管道环焊缝缺陷漏磁检测信号仿真分析

Numerical simulation on magnetic flux leakage detection signal for pipeline girth weld defects

文中基于漏磁检测技术基本原理,对油气管道环焊缝常见的缺陷类型,采用有限元数值模拟仿真的方法进行分析。选取管壁厚为9 mm、直径为529 mm的L415管线钢,应用ANSYS有限元软件对错边、咬边和凹坑等管道环焊缝缺陷磁化后产生的漏磁场特征信号进行模拟仿真,得到了描述漏磁场特征的磁通密度分布曲线,与试验测试的漏磁信号特征是一致的。通过改变不同缺陷的大小,经过对比分析,得出管道不同缺陷形式和尺寸下的漏磁场分布规律,为管道缺陷漏磁信号特征识别提供理论基础和实践依据。

The characteristics of magnetic field generated after the magnetization of pipeline were numerically simulated with finite element method based on magnetic flux leakage(MFL)principle.The ANSYS finite element software was used to perform the simulation for misalignment,undercut and pit defects in pipeline girth weld for L415 pipeline steel with wall thickness of 9 mm and diameter of 529 mm.The magnetic flux density distribution curves describing the features of magnetic leakage field were obtained,which was consistent with experiments.By changing the size of defects,the distribution rule of leakage magnetic field for different defect forms and sizes could be observed after comparative analysis.It provided theoretical basis and practical reference for characteristics identification of pipeline defects magnetic flux leakage signal.