Abstract To detect and evaluate weld defects, the skin depth and detection ability of magneto-optical imaging (MOI) for weld defects in alternating magnetic field were studied, and the application scope of MOI in alternating magnetic field was determined. A model of magnetic flux leakage testing (MFL) for weld defects is established by finite element method, and the reliability of the model is determined by law analysis and MOI experimental verification. Comparing MFL and eddy current detection with simulation method, the skin effect mechanism and rules of MOI for weld defects in alternating magnetic field are analyzed and obtained. Considering the effect of skin effect, different MFL detection models are established, and the detection ability of MOI for weld defects with different frequencies under corresponding models is studied and obtained. Finally, the MOI experiment is used to verify the results, which are consistent with the simulations. The skin effect rule and detection ability of MOI for weld defects obtained by simulation method can be used as the theoretical basis for practical experiments.

中文翻译：

---

交变磁场下焊缝缺陷磁光成像的趋肤深度及检测能力

摘要 为检测和评价焊缝缺陷，研究了磁光成像（MOI）对交变磁场焊缝缺陷的趋肤深度和检测能力，确定了磁光成像在交变磁场中的应用范围。采用有限元方法建立焊缝缺陷漏磁检测(MFL)模型，通过规律分析和MOI实验验证确定模型的可靠性。将MFL和涡流检测与仿真方法进行比较，分析得到交变磁场下焊缝缺陷MOI的趋肤效应机理和规律。考虑趋肤效应的影响，建立了不同的MFL检测模型，研究并得到了相应模型下MOI对不同频率焊缝缺陷的检测能力。最后，通过MOI实验验证结果，与模拟结果一致。模拟方法得到的焊缝缺陷的趋肤效应规律和MOI检测能力可作为实际实验的理论依据。