表面缺陷的方向性对漏磁场分布的影响

发布时间：2018-03-07 23:22

本文选题：漏磁检测　切入点：磁偶极子　出处：《物理学报》2017年04期 　论文类型：期刊论文

【摘要】：由于漏磁检测(MFL)具有操作简单、成本低廉、信号稳定等特点,已被广泛应用于铁磁材料的无损检测.在MFL领域,实现缺陷评估的关键是对漏磁信号与缺陷几何特征之间的关系进行准确描述.本文建立了一个任意方向的表面缺陷漏磁场分布的三维数学模型.首先,将表面缺陷近似为一个有限长的矩形槽来进行描述;然后,从理论上分析了不同缺陷方向下槽壁磁荷密度的变化规律;最后,通过矢量合成得到了有向缺陷的漏磁场分布.开展了仿真和实验,对缺陷在不同磁化方向下的漏磁场分布进行了分析.实验结果表明,缺陷的MFL分布与方向性密切相关.随着与磁化方向夹角增大,缺陷漏磁场水平分量亦增加,单峰性也越突出;但垂直分量却随夹角的增大而呈现双峰分布.所建模型能有效地描述缺陷的方向性对漏磁场分布影响,对优化MFL检测器设计和提高缺陷评估质量有实际指导意义.
[Abstract]:Due to its simple operation, low cost and stable signal, MFL has been widely used in nondestructive testing of ferromagnetic materials. The key to implement defect evaluation is to accurately describe the relationship between magnetic flux leakage signal and geometric characteristics of defects. In this paper, a three-dimensional mathematical model of magnetic flux leakage distribution of surface defects in any direction is established. The surface defect is described as a rectangular slot of finite length. Then, the variation of magnetic charge density of the slot wall in different defect directions is analyzed theoretically. The leakage magnetic field distribution of directed defects is obtained by vector synthesis. Simulation and experiments are carried out to analyze the magnetic leakage field distribution of defects in different magnetization directions. The experimental results show that, The MFL distribution of defects is closely related to directionality. With the increase of the angle with the magnetization direction, the horizontal component of the leakage magnetic field of the defect also increases, and the singularity becomes more prominent. However, the vertical component presents a bimodal distribution with the increase of the angle, and the model can effectively describe the effect of defect directivity on the leakage magnetic field distribution, and has practical significance for optimizing the design of MFL detector and improving the quality of defect evaluation.
【作者单位】：厦门大学航空航天学院;
【基金】：国家自然科学基金(批准号:51177141,51677158)资助的课题~~
【分类号】：O441.2

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