通过磁折射理论及相应的有限元模型分析了加厚过渡区的磁场分布特性,主要包括由于内外径变化产生的空间磁场和由于壁厚变化产生的磁感应强度的非均匀性;找到并确认了变径产生的空间磁场是造成漏磁检测信号基线漂移的主要原因,并通过差分法进行了消除;同时,也发现了变壁厚区磁化的非均匀性会导致同当量缺陷的漏磁场信号不一致,通过分析壁厚及磁化强度对漏磁场的影响,提出深度饱和磁化方法.结果表明:该方法能有效消除钻杆过渡带区域的背景磁场干扰并保证信号一致性,使漏磁法能适用于钻杆加厚过渡带的检测.

The magnetic field refraction theory and the corresponding finite element model was carried out to analyze the magnetic field distribution of the upset transition zone .The background magnetic field caused by radius changing and the non-uniformity of magnetization caused by wall thickness changing are the main features of the upset transition zone .Then ,the background field caused by ra-dius changing was confirmed to be the reason for baseline shifting ,and this effect was eliminated by the differentiation method .At the same time ,the non-uniformity of magnetization caused by wall thickness changing was found to be the reason which makes the magnitudes of leakage field different for the defects with same dimension .After analyzing the influence of wall thickness and magnetization on magnetic leakage field ,a deep magnetic saturation method was proposed .The results show that this method can effectively eliminate the background field in the upset transition zone and guarantee the cons

利用ANSYS有限元软件进行仿真模拟,对超磁致伸缩执行器（GMA,Giant Magnetostrictive Actuator）的磁路结构进行了分析和优化.根据磁致伸缩棒内磁场均匀性好,场外漏磁小的设计目标,利用极性相反的双永磁补偿原理,提出了一种新型的内置式永磁组合偏置结构,使得沿磁致伸缩棒长方向磁场分布均匀的同时,偏置磁场和激励磁场都形成良好的闭合磁路.ANSYS分析结果表明,棒中偏置磁场不均匀度为3.51%,激励磁场不均匀度为8.73%,均满足不均匀度小于10%的设计目标;在执行器指定位置（距离GMA 7cm）的总漏磁场强度为30.4 A/m,符合实际应用的标准要求（〈80 A/m）.

The magnetic circuit of giant magnetostrictive actuator(GMA) was analysed and optimized with finite element software ANSYS.According to the design goals of high homogeneity of magnetic field and low magnetic flux leakage,a novel magnetic circuit biased by the combination of built-in permanent magnets was proposed in the base of compensation principle of dual-permanent magnets with contrary polarity.Magnetic field along the direction of the length of giant magnetostrictive rod was homogeneous,while well-closed magnetic circuits were informed in both biased magnetic field and driving magnetic field.According to the results from ANSYS analysis,the unevenness of the bias magnetic field and driving magnetic field is 3.51% and 8.73% respectively,which are less than 10%.The total magnetic leakage in the specified location(7 cm from the GMA) is 30.4A/m,meeting the standard of practical application(80A/m).

从漏磁的原理出发,通过对缺陷漏磁场进行分析,确立漏磁场与裂纹深度、宽度以及提离值的关系。在此基础上设计一个以工业控制计算机为上位机、以单片机为下位机构成的漏磁检测系统,介绍系统的操作流程。该检测系统对钢铁材料外表面缺陷和内部缺陷都具有较高的检出能力。

This paper starts from the theory of magnetic flux leakage and analysis of defect on magnetic flux leakage and establishes re- lationship of the leakage magnetic field and the crack depth, width and lift-off value. Magnetic flux leakage testing system is designed with industrial control computer as upper machine, single chip as the hypogyny. The operation process of the system is introduced. The system shows high detection ability on the iron and steel material surface and internal defects.

采用Visual Basic语言,编制了有限元分析软件,并对永磁直流电动机进行空载计算,得出了空载状态下的磁场分布图和气隙磁密分布曲线,并提出了减少电动机漏磁的改进方法。

In this paper introduces a way to establish the finite element analysis software based on the Visual Basic language.And then use it to calculate the motor no-load characteristic,get the no-load magnetic field distribution curve of the motor and the flux density distribution curve.And propose a method to reduce the motor magnetic flux leakage.

YIG调谐器件在现代电子对抗系统中应用广泛，但针对YIG调谐器件的漏磁特性缺乏定量分析。通过对YIG调谐器件的漏磁特性建模及仿真，特别是针对测试样品射频连接器区域磁场仿真和漏磁测量，得到其漏磁分布曲线，实现了YIG调谐器件的漏磁定量分析，为YIG调谐器件工程应用中抗漏磁干扰设计提供了依据。此外，该研究对于有效降低YIG调谐器件的漏磁干扰，提高整机系统技术指标和改善工作性能有着一定的指导意义。

YIG-tuned devices is widely used in modern electronic countermeasures system, but their flux leakage characteristic is seldom reported. In this paper,modeling and simulation is given for flux leakage distribution of YIG-tuned device by Maxwell 3D softwere, providing a quantitative analysis of field leakage distribution. The analysis result supplies a design reference for anti-flux-leakage disturbance in engineering applications of YIG-tuned devices. Additionally, this research is of guidance for degrading the flux leakage disturbance of YIG-tuned device, and resultantly improving the performance of overall unit related to the YIG-tuned devices.