the detection coil. It is reasonable that magnetic flux density rang is set in 0.2∼0.8T during measurement.

中文翻译：

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基于涡流损耗的热塑性复合材料电导率研究


热塑性复合材料以其优异的性能在工业过程中受到广泛关注。电导率作为最重要的参数之一，由于其不均匀性和各向异性而难以检测。本文通过实验和数值方法介绍了一种基于涡流损耗测量复合材料体积电导率的新方法。首先，通过分析设计的无间隙电抗器在 500 Hz 不同幅度的正弦励磁下获得的电压和电流，得出不同磁通密度下的涡流损耗和等效体积电导率。然后，为了验证测量方法并确定不同材料对涡流损耗的影响，建立了实验装置的3D电磁模型并计算了三种不同材料的情况。给出了包括涡流损耗和磁通密度在内的参数。根据置信度和涡流损耗分析了不同电导率对测量模型影响的机理。结果表明，涡流损耗与磁通密度的平方之比呈线性关系。由于检测线圈上的涡流效应，需要修正等效体积电导率的公式，乘以一定的系数以获得高电导率。测量时磁通密度范围设置在0.2∼0.8T是合理的。