基于远场涡流法的管道缺陷识别的有限元仿真研究

摘要

远场涡流(RFEC)法是无损检测的重要方法之一,相对于其他无损检测技术而言更具优势.在基于远场涡流原理的基础上,利用有限元方法对远场涡流现象和二维轴对称缺陷进行了仿真和分析.首先,从麦克斯韦方程出发,对远场涡流进行数学建模,为有限元分析提供理论指导；其次,利用有限元法建立仿真环境,并对远场涡流现象进行二维仿真,借此设计出实验装置并确定了激励参数；最后,对轴向上不同位置、宽度和深度的缺陷进行分类对比仿真,研究了缺陷信号间的相互作用,确定了缺陷量化特征量,优化了缺陷信号.为以后的三维仿真和缺陷位置、尺寸及管道耗损的定量识别提供了理论依据.%Remote field eddy current( RFEC) testing is an important method in nondestructive testing( NDT) and has more advantages than other nondestructive testing methods. On the basis of RFEC theory, RFEC and axis-symmetric defects in two-dimension are simulated and analyzed by using finite element method ( FEM). Firstly, mathematical model of RFEC is built up on the basis of Maxwell equation and provides guidance on the finite element analysis. Secondly, the simulation environment is built up with finite element software, and RFEC is simulated in two-dimension, the results determine the parameters of the excitation source and the testing device. Finally, the simulation is made among multiple axis-symmetric defects in two-dimension, and the results are compared to illustrate interactions among defect signals and find the characteristic quantities to identify the defects. The research provides a valueable reference on the three-dimension simulation, testing device design and defects identification.