Fiber optic stress sensor for structural joints
First Claim
1. A method for monitoring the structural integrity of a joint between a first substantially rigid structural member and a second substantially rigid structural member, said first structural member having a first surface and said second structural member having a second surface substantially parallel to said first surface, said joint having an adhesive between said surfaces for joining said structural members, comprising the steps of:
- disposing a portion of an optical fiber between said surfaces and embedded in said adhesive, said fiber not penetrating said surfaces, said fiber having an end;
injecting an optical signal into said end of said optical fiber;
detecting a reflection of said optical signal at said end of said fiber, said reflection having a transit time; and
providing a strain detection signal in response to said detection of said reflection.
3 Assignments
0 Petitions
Accused Products
Abstract
A system for monitoring strain in structural joints has one or more opticalibers embedded in the joint between the structural members. The joint may be fastened using fasteners such as rivets or bonded using an adhesive. Strain on the joined members is transmitted to the fiber, deforming it. An optical reflectometer connected to one end of the fiber injects an optical signal into the fiber and detects the reflection of the signal. The time period between injection of the signal and detection of the reflection is used to localize the area of stress along the fiber.
39 Citations
13 Claims
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1. A method for monitoring the structural integrity of a joint between a first substantially rigid structural member and a second substantially rigid structural member, said first structural member having a first surface and said second structural member having a second surface substantially parallel to said first surface, said joint having an adhesive between said surfaces for joining said structural members, comprising the steps of:
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disposing a portion of an optical fiber between said surfaces and embedded in said adhesive, said fiber not penetrating said surfaces, said fiber having an end; injecting an optical signal into said end of said optical fiber; detecting a reflection of said optical signal at said end of said fiber, said reflection having a transit time; and providing a strain detection signal in response to said detection of said reflection. - View Dependent Claims (2, 3, 4, 5)
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6. A method for monitoring the structural integrity of a joint between a first substantially rigid structural member and a second substantially rigid structural member, said first structural member having a first surface and said second structural member having a second surface substantially parallel to said first surface, said joint having at least one fastener for connecting said structural members, comprising the steps of:
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disposing an optical fiber between said surfaces and adjacent to said fastener, said fiber not penetrating said surfaces, said fiber having an end; injecting an optical signal into said end of said fiber; detecting a reflection of said optical signal at said end of said fiber, said reflection having a transit time; and providing a strain detection signal in response to said detection of said reflection. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method for monitoring the structural integrity of a joint, comprising the steps of:
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forming a composite member having an embedded optical fiber; forming an adhesive bond between said composite member having said loop and a second composite member, said bond adjacent to a portion of said fiber; injecting an optical signal into said fiber; detecting a reflection of said optical signal, said reflection having a transit time; and providing a strain detection signal in response to said detection of said reflection. - View Dependent Claims (13)
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Specification