用于裂纹检测和表征的脉冲磁通泄漏技术中英文翻译、外文文献翻译

1、外文出处： SensorsandActuatorsA125(2006)1861911外文资料翻译译文（约3000汉字）：用于裂纹检测和表征的脉冲磁通泄漏技术阿里索菲安*，桂云田，Sofiane扎伊哈德斯大学计算和工程学院，Queensgate，Hudders实验室HD1 3DH，英国2004年12月21日收到; 2005年6月16日修订; 于2005年7月15日接受2005年8月29日在线摘要：磁通泄漏（MFL）技术已经广泛用于通过施加磁化的非侵入性检查钢装置。在缺陷可能发生在被检查的结构的近表面和远表面的情况下，当前的MFL技术不能确定它们的大致尺寸。因此，可能必须包括额外的换能器以提供所需

2、的额外信息。本文提出了一种称为脉冲磁通泄漏（PMFL）的新方法，用于裂纹检测和表征。介绍了探头设计和方法。通过理论模拟和实验研究了时频域中的信号特征。结果表明，该技术可以潜在地提供关于缺陷的附加信息。最后，建议潜在的应用程序。2005 Elsevier B.V.保留所有权利。关键词：脉冲磁场; NDTE;缺陷检测和表征1.介绍 磁漏技术广泛应用于管道和油箱地板检查1-7。这种技术需要被测试样品的磁化。磁化产生在一定方向上在试样中流动的磁通量，其理想地垂直于待检测的裂纹的轴。任何缺陷的存在将实现为试样中的通量的磁导率的突然变化。有缺陷的部件的磁导率通常低于无瑕疵的部件，提供高的通量阻力，并迫使它

3、采取不同的路线。在其他路径磁饱和的情况下，一些通量离开样品到周围空间，暂时导致通量“泄漏”。这种泄漏可以通过位于试样表面附近的磁传感器容易地检测到。影响漏磁通分布的缺陷参数是缺陷深度与管壁厚度，长度，宽度，边缘处的锐度和最大深度处的锐度的比率2。在实践中， 磁化装置通常是永磁体或电磁体8,9。对于直流检测，霍尔器件，磁阻和SQUID 10可用于测量漏磁场。对于交流测量，拾波线圈是另一种选择。 MFL技术的优点是其简单性和低成本。与涡流技术相比，该技术对磁性材料的磁性能的变化更加鲁棒，涡流技术也属于电磁NDT技术。像许多电磁技术一样，MFL也是非接触的，这是在线动态检查的非常有用的特征。然而，与

4、涡流不同，MFL仅适用于磁性材料。 在许多应用中期望改进NDT技术的精度，例如管道检查，其中缺陷检测和表征的良好精度可以帮助减少不必要的昂贵的管道替换。为了满足这一要求，本文提出了脉冲MFL技术。与其他MFL技术相比，该技术可能提供关于结构缺陷的更丰富的信息。我们对这个提出的技术的研究提出在本文。在下面的章节中，报告了PMFL的模拟和实验，然后得出结论和进一步的工作。2.脉冲MFL 直流MFL技术提供关于在位置和尺寸方面检测到的缺陷的有限信息。通常，必须确保仅存在一种类型的缺陷，并且这些缺陷只能发生在被检查结构的一侧，以允许精确推断缺陷尺寸，因为该技术仅依赖于一个测量特征，即磁场泄漏强度。在一

5、些实施方式中，它们与其他模态的传感器互补，以允许区分近表面和远表面缺陷。对于交流MFL，检查通常仅对样品的一侧敏感，取决于所选择的激发频率。使用脉冲MFL，探头以方波驱动，丰富的频率组件可以提供来自不同深度的信息，由于皮肤效应。预期我们可以检查较厚的样品的远侧缺陷，同时对近表面缺陷具有良好的灵敏度。此外，我们还应该有额外的信息，如缺陷的位置和大小。脉冲MFL系统的发展是我们对脉冲涡流NDT系统工作的延伸11,12。为了探索该技术的潜力，使用U形铁氧体磁轭设计和构建探针。图。如图1所示：图。 （a）探针和测试充注的示意图和（b）脉冲MFL探针布局和尺寸。 探头的尺寸（mm）。来自霍尼韦尔的SS4

6、90系列13的霍尔器件传感器已经被选择，并被定位在轭的极之间的中间，以测量垂直于样品表面的磁场密度。霍尔传感器的灵敏度为3.125 mV / G。线圈的线圈缠绕在磁轭的顶部水平部分周围，并以矩形波形驱动以激励。在操作期间，控制激励电流以避免铁氧体磁轭磁饱和。使用100kHz采样率的14位数字化进行数据采集。3.模拟有限元模型（FEM）已广泛用于电磁无损检测技术的研究，包括MFL 4。在这项工作中，一个称为FEMLAB的FEM包用于研究表面和子表面裂纹对磁场的影响，并预测系统输出。该包使用有限差分法执行我们所需的瞬态分析。图。图2示出了在模拟中使用的网格模型。围绕插槽创建更精细的网格，以提供更准

7、确的结果。在模拟中使用的所有槽的宽度为1mm。在本文中，表面槽的深度是指从槽的表面到底部末端的槽的长度，并且在模并且在模拟中，其从1mm变化到3mm。子表面槽的深度是样品的顶表面与槽的顶部之间的距离，其在样品的底表面上总是具有开口。子表面槽位于模拟中表面下0.5和1 mm处。图。图3示出了在每个时隙的右手侧边缘上方计算的正常磁场密度。图。图3a和b分别显示了表面和子表面槽的结果。在图中，时间= 0是激励脉冲开始上升时。它由信号的形状表示图。 3.有限元模拟结果：（a）表面槽和（b）表面下裂纹（符号用于识别，而不是实际数据点）。图。 4.不同兴奋的比较 技术可以潜在地通过使用信号的时间信息来区分

8、所检测的时隙的深度以及缺陷的位置。图。 图4示出了计算的法向磁场相对于具有不同激励波形的表面槽的到中心长轴的距离x的曲线图。 表面槽的深度为3 mm。 曲线显示，瞬态的性能略好于10 kHz频率激励，显着优于直流和低频激励。4.实验结果 实验设计给我们一些初步结果，说明该技术的能力。样品具有深度从1至9mm变化的表面槽和具有位置深度范围的子表面槽1.5至7mm。槽的宽度约为1mm。线圈由脉冲宽度为40ms的方波驱动。本节中所示的信号曲线是：初始实验结果表明，最大信号峰值幅度是根据槽的中心长轴的不同正常距离获得的，这取决于槽是在顶表面上还是在底表面上样品。当槽位于表面下方时，由于场扩散，测量场更

9、加扩展。因此，正峰到负峰距离大于槽宽度。这通过图1中绘制的实验结果来说明。槽的宽度约为3mm。表面槽的深度为3mm，埋入槽位于表面下1mm。样品的厚度为10mm。通过在狭缝上以1mm步长手动扫描探针获得结果，并且x = 0是狭缝的中心主轴。每次进行测量时，探针都不移动。对于曲线获取信号幅度。已知使用MFL技术，磁场的极性图。 5.子表面和表面槽的扫描结果图。 6.表面槽深为1，2和3毫米的结果; 激励脉冲的上升沿在时间= 1ms开始（符号用于识别，而不是实际数据点）。如果传感器在裂纹上扫描则更改。曲线显示，使用1mm扫描步长，对于表面和子表面槽，正峰和负峰之间的距离分别为4和8mm。从图中可以

10、看出。如图5所示，信号的幅度随着探头相对于槽轴的相对位置而变化。从现在开始，当探头定位成测量最高信号幅度时，获得所使用的输出信号。正峰值是假设由于对称性，负峰值具有相同的绝对振幅。图。图6显示了来自具有不同深度的表面槽的结果信号。其示出了该技术能够通过使用信号的幅度来区分所检查的时隙的不同深度，只要时隙的位置是已知的。应当注意，实验信号输出相对于时间的所有曲线都被布置成使得激励脉冲的上升沿与时间= 1ms一致。图。图7示出了对于表面和子表面槽获得的信号的比较。它清楚地示出了子表面的信号具有不同的特性，其中它最初缓慢增加并且在某个时间点之后以更快的速率增加。换句话说，子表面槽信号的拐点发生在表面

11、槽信号的拐点之后。通过获取信号的一阶导数可以更清楚地看到这些。实验上发现，探针不能检测到表面下1mm的子表面槽。为了证明区分表面和子表面的能力以及能够区分子表面不连续性的位置深度，使用具有水平长度为93mm的较大轭的另一探针。结果示于图1。如图8所示，这表明次表面缝隙信号的拐点再次出现在表面缝隙信号之后。表面信号的拐点出现在.图。 7.表面和子表面槽信号; 激励脉冲的上升沿在时间= 1ms开始（符号用于识别，而不是实际数据点）。大致相同的时间，而较深位置的子表面槽的拐点发生在稍后的时间，比在更靠近表面的子表面槽的情况下。 所有这些结果表明，拐点可以用于区分检测到的时隙的深度位置。图。 图9示出

12、了信号的频率分析。 曲线支持我们的陈述，即在频率分析中表示为相位的时间信息对于表征缺陷是有用的。 低于50Hz的低频分量似乎不仅区分表面和子表面之间，而且区分表面下面的子表面槽的距离。 位置鉴别似乎也可以使用200 Hz左右的频率实现。 因此，很清楚，槽的距离表面的距离的确定. 面对槽位于，可以方便地使用脉冲MFL技术实现。图。 8.使用较大轭的探头的表面和子表面槽信号; 激励脉冲的上升沿在时间= 1ms开始（符号用于识别，而不是实际数据点）。图。 9.表面和子表面信号的频率分析：（a）幅度，（b）相位（符号用于识别，而不是实际数据点）。5。结论 已经提出和研究了脉冲MFL技术的变体。数值分析

13、和实验研究表明，通过使用时频域中的特征，包括拐点的到达时间，信号幅度和频率分量的相位变化，PMFL显然具有缺陷位置和尺寸的优点。已经表明，该技术除了给出裂纹的相对深度之外，还能够辨别裂纹的位置。探头设计应根据手头的应用进行调整，因为磁轭的尺寸决定了穿透深度，通常较大的磁轭提供更深的穿透。扫描结果还显示出在轭极之间利用磁传感器的线性阵列的潜力，以更好地理解样品条件。模拟结果表明，瞬态或脉冲MFL执行表面和子表面裂纹检查的最佳总体。 PMFL的优点使其可以潜在地适用于铁磁材料的许多应用，包括检测铁磁金属带中的裂纹，其中缺陷可以存在于两侧，而存取限于带的一侧。对于未来的工作，将研究PMFL用于使用特

14、征融合技术的腐蚀检测/表征的能力14,15。该模拟技术也将被改进以进一步探索该技术的潜力。确认作者感谢EPSRC部分资助该项目。参考文献1 B.P.C. Rao, T. Jayakumar, Discontinuity characterisation using elec- tromagnetic methods, J. Non-Destruct. Test. Eval. 2 (2) (2002)2329.2 S. Mukhopadhyay, G.P. Srivastava, Characterisation of metal loss defects from magnetic flux

15、leakage signals with discrete wavelet transform, NDT&E Int. 33 (1) (2000) 5765.3 W. Mao, L. Clapham, D.L. Atherton, Effects of alignment of nearby corrosion pits on MFL, NDT&E Int. 36 (2) (2003) 111116.4 M. Katoh, N. Masumoto, K. Nishio, T. Yamaguchi, Modeling of the yoke-magnetization in MFL-testin

16、g by finite elements, NDT&E Int. 36 (7) (2003) 479486.5 J.C. Drury, A. Marino, A comparison of the magnetic flux leakage and ultrasonic methods in the detection and measurement of corro- sion pitting in ferrous plate and pipe, in: Proceedings of the 15th World Conference on Non-destructive Testing,

17、Roma, 2000.6 C.R. Coughlin, L. Clapham, D.L. Atherton, Effects of stress on MFL responses from elongated corrosion pits in pipeline steel* 1, NDT&E Int. 33 (3) (2000) 181188.7 M. Afzal, S. Udpa, Advanced signal processing of magnetic flux leakage data obtained from seamless gas pipeline, NDT&E Int.

18、35 (7) (2002) 449457.8 K. Mandal, T. Cramer, D.L. Atherton, The study of a racetrack- shaped defect in ferromagnetic steel by magnetic Barkhausen noise and flux leakage measurements, J. Magnet. Magnet. Mater. 212 (12) (2000) 231239.9 M. Goktepe, Non-destructive crack detection by capturing local flu

19、x leakage field, Sens. Actuators A: Phys. 91 (12) (2001) 7072.10 H.-J. Krause, M.v. Kreutzbruck, Recent developments in SQUID NDE, Physica C: Supercond. 368 (14) (2002) 7079.11 A. Sophian, G.Y. Tian, D. Taylor, J. Rudlin, Design of a pulsed eddy current sensor for detection of defects in aircraft la

20、p-joints, Sens. Actuators A: Phys. 101 (12) (2002) 9298.12 A. Sophian, G.Y. Tian, D. Taylor, J. Rudlin, A feature extraction technique based on principal component analysis for pulsed eddy current NDT, NDT&E Int. 36 (1) (2003) 3741.13 Honeywell, SS490 Series Miniature Ratiometric Linear Solid State

21、Sensors, 2000.14 G.Y. Tian, A. Sophian, Reduction of lift-off effects for pulsed eddy current NDT, NDT&E Int. 38 (4) (2005) 319324.15 G.Y. Tian, A. Sophian, Defect classification using a new feature for pulsed eddy current sensors, NDT&E Int. 38 (1) (2005) 7782.传记Ali Sophian博士于1998年获得BE（荣誉）学士学位，2004

22、年获得英国哈德斯菲尔德大学的电子工程学博士学位。他目前是哈德斯菲尔德大学计算与工程学院的研究员。他的研究兴趣包括涡流NDT系统设计，信号处理和嵌入系统。自从他开始了由TWI有限公司共同发起的博士项目以来，他一直致力于电磁无损检测系统。桂云田博士于1985年和1988年分别在四川大学（中国成都）获得计量学与仪器学士学位和精密工程硕士学位。在四川大学担任副教授3年后，他于1995年在英国攻读博士学位，并于1998年在德比大学获得学位。他目前是计算机学院的读者，工程，英国哈德斯菲尔德大学和四川大学客座教授。他在传感器，智能仪表，非破坏性测试，数字信号处理，计算机视觉和微机电领域拥有多元化和积极的研究

23、系统（MEMS），由EPSRC，皇家学会，皇家工程学院和世界级工业资助。他在上述领域出版了100多本英文或中文的书籍和论文，并成功地监督了几位研究员，如博士，博士和硕士研究生。他是IEEE的高级成员，也是国际期刊和会议的定期审阅者。So fi ane Zairi博士于1996年获得了Monastir大学应用物理学和半导体理学学士学位（荣誉）。他于1997年在法国获得利昂里昂INSA的微电子学硕士学位。然后，他在2001年在法国里昂的中央法学院获得了集成传感器的博士学位。后来，他加入了在英国格拉斯哥的斯特拉斯克莱德大学的一个文后的项目。这个由SHEFC理事会资助的项目，其中制造了涉及MOEMS和

24、RF MEMS领域的微系统的多功能单元库。 Zairi博士对嵌入式微系统领域和使用HDL和基于FEM的分析方法的软件建模表现出极大的兴趣。他目前是哈德斯菲尔德大学计算与工程学院的研究助理。2外文资料原文（与课题相关，至少1万印刷符号以上）：Pulsed magnetic flux leakage techniques for crack detection and characterisationAli Sophian , Gui Yun Tian, Sofiane ZairiSchool of Computing and Engineering, University of Hudderse

25、ld, Queensgate, Hudderseld HD1 3DH, UKReceived 21 December 2004; received in revised form 16 June 2005; accepted 15 July 2005Available online 29 August 2005AbstractMagnetic flux leakage (MFL) techniques have been widely used for non-intrusively inspecting steel installations by applying magnetizatio

26、n. In the situations where defects may take place on the near and far surfaces of the structure under inspection, current MFL techniques are unable to determine their approximate size. Consequently, an extra transducer may have to be included to provide the extra information required. This paper pre

27、sents a new approach termed as pulsed magnetic flux leakage (PMFL) for crack detection and characterisation. The probe design and method are introduced. The signal features in timefrequency domains are investigated through theoretical simulations and experiments. The results show that the technique

28、can potentially provide additional information about the defects. Lastly, potential applications are suggested. 2005 Elsevier B.V. All rights reserved.Keywords: Magnetic flux leakage; Pulsed magnetic field; NDT&E; Defect detection and characterisation1. IntroductionMagnetic flux leakage techniques a

29、re widely used for pipe and tank floor inspection 17. This technique requires magnetisation of the specimen under test. The magnetisation generates magnetic flux flowing in the specimen in a certain direction, which is ideally perpendicular to the axis of the crack to be detected. The presence of an

30、y flaws will imple- ment as an abrupt change of magnetic permeability to the flux in the specimen. The permeability of the flawed part is gen- erally lower than flawless parts, providing high resistance to the flux and forcing it to take a different route. In cases where the other routes are magneti

31、cally saturated, some flux leaves the specimen to the surrounding space temporarily causing flux leakage. This leakage is readily detectable by a magnetic sensor located in the proximity of the specimen surface. The defect parameters that affect the distribution of the leakage flux are the ratio of

32、depth of the defect to the thickness of the pipe wall, length, width, sharpness at the edges and sharpness at the maximum depth 2. In practice,the magnetisation device is usually a permanent magnet or an electromagnet 8,9. For dc inspection, Hall devices, mag- netoresistives and SQUIDs 10 can be use

33、d to measure the leakage field. For ac measurements, pick-up coils are another alternative. The advantage of MFL techniques is its simplicity and low cost. The technique is more robust to the variation of magnetic properties in magnetic materials compared to eddy current techniques, which belong to

34、electromagnetic NDT techniques as well. Like many electromagnetic techniques, MFL is also non-contact, which is a very useful feature for on-line dynamic inspection. Unlike eddy currents, however, MFL only works with magnetic materials.Improvement in accuracy in NDT techniques is desired in many app

35、lications, such as pipe inspection where good accuracy in defect detection and characterisation can help reduce unnecessary costly pipe replacements. To meet this requirement, pulsed MFL technique is proposed in this paper. The technique potentially offers richer information about structural defects

36、 compared to the other MFL techniques. Our study on this proposed technique is presented in this paper. In the following sections, simulation and experiments on PMFL are reported, followed by conclusions and further work.2. Pulsed MFLThe dc MFL technique provides limited information on the defects d

37、etected in terms of location and sizing. Gen- erally, it has to be ensured that only one type of defect is present and these defects can only happen on one side of the inspected structure to allow accurate inference of the defect size, because the technique only relies on one mea- surement feature,

38、i.e. the magnetic field leakage intensity. In some implementations they are complemented with sen- sors of other modality to allow discrimination of near and far surface defects. With ac MFL, the inspection is generally sensitive to only one side of the sample depending on the excitation frequency c

39、hosen. With pulsed MFL, the probe is driven with a square waveform and the rich frequency com- ponents can provide information from different depths due to the skin effects. It is expected that we could inspect thicker samples for far side defects and at the same time has good sen- sitivity for near

40、 surface defects. In addition, we should also have additional information such as the location and size of defects. The development of the pulsed MFL system is an extension of our work on pulsed eddy current NDT systems 11,12.To explore the potential of the technique, a probe was designed and built

41、using a U-shaped ferrite yoke. Fig. 1 shows the dimensions of the probe in mm. A Hall device sensor from Honeywells SS490 family 13 has been chosen and is positioned halfway between the yokes poles to measure the magnetic field density normal to the sample surface. The Hall sensor has a sensitivity

42、of 3.125 mV/G. A coil of wire is wound around the top horizontal part of the yoke and driven with a rectangular waveform for excitation. During operation, the excitation current is controlled to avoid the ferrite yoke getting magnetically saturated. Data acquisition is performed using a 14-bit digit

43、isation at 100 kHz sampling rate.Fig. 1. (a) Illustration of the probe and a test ample and (b) pulsed MFL probe layout and dimensions.3. SimulationFinite element modelling (FEM) has been widely used for the study of electromagnetic NDT techniques, including MFL 4. In this work, a FEM package called

44、 FEMLAB is used to study the effects of surface and sub-surface cracks on the magnetic field and to predict the system outputs. The package uses the finite difference method to perform tran- sient analysis that is required for our purpose. Fig. 2 shows the meshed model used in the simulation. Finer

45、meshes are created surrounding the slot to give more accurate results. The width of all the slots used in the simulation is 1 mm. In this article, the depth of the surface slots refers to the length of the slot from the surface to the bottom tip of the slot and in the simulation it is varied from 1

46、to 3 mm. The depth of sub-surface slots is the distance between the top surface of the sample to the top of the slots that always have an opening on the bottom surface of the sample. The sub-surface slots are located 0.5 and 1 mm below the surface in the simulation.Fig. 3 shows the calculated normal

47、 magnetic field density above the right hand side edge of the each slot. Fig. 3a and b show the results from surface and sub-surface slots respec- tively. In the figures, time = 0 is when the excitation pulse starts rising. It is shown by the shapes of the signals that the technique can potentially

48、discriminate the depths of the slots detected and also the position of the defect by using temporal information of the signals.Fig. 4 shows the plots of the calculated normal magnetic field against the distance x to the central major axis of a sur- face slot with different excitation waveforms. The

49、surface slots depth is 3 mm. The plots show that the transient per- forms slightly better than the 10 kHz frequency excitation and significantly better than both the dc and the low frequency excitations.Fig. 3. FEM simulation results: (a) surface slots and (b) sub-surface cracks (symbols are for ide

50、ntification, not actual data points).Fig. 4. Comparison of different excitations.4. Experimental resultsThe experiments are designed to give us some initial results that illustrate the capabilities of the technique. The samples have surface slots with depths varying from 1 to 9 mm and sub-surface sl

51、ots with location depths ranging from0.5 to 7 mm. The width of the slots is approximately 1 mm.The coil is driven with a square waveform with a pulse width of 40 ms. The plots of signals shown in this section are: initial experiment results show that the highest signal peak ampli- tudes are obtained

52、 at different normal distances from the slots central major axis depending whether the slot is on the top surface or on the bottom surface of the sample. When the slot is located below the surface, the measured field is more spread out due to field dispersion. Therefore, the positive peak to negativ

53、e peak distance is larger than the slot width. This is illustrated by experimental results plotted in Fig. 5. The slots width is approximately 3 mm. The depth of the surface slot is 3 mm and the buried slot is located 1 mm below the surface. The thickness of the sample is 10 mm. The results were obt

54、ained by manually scanning the probe over the slots with a 1 mm step and x = 0 being the central major axis of the slots. The probe is unmoved every time a measurement is taken. The signal amplitudes are taken for the plot. It is known that with MFL techniques, the polarity of the magnetic fieldFig.

55、 5. Scanning results of sub-surface and surface slots.Fig. 6. Results with surface slots with depths of 1, 2 and 3 mm; the rising edge of the excitation pulse initiates at time=1 ms (symbols are for identification, not actual data points).changes if the sensor is scanned over a crack. The plots show

56、 that with the 1 mm scanning step used, the distances between the positive and negative peaks are 4 and 8 mm for the surface and sub-surface slots, respectively.As can be seen in Fig. 5, the amplitude of the signal varies with the relative position of the probe to the slot axis. From now on, the out

57、put signals used are obtained when the probe is such positioned that the highest signal amplitude is mea- sured. The positive peaks are taken with the assumption that the negative peaks have the same absolute amplitudes due to symmetry. Fig. 6 shows the resulting signals from sur- face slots with di

58、fferent depths. It shows that the technique is able to differentiate different depths of the inspected slots by using the amplitudes of the signals, provided that the location of the slot is known. It should be noted that all plots of the experimental signal output against time have been arranged so that the rising edge of the excitation pulse coincides with time = 1 ms.Fig. 7 shows the comparison of the signals obtained for bo