层叠导体脉冲涡流检测中探头瞬态响应的快速计算  

Fast Calculation of Probe's Transient Response to Pulsed Eddy-current for Inspection of Multi-layered Conductive Structures

作　　者：张玉华[1] 孙慧贤[1] 罗飞路[1] 

机构地区：[1]国防科学技术大学机电工程与自动化学院,湖南省长沙市410073

出　　处：《中国电机工程学报》2009年第36期129-134,共6页Proceedings of the CSEE

摘　　要：针对飞机多层金属结构中各类隐藏腐蚀导致的金属层减薄、层离间隙变化等问题,建立任意n层层叠导体结构脉冲涡流检测的电磁场理论模型,应用矢量磁势A推导得到了导体结构对线圈探头的反射系数,将之归纳为n个矩阵相乘的形式。进一步导出了同轴双线圈探头频域响应的积分表达式,并根据低频电磁场传播特性和偏微分方程理论,将二重广义积分转化为级数求和,采用快速傅里叶变换计算探头的瞬态响应,并与有限元时步法进行对比,验证理论推导的正确性,结果表明级数展开结合快速傅里叶变换是一种更快速有效的求解方法。To research metal thinning, interlayer gap variation caused by all kinds of hidden corrosion in aircraft multi-layered metal structure, the electromagnetic field theory model of n-layered conductive structure inspected by pulsed eddy current technique was built. The reflection coefficient of the conductive structure to probe is derived by using magnetic vector potential A. It is generalized as the product of n matrix. Furthermore, the frequency-domain response of two coaxial coils probe is derived and expressed in integral expression. According to the diffusion characteristic of low-frequency electromagnetic field and partial difference equation theory, double generalized integral is expanded to series summation. Probe transient response to multi-layered conductive structure is calculated by fast Fourier transform （FFT）. Compared with the results from finite element time-stepping method, it is shown that the theoretic derivation is correct and the calculation method using series expansion and FFT is more effective.

关 键 词：脉冲涡流检测 层叠导体结构 瞬态响应 反射系数 级数展开 傅里叶变换 时步法 

分 类 号：TH878[机械工程—仪器科学与技术]