Mechanism analysis of influence of surface-breaking orientation on magnetic leakage field distribution
Mechanism analysis of influence of surface-breaking orientation on magnetic leakage field distribution
复制标题
表面断裂方向对漏磁场分布影响的机理分析
DOI：
10.7498/aps.66.048102
复制
发表时间：
2017-02-20
影响因子：
1
通讯作者：
Su Ling-Xin
中科院分区：
文献类型：
--
作者：
Wu De-Hui;Liu Zhi-Tian;Su Ling-Xin
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.根据漏磁信号与缺陷几何特征的关系，对缺陷进行了评价。本文建立了铁磁材料中任意取向表面破裂缺陷漏磁场的三维数学模型。首先，采用有限长矩形槽作为表面断裂缺陷的简化表示。在此基础上，对不同表面破断方向的槽壁磁荷密度进行了理论分析。漏磁场的分布最终可以通过矢量合成得到。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.结果表明，随着缺陷取向与磁场夹角的增大，漏磁场的水平分量增大，其单峰的突出程度增大。但与此同时，垂直分量呈现双峰分布。该模型能有效描述缺陷取向对漏磁信号的影响，为优化漏磁检测器和提高缺陷检测质量提供了依据。
Magnetic flux leakage (MFL) has been widely applied to the nondestructive testing (NDT) of ferromagnetic materials due to its simple operation, low cost, and steady signal. Its defects are evaluated based on the relationship between MFL signal and the geometrical characteristic of defect. In this paper, a three-dimensional (3D) mathematical model is developed for the magnetic leakage field of surface- breaking defects that are arbitrarily oriented inside ferromagnetic material. Firstly, a finite-length rectangular slot is used as a simplified and convenient representation of a surface-breaking defect. Then, the magnetic charge densities of slot walls in different surface-breaking orientations are analyzed theoretically. The distribution of the magnetic leakage field can ultimately be derived by vector synthesis. Both simulations and experiments are conducted to analyze the magnetic leakage field distributions in different magnetization orientations. The results show that with increasing the angle between the defect orientation and the magnetic field, the horizontal component of the leakage magnetic field increases as demonstrated by increasing the prominence of its single peak. At the same time, however, the vertical component shows a bimodal distribution. The proposed model can effectively describe the influence of defect orientation on MFL signals, which can offer practical guidelines for optimizing MFL detectors and improving defect assessment.