Abstract

Cover meter is widely used to monitor the reinforced structures, and the response of the cover meter probe coil is used to locate the rebar, evaluate the diameter and cover depth of the rebar embedded in concrete. In order to analyze and optimize the performance of the cover meter, the analytical solution to the response of the probe is of great importance. Based on the theory of the second order vector potential (SOVP), the integral solutions to the coil coefficient and the impedance change of the rectangular coil are achieved when the normal direction of the coil is perpendicular to the axis of the conductive cylinder. The theoretical and experimental results are in excellent agreement induced not only by nonmagnetic materials but also by magnetic materials. The impedance changes of the rectangular coil and the circular coil with same sectional area are compared theoretically, as a consequence, the rectangular coil can help to find the direction of the rebar embedded in concrete. The allowed frequency of the coil is also discussed. These integral solutions to the impedance change of the rectangular coil can help the cover meter designers to optimize the coil parameters and the exciting frequency conveniently.

中文翻译：

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垂直于导电圆柱的矩形线圈的阻抗变化研究

摘要

覆盖计广泛用于监测钢筋结构，覆盖计探针线圈的响应用于定位钢筋，评估埋入混凝土中的钢筋的直径和覆盖深度。为了分析和优化覆盖仪的性能，对探头响应的分析解决方案非常重要。基于二阶矢量电势（SOVP）的理论，当线圈的法线方向垂直于导电圆柱体的轴时，可以得出线圈系数和矩形线圈的阻抗变化的积分解。理论和实验结果不仅由非磁性材料引起，而且由磁性材料引起的也非常一致。从理论上比较了矩形线圈和圆形线圈的截面积相同的阻抗变化，因此矩形线圈可以帮助找到埋入混凝土中的钢筋的方向。还讨论了线圈的允许频率。这些对矩形线圈阻抗变化的整体解决方案可以帮助覆盖表设计人员方便地优化线圈参数和激励频率。