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公开(公告)号：US5698977A
公开(公告)日：1997-12-16
申请号：US490441
申请日：1995-06-05
申请人： John W. Simpson , James P. Fulton , Russell A. Wincheski , Ronald G. Todhunter , Min Namkung , Shridhar C. Nath
发明人： John W. Simpson , James P. Fulton , Russell A. Wincheski , Ronald G. Todhunter , Min Namkung , Shridhar C. Nath
CPC分类号： G01N27/9033 , G01N27/902
摘要： Flux-focusing electromagnetic sensor using a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. A ferrous shield isolates a high-turn pick-up coil from an excitation coil. Use of the magnetic shield produces a null voltage output across the receiving coil in presence of an unflawed sample. Redistribution of the current flow in the sample caused by the presence of flaws, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. Maximum sensor output is obtained when positioned symmetrically above the crack. By obtaining position of maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. Accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output resulting in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip enabling the search region to be clearly defined. Under low frequency operation, material thinning due to corrosion causes incomplete shielding of the pick-up coil. Low frequency output voltage of the probe is therefore a direct indicator of thickness of the test sample. Fatigue testing a conductive material is accomplished by applying load to the material, applying current to the sensor, scanning the material with the sensor, monitoring the sensor output signal, adjusting material load based on the sensor output signal of the sensor, and adjusting position of the sensor based on its output signal.
摘要翻译： 使用铁磁通量聚焦透镜的磁通聚焦电磁传感器简化了检查，增加了高导电性材料中疲劳裂纹和材料损失的可检测性。 铁屏蔽将高转弯拾取线圈与励磁线圈隔离。 使用磁屏蔽在存在未裂纹的样品的情况下，在接收线圈上产生零电压输出。 由于存在缺陷导致样品中的电流重新分布，消除了屏蔽状况，产生了大的输出电压，产生了明确的明确的缺陷信号。 当对称地位于裂纹上方时获得最大传感器输出。 通过获得最大传感器输出的位置，可以跟踪故障并定位其尖端周围的区域。 传感器的两个独特功能增强了尖端位置的精度; 探头输出的非常高的信噪比导致故障之间的非常平滑的信号峰值，以及在裂纹尖端周围的小区域外的迅速衰减的传感器输出，使得能够清楚地定义搜索区域。 在低频操作下，由于腐蚀引起的材料变薄会引起拾音线圈的不完全屏蔽。 因此，探头的低频输出电压是测试样品厚度的直接指示。 通过对材料施加负载，向传感器施加电流，用传感器扫描材料，监测传感器输出信号，基于传感器的传感器输出信号调整材料载荷，以及调整位置 该传感器基于其输出信号。
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公开(公告)号：US5648721A
公开(公告)日：1997-07-15
申请号：US343740
申请日：1994-11-22
CPC分类号： G01N27/902 , G01N27/9033
摘要： A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks about circular fasteners and other circular inhomogeneities in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil, The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal.By rotating the probe in a path around a circular fastener such as a rivet while maintaining a constant distance between the probe and the center of a rivet, the signal due to current flow about the rivet can be held constant. Any further changes in the current distribution, such as due to a fatigue crack at the rivet joint, can be detected as an increase in the output voltage above that due to the flow about the rivet head.
摘要翻译： 使用铁磁通量聚焦透镜的助焊剂聚焦电磁传感器简化了检查，增加了高导电性材料中的圆形紧固件和其他圆形不均匀性的疲劳裂纹的可检测性。 该器件的独特特征是将铁氧体屏蔽层与激励线圈隔离开来，使得磁屏蔽体在无裂纹样品存在的情况下在接收线圈上产生零电压输出。 然而，由于存在缺陷导致的样品中的电流的再分布消除了屏蔽状况，产生了大的输出电压，产生了明确的明确的缺陷信号。 通过围绕诸如铆钉的圆形紧固件的路径旋转探头，同时保持探头和铆钉中心之间的恒定距离，由于围绕铆钉的电流流动的信号可以保持恒定。 由于铆钉头周围的流动，输出电压的增加可以被检测到电流分布的任何进一步变化，例如由于铆钉接头处的疲劳裂纹引起的。
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3.发明授权Radially focused eddy current sensor for detection of longitudinal flaws in metallic tubes 失效用于检测金属管纵向缺陷的径向聚焦涡流传感器
公开(公告)号：US5942894A
公开(公告)日：1999-08-24
申请号：US527741
申请日：1995-09-13
申请人： Russell A. Wincheski , John W. Simpson , James P. Fulton , Shridhar C. Nath , Ronald G. Todhunter , Min Namkung
发明人： Russell A. Wincheski , John W. Simpson , James P. Fulton , Shridhar C. Nath , Ronald G. Todhunter , Min Namkung
CPC分类号： G01N27/902
摘要： A radially focused eddy current sensor detects longitudinal flaws in a metal tube. A drive coil induces eddy currents within the wall of the metal tube. A pick-up coil is spaced apart from the drive coil along the length of the metal tube. The pick-up coil is positioned with one end thereof lying adjacent the wall of the metal tube such that the pick-up coil's longitudinal axis is perpendicular to the wall of the metal tube. To isolate the pick-up coil from the magnetic flux of the drive coil and the flux from the induced eddy currents, except the eddy currents diverted by a longitudinal flaw, an electrically conducting material high in magnetic permeability surrounds all of the pick-up coil except its one end that is adjacent the walls of the metal tube. The electrically conducting material can extend into and through the drive coil in a coaxial relationship therewith.
摘要翻译： 径向聚焦的涡流传感器检测金属管中的纵向缺陷。 驱动线圈在金属管的壁内引起涡流。 拾取线圈沿着金属管的长度与驱动线圈间隔开。 拾取线圈的一端位于金属管的壁附近，使得拾取线圈的纵轴垂直于金属管的壁。 为了将拾取线圈与驱动线圈的磁通和来自感应涡流的磁通隔离，除了由纵向缺陷转移的涡流之外，导磁体的磁导率高，围绕着所有的拾取线圈 除了其与金属管的壁相邻的一端。 导电材料可以以与其同轴的关系延伸进入并穿过驱动线圈。
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4.发明授权
公开(公告)号：US5847562A
公开(公告)日：1998-12-08
申请号：US852990
申请日：1997-05-08
CPC分类号： G01B7/105
摘要： A thickness gauging instrument uses a flux focusing eddy current probe and two-point nonlinear calibration algorithm. The instrument is small and portable due to the simple interpretation and operational characteristics of the probe. A nonlinear interpolation scheme incorporated into the instrument enables a user to make highly accurate thickness measurements over a fairly wide calibration range from a single side of nonferromagnetic conductive metals. The instrument is very easy to use and can be calibrated quickly.
摘要翻译： 厚度测量仪使用通量聚焦涡流探头和两点非线性校准算法。 由于探头的简单解释和操作特性，该仪器体积小巧便携。 结合到仪器中的非线性插值方案使用户能够在非铁磁导电金属的单侧在相当宽的校准范围内进行高精度的厚度测量。 该仪器非常易于使用，可以快速校准。
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公开(公告)号：US5617024A
公开(公告)日：1997-04-01
申请号：US649851
申请日：1996-05-08
申请人： John W. Simpson , C. Gerald Clendenin , James P. Fulton , Russell A. Wincheski , Ronald G. Todhunter , Min Namkung , Shridhar C. Nath
发明人： John W. Simpson , C. Gerald Clendenin , James P. Fulton , Russell A. Wincheski , Ronald G. Todhunter , Min Namkung , Shridhar C. Nath
CPC分类号： G01N27/9033 , G01N27/902
摘要： A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil. The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal.The maximum sensor output is obtained when positioned symmetrically above the crack. Hence, by obtaining the position of the maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. The accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output which results in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip which enables the region for searching to be clearly defined. Under low frequency operation, material thinning due to corrosion damage causes an incomplete shielding of the pick-up coil. The low frequency output voltage of the probe is therefore a direct indicator of the thickness of the test sample.
摘要翻译： 使用铁磁通量聚焦透镜的助焊剂聚焦电磁传感器简化了检查并增加了高导电性材料中的疲劳裂纹和材料损失的可检测性。 该器件的独特之处在于，铁芯屏蔽了高频匝线圈与励磁线圈的隔离。 显示了使用磁屏蔽，在存在无裂纹的样品的情况下，在接收线圈上产生零电压输出。 然而，由于存在缺陷导致的样品中的电流的再分布消除了屏蔽状况，产生了大的输出电压，产生了明确的明确的缺陷信号。 当对称地位于裂缝上方时获得最大传感器输出。 因此，通过获得最大传感器输出的位置，可以跟踪故障并定位其尖端周围的区域。 通过传感器的两个独特功能增强了尖端位置的精度; 探头输出的非常高的信噪比导致故障之间的非常平滑的信号峰值，以及在裂纹尖端周围的小区域外的迅速衰减的传感器输出，使得该区域能够被清楚地定义。 在低频操作下，由于腐蚀损坏引起的材料变薄会导致拾取线圈的不完全屏蔽。 因此，探头的低频输出电压是测试样品厚度的直接指示。
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公开(公告)号：US6054210A
公开(公告)日：2000-04-25
申请号：US846505
申请日：1997-04-09
CPC分类号： C08G73/1042 , H01F1/26 , H01F41/0246 , Y10T428/256
摘要： A molded magnetic article and fabrication method are provided. Particles of ferromagnetic material embedded in a polymer binder are molded under heat and pressure into a geometric shape. Each particle is an oblate spheroid having a radius-to-thickness aspect ratio approximately in the range of 15-30. Each oblate spheroid has flattened poles that are substantially in perpendicular alignment to a direction of the molding pressure throughout the geometric shape.
摘要翻译： 提供了一种成型的磁性制品和制造方法。 嵌入聚合物粘合剂中的铁磁材料的颗粒在热和压力下成型为几何形状。 每个颗粒是半径对厚度纵横比大约在15-30的范围内的扁圆球体。 每个扁圆球体具有平整的极，其基本上在整个几何形状中与成型压力的方向垂直对齐。
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公开(公告)号：US06888346B2
公开(公告)日：2005-05-03
申请号：US10021683
申请日：2001-11-28
CPC分类号： G01N27/9033
摘要： A giant magnetoresistive flux focusing eddy current device effectively detects deep flaws in thick multilayer conductive materials. The probe uses an excitation coil to induce eddy currents in conducting material perpendicularly oriented to the coil's longitudinal axis. A giant magnetoresistive (GMR) sensor, surrounded by the excitation coil, is used to detect generated fields. Between the excitation coil and GMR sensor is a highly permeable flux focusing lens which magnetically separates the GMR sensor and excitation coil and produces high flux density at the outer edge of the GMR sensor. The use of feedback inside the flux focusing lens enables complete cancellation of the leakage fields at the GMR sensor location and biasing of the GMR sensor to a location of high magnetic field sensitivity. In an alternate embodiment, a permanent magnet is positioned adjacent to the GMR sensor to accomplish the biasing. Experimental results have demonstrated identification of flaws up to 1 cm deep in aluminum alloy structures. To detect deep flaws about circular fasteners or inhomogeneities in thick multilayer conductive materials, the device is mounted in a hand-held rotating probe assembly that is connected to a computer for system control, data acquisition, processing and storage.
摘要翻译： 巨大的磁阻通量聚焦涡流装置有效地检测了厚层多层导电材料的深层缺陷。 探头使用激励线圈来引导垂直于线圈纵向轴线的材料中的涡流。 由激磁线圈包围的巨磁阻（GMR）传感器用于检测产生的场。 在励磁线圈和GMR传感器之间是一个高度透过的磁通聚焦透镜，它将GMR传感器和励磁线圈磁分离，并在GMR传感器的外缘产生高磁通密度。 使用通量聚焦透镜内的反馈能够完全消除GMR传感器位置处的泄漏场，并将GMR传感器偏置到高磁场灵敏度的位置。 在替代实施例中，永磁体被定位成与GMR传感器相邻以完成偏置。 实验结果表明，鉴定出铝合金结构深达1厘米深的缺陷。 为了检测厚多层导电材料中的圆形紧固件或不均匀性的深度缺陷，该装置安装在手持旋转探针组件中，该组件连接到计算机以进行系统控制，数据采集，处理和存储。
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公开(公告)号：US06190589B1
公开(公告)日：2001-02-20
申请号：US09504767
申请日：2000-02-11
IPC分类号： B29C318
CPC分类号： C08G73/1042 , H01F1/26 , H01F41/0246 , Y10T428/256 , Y10T428/31721
摘要： A molded magnetic article and fabrication method are provided. Particles of ferromagnetic material embedded in a polymer binder are molded under heat and pressure into a geometric shape. Each particle is an oblate spheroid having a radius-to-thickness aspect ratio approximately in the range of 15-30. Each oblate spheroid has flattened poles that are substantially in perpendicular alignment to a direction of the molding pressure throughout the geometric shape.
摘要翻译： 提供了一种成型的磁性制品和制造方法。 嵌入聚合物粘合剂中的铁磁材料的颗粒在热和压力下成型为几何形状。 每个颗粒是半径对厚度纵横比大约在15-30的范围内的扁圆球体。 每个扁圆球体具有平整的极，其基本上在整个几何形状中与成型压力的方向垂直对齐。
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公开(公告)号：US20120274319A1
公开(公告)日：2012-11-01
申请号：US13457687
申请日：2012-04-27
IPC分类号： G01R33/12
CPC分类号： G01R33/091 , G01R33/12
摘要： An eddy current probe includes an excitation coil for coupling to a low-frequency alternating current (AC) source. A magnetoresistive sensor is centrally disposed within and at one end of the excitation coil to thereby define a sensing end of the probe. A tubular flux-focusing lens is disposed between the excitation coil and the magnetoresistive sensor. An excitation wire is spaced apart from the magnetoresistive sensor in a plane that is perpendicular to the sensor's axis of sensitivity and such that, when the sensing end of the eddy current probe is positioned adjacent to the surface of a structure, the excitation wire is disposed between the magnetoresistive sensor and the surface of the structure. The excitation wire is coupled to a high-frequency AC source. The excitation coil and flux-focusing lens can be omitted when only surface inspection is required.
摘要翻译： 涡流探头包括用于耦合到低频交流（AC）源的激励线圈。 磁阻传感器居中设置在励磁线圈的一端内并在其一端，从而限定探头的感测端。 管状磁通聚焦透镜设置在励磁线圈和磁阻传感器之间。 励磁线在垂直于传感器的灵敏度轴的平面中与磁阻传感器间隔开，并且当涡流探针的感测端位于结构的表面附近时，激励线被布置 在磁阻传感器和结构的表面之间。 励磁线耦合到高频AC电源。 当仅需要表面检查时，可以省略励磁线圈和磁通聚焦透镜。
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公开(公告)号：US20100079157A1
公开(公告)日：2010-04-01
申请号：US12493573
申请日：2009-06-29
CPC分类号： G01N27/902 , G01N27/904
摘要： An eddy current system and method enables detection of sub-surface damage in a cylindrical object. The invention incorporates a dual frequency, orthogonally wound eddy current probe mounted on a stepper motor-controlled scanning system. The system is designed to inspect for outer surface damage from the interior of the cylindrical object.
摘要翻译： 涡流系统和方法能够检测圆柱形物体中的亚表面损伤。 本发明包括安装在步进电机控制扫描系统上的双频正交卷绕涡流探头。 该系统设计用于检查圆柱形物体内部的外表面损伤。
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