Surface mounted and scanning spatially periodic eddy-current sensor arrays
First Claim
1. A method of monitoring damage at a fastener through the test substrate comprising:
- mounting respective spatially periodic field eddy-current sensors to the test substrate at both ends of a fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensors.
1 Assignment
0 Petitions
Accused Products
Abstract
Inductive sensors measure the near surface properties of conducting and magnetic material. A sensor may have primary windings with parallel extended winding segments to impose a spatially periodic magnetic field in a test material. Those extended portions may be formed by adjacent portions of individual drive coils. Sensing elements provided every other half wavelength may be connected together in series while the sensing elements in adjacent half wavelengths are spatially offset. Certain sensors include circular segments which create a circularly symmetric magnetic field that is periodic in the radial direction. Such sensors are particularly adapted to surround fasteners to detect cracks and can be mounted beneath a fastener head. In another sensor, sensing windings are offset along the length of parallel winding segments to provide material measurements over different locations when the circuit is scanned over the test material. The distance from the sensing elements to the ends of the primary winding may be kept constant as the offset space in between sensing elements is varied. An image of the material properties can be provided as the sensor is scanned across the material.
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Citations
58 Claims
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1. A method of monitoring damage at a fastener through the test substrate comprising:
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mounting respective spatially periodic field eddy-current sensors to the test substrate at both ends of a fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensors. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for monitoring damage at a fastener comprising:
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mounting at least two eddy-current sensor arrays on a test substrate around respective fasteners;
connecting drive and sense conductors of the eddy-current sensors with a single cable to a data acquisition system; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensors. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 58)
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18. A method for monitoring damage at a fastener comprising:
mounting a spatially periodic field eddy-current sensor array to a test substrate under the head of a fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array.- View Dependent Claims (19, 20, 21)
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22. A method for performing fatigue testing at a fastener comprising:
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mounting an eddy current sensor array to a test substrate under the head of a fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array. - View Dependent Claims (23, 24)
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25. A method of monitoring damage at a fastener comprising:
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mounting a spatially periodic field eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener, and sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array. - View Dependent Claims (26)
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27. A method of monitoring damage at a fastener comprising:
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mounting a spatially periodic field eddy-current sensor array to a test specimen, the sensor being mounted between layers of the test coupon attached by the fastener; and
sensing response of the test specimen to a magnetic field imposed by the eddy-current sensor array. - View Dependent Claims (28, 29, 30)
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31. A method for performing fatigue testing at a fastener comprising:
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mounting an eddy current sensor array to a test substrate under the head of a fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array.
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32. A method of monitoring damage at a fastener comprising:
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mounting a spatially periodic field eddy-current sensor array to a structure near a fastener, the sensor array being mounted between layers of the structure attached by the fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array, each eddy-current sensor having at least two drive conductors and the current changing direction in at least one conductor.
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33. A method of monitoring damage at a fastener comprising:
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mounting a spatially periodic field eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener;
sensing response of the structure to a magnetic field imposed by the eddy-current sensor; and
calibrating each sense element of the eddy-current sensor array by adjusting the response to an appropriate level. - View Dependent Claims (34, 35, 36)
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37. A method of monitoring damage at a fastener comprising:
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mounting a spatially periodic field eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener; and
sensing response of the structure to a magnetic field imposed by the eddy-current sensor array, each eddy current sensor having a periodic magnetic field produced by linear segments of its drive winding.
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38. A method of monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener; and
sensing response of the structure to a magnetic field imposed by the eddy-current sensor array, the sensor array having a magnetic field produced by a drive winding formed from concentric conductors within the same plane. - View Dependent Claims (39)
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40. A method for monitoring damage at a fastener comprising:
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mounting a spatially periodic field eddy current sensor array with a cylindrical support material shaped in the form of a washer;
mounting the cylindrical support to a test substrate under a fastener head; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor. - View Dependent Claims (41)
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42. A method for monitoring damage under the head of a fastener comprising:
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mounting an eddy current sensor array to a test substrate under the head of a fastener with sense elements located at different radial distances from the fastener center; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensors.
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43. A method for monitoring damage under the head of a fastener comprising:
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mounting an eddy current sensor array to a test substrate under the head of a fastener with sense elements located at different circumferential positions around the fastener; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensors.
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44. A method of monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener with at least one sensing element placed in an area likely to see damage and at least one sensing element placed in an area unlikely to see damage; and
sensing response of the structure to a magnetic field imposed by the eddy-current sensors.
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45. A method of monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener with sense elements located at different radial distances from the fastener center; and
sensing response of the structure to a magnetic field imposed by the eddy-current sensors.
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46. A method of monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array to a structure near a fastener, the sensor being mounted between layers of the structure attached by the fastener with sense elements located at different circumferential positions around the fastener; and
sensing response of the structure to a magnetic field imposed by the eddy-current sensors.
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47. A method for monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array with a cylindrical support material shaped in the form of a washer with at least one sensing element placed in an area likely to see damage and at least one sensing element placed in an area unlikely to see damage;
mounting the cylindrical support to a test substrate under a fastener head; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array.
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48. A method for monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array with a cylindrical support material shaped in the form of a washer the sense elements being located at different radial distances from the fastener center;
mounting the cylindrical support to a test substrate under a fastener head; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array.
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49. A method for monitoring damage at a fastener comprising:
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mounting an eddy-current sensor array with a cylindrical support material shaped in the form of a washer the sense elements being located at different circumferential positions around the fastener;
mounting the cylindrical support to a test substrate under a fastener head; and
sensing response of the test substrate to a magnetic field imposed by the eddy-current sensor array.
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50. A method for monitoring damage at a fastener comprising:
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mounting at least two eddy-current sensor arrays on a test substrate around fasteners;
connecting drive windings of the eddy-current sensor arrays in series; and
sensing a response of the test substrate to a magnetic field imposed by the eddy-current sensor arrays. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57)
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Specification