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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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公开(公告)号：US5493511A
公开(公告)日：1996-02-20
申请号：US988084
申请日：1992-12-08
CPC分类号： B06B1/045 , G01H11/02 , G01N29/12 , G01N29/2412 , G01N2203/0062 , G01N2291/014 , G01N2291/0237 , G01N2291/0258 , G01N2291/0427 , G01N2291/105
摘要： A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries.
摘要翻译： 提供了一种非破坏性地检测薄金属板中的裂纹长度和裂缝几何形状的装置和方法。 非接触式振动装置产生共振振动而不引入外来噪声。 裂纹板中产生的共振振动偏移与具有类似共振振动位移的板中已知的裂纹长度相关。 此外，谐振频率处的裂纹的声发射与已知裂纹几何形状的声发射相关。
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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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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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7.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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