电磁超声无损检测由于具有无需耦合剂、检测速度快、效率高等优点而被应用于众多工程领域。文章研究了碳素钢电磁超声无损检测数值模拟中的重点问题——磁性材料内部磁场分布的数值模拟方法。以麦克斯韦方程组为理论基础，基于等效磁极化法开发了铁磁材料内部的磁化强度计算方法和程序。数值模拟中采用有限元-边界元混合方法，并采用等效电流模型计算永磁体磁场分布，以实现铁磁性材料内部三维静态磁场数值模拟。通过对数值模拟结果的分析及与ANSYS计算结果进行比对，验证了方法的有效性。

Electromagnetic Acoustic Technique(EMAT) has been widely used in many engineering applications due to its advantages over other conventional Ultrasonic Testing(UT) techniques in terms of non-contact inspection, rapid scanning and high evaluation efficiency. In this paper, an algorithm and the corresponding numerical code have been developed for simulation of the magnetization in the ferromagnetic material based on the Maxwell-equations and the equivalent polarization method. The numerical simulation code has been developed on the basis of the FEM-BEM hybrid method, and the magnetic current model is adopted to calculate the magnetic field due to the permanent magnet. The validities of the proposed algorithm and the developed numerical code are demonstrated via comparison between the numerical results of ANSYS and the present method.