Fastener and fitting based sensing methods
First Claim
1. A method for monitoring a test material around a fastener comprising:
- mounting a fastener into a test material, the fastener having integrated conductors;
driving the conductors with an electric signal to create an interrogating field within the test material; and
measuring a response with at least one other conductor to measure the test material.
1 Assignment
0 Petitions
Accused Products
Abstract
Damage and usage conditions in the vicinity of fasteners in joined structures are nondestructively evaluated using the fasteners themselves. Sensors or sensor conductors are embedded in the fasteners or integrated within the fastener construct, either in the clearance gap between the fastener and the structure material or as an insert inside the shaft or pin of the fastener. The response of the material to an interrogating magnetic or electric field is then measured with drive and sense electrodes both incorporated into the fastener or with either drive or sense electrodes external to the fastener on the material surface. In another configuration, an electric current is applied to one or more fasteners and the electric potential is measured at locations typically between the driven electrodes applying the current. The potential is measured circumferentially around the fastener at locations on the material surface or across pairs of fasteners throughout or along the joint. The voltage or potential measurement electrodes may be collinear with the drive electrodes. State sensitive material layers can be added either to the fastener or the test material layers in order to enhance observability of the test material condition, such as the presence of a crack, mechanical stress, delamination, or disbond.
71 Citations
47 Claims
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1. A method for monitoring a test material around a fastener comprising:
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mounting a fastener into a test material, the fastener having integrated conductors;
driving the conductors with an electric signal to create an interrogating field within the test material; and
measuring a response with at least one other conductor to measure the test material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10)
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8. The method as claimed in claim I wherein the fastener further comprises an indicator layer that enhances sensitivity to the test material condition.
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11. A method for monitoring a test material around a fastener comprising:
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providing a test material containing a fastener;
applying an electrical current between the fastener and a location remote from the fastener; and
measuring a voltage response. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for detecting the state of a test material comprising:
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mounting a fastener within a test material, the fastener including an integrated drive conductor;
driving the conductor with a current to produce a magnetic field that induces eddy-currents in the test material;
locating a sense conductor near the test material;
measuring a response of the sense conductor to the magnetic field; and
using the response to determine a state of the test material. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification