US4734577A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous strain measurement along a span
Assignee: Grumman Corp
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Filing: 1987-07-28
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Granted: 1988-03-29
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Expires: 2007-07-28
Abstract
Abstract A fiber optic load measuring system, and method of constructing the same, are disclosed which comprises a light source, a fiber optic attenuator, a photodetector, and a signal processor. The fiber optic attenuator was formed to have a curved portion along the length thereof disposed in low transfer relation with the surface where the load is to be measured. The signal processor is adapted to receive signals from the photodetector and measure variations attributable to the application of a load on the surface. The processor is further adapted to linearly translate the detected variations to compute deformation of the curved portion in response to an applied load.
Inventors
- 👤 Nicholas C. Szuchy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:06
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/16; G01B11/18; G01L; G01L1/00; G01L1/24; G01L1/242; G01L1/243; G01L1/245
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
189 words
A fiber optic load measuring system comprising: (a) an light source; (b) a fiber optic attenuator in optical communication with said light source, said attenuator having a selected thickness and formed to have at least one curved portion along the length thereof, said curved portion having a curve radius and a curve period, said curved portion being disposed in load transfer relation with a surface where the load is to be measured so that the curve radius and curve period are variable in response to an applied load, said curved portion being dimensioned so that light is attenuated in direct linear relation to deformation of said curved portion in response to an instantaneous applied load over a substantial range of applied load; (c) a photodetector in optical communication with said attenuator, said photodetector being operative to receive light signals reflected by said attenuator; and (d) a signal processor connected to said photodetector and operative to detect and measure reflected light signals attributable to the application of the instantaneous load on the surface, said processor being further operative to translate the reflected light signals to compute the instantaneous applied load.
Claim 2
Dependent Claim
189 words
A fiber optic load measuring system comprising: (a) an light source; (b) a fiber optic attenuator in optical communication with said light source, said attenuator having a selected thickness and formed to have at least one curved portion along the length thereof, said curved portion having a curve radius and a curve period, said curved portion being disposed in load transfer relation with a surface where the load is to be measured so that the curve radius and curve period are variable in response to an applied load, said curved portion being dimensioned so that light is attenuated in direct linear relation to deformation of said curved portion in response to an instantaneous applied load over a substantial range of applied load; (c) a photodetector in optical communication with said attenuator, said photodetector being operative to receive light signals reflected by said attenuator; and (d) a signal processor connected to said photodetector and operative to detect and measure reflected light signals attributable to the application of the instantaneous load on the surface, said processor being further operative to translate the reflected light signals to compute the instantaneous applied load.
Claim 3
Dependent Claim
17 words
The system as recited in claim 1 wherein said light source comprises a steady state light source.
Claim 4
Dependent Claim
16 words
The system as recited in claim 1 wherein said light source comprises a pulsed light source.
Claim 5
Dependent Claim
24 words
The system as recited in claim 1 further comprising an optical pulse delay element connected to said light source and said fiber optic attenuator.
Claim 6
Dependent Claim
48 words
The system as recited in claim 4 wherein said delay element comprises: (a) a spool; and (b) a predetermined length of optical material wound about said spool, said length of optical material being operative to delay light signals communicated between said light source and said fiber optic attenuator.
Claim 7
Dependent Claim
21 words
The system as recited in claim 1 wherein said fiber optic attenuator is formed to have a plurality of curved portions.
Claim 8
Dependent Claim
19 words
The system as recited in claim 1 wherein said fiber optic attenuator is formed to have a serpentine shape.
Claim 9
Dependent Claim
68 words
The system as recited in claim 1 wherein said fiber optic attenuator curved portion has a curve radius dimensioned so as to provide static attenuation of light passing therethrough, said curved portion also being dimensioned to provide variable dynamic attenuation of the light passing therethrough, said dynamic attenuation being linearly related to the instantaneous deformation of said curved portion in response to the load applied to the surface.
Claim 10
Dependent Claim
38 words
The system as recited in claim 1 wherein said attenuator curved portion has a curve radius dimensioned so as to attenuate the optical signal received from said optical signal generator in linear relation to the instantaneous applied load.
Claim 11
Dependent Claim
21 words
The system as recited in claim 1 wherein said attenuator is formed as an optical fiber of approximately 400 microns thickness.
Claim 12
Dependent Claim
21 words
The system as recited in claim 1 wherein said attenuator is formed as an optical fiber of approximately 600 microns thickness.
Claim 13
Dependent Claim
21 words
The system as recited in claim 1 wherein said attenuator is formed as an optical fiber of approximately 1000 microns thickness.
Claim 14
Dependent Claim
22 words
The system as recited in claim 1 wherein said attenuator is embedded in the surface where the load is to be measured.
Claim 15
Dependent Claim
22 words
The system as recited in claim 1 wherein said attenuator is disposed upon the surface where the load is to be measured.
Claim 16
Dependent Claim
22 words
The system as recited in claim 1 wherein said attenuator is formed as a circular optical fiber having a uniform refractive index.
Claim 17
Dependent Claim
32 words
The system as recited in claim 1 wherein said processor is operative to indicate the decay of the reflected return pulse as a function of distance along the length of said attenuator.
Claim 18
Dependent Claim
22 words
The system as recited in claim 1 wherein said processor is operative to determine the rate of change of the applied load.
Claim 19
Independent Claim
175 words
A method for measuring a load applied to a surface comprising: (a) bending an optical fiber having a selected thickness to form at least one curved portion along the length thereof said optical fiber being formed to have a curve radius and a curve period, said curve radius and said curve period being variable in response to an applied load, said curve radius and said fiber thickness being selected so light passing through said curved portion is attenuated in linear relation to the deformation of said curved portion in response to an instantaneous applied load over a substantial range of applied load; (b) disposing said optical fiber curved portion in load transfer relation to the surface where a load is to be applied; (c) communicating a light signal to the optical fiber curved portion; (d) receiving a return light signal reflected from said optical fiber curved portion; and (e) processing said return light signal to determine the load applied, said processing comprising linearly translating deviations in the return signal to determine the instantaneous applied load.
Claim 20
Independent Claim
175 words
A method for measuring a load applied to a surface comprising: (a) bending an optical fiber having a selected thickness to form at least one curved portion along the length thereof said optical fiber being formed to have a curve radius and a curve period, said curve radius and said curve period being variable in response to an applied load, said curve radius and said fiber thickness being selected so light passing through said curved portion is attenuated in linear relation to the deformation of said curved portion in response to an instantaneous applied load over a substantial range of applied load; (b) disposing said optical fiber curved portion in load transfer relation to the surface where a load is to be applied; (c) communicating a light signal to the optical fiber curved portion; (d) receiving a return light signal reflected from said optical fiber curved portion; and (e) processing said return light signal to determine the load applied, said processing comprising linearly translating deviations in the return signal to determine the instantaneous applied load.
Claim 21
Dependent Claim
26 words
The method as recited in claim 18 wherein said step of bending an optical fiber comprises the step of forming a serpentine shaped fiber optic attenuator.
Claim 22
Dependent Claim
26 words
The method as recited in claim 18 wherein said step of communicating a light signal comprises the step of generating a series of pulsed light signals.
Claim 23
Dependent Claim
26 words
The method as recited in claim 18 wherein said step of communicating a light signal comprises the step of generating a series of pulsed light signals.
Claim 24
Dependent Claim
21 words
The method as recited in claim 18 further comprising the step of delaying the light signal communicated to the optical fiber.
Claim 25
Dependent Claim
22 words
The method as recited in claim 22 further comprising the step of delaying the return light signal reflected from the optical fiber.
Claim 26
Dependent Claim
23 words
The method as recited in claim 18 further including the step of comparing deviations in the return signal over a period of time.
Claim 27
Dependent Claim
62 words
The method as recited in claim 18 wherein said step of bending an optical fiber comprises bending the optical fiber to form a curved portion, said curved portion being formed to have a curve radius dimensioned such that light passing therethrough is attenuated in linear relation to the deformation of said curved portion in response to the load applied to the surface.
Claim 28
Dependent Claim
53 words
The method as recited in claim 18 wherein said step of bending an optical fiber comprises bending the optical fiber to form a curved portion, said curved portion being formed to have a curve radius dimensioned such that light passing therethrough is attenuated in linear relation to the load applied to the surface.
Claim 29
Dependent Claim
84 words
The method as recited in claim 18 wherein said step of bending an optical fiber comprises bending the optical fiber to form a curved portion, said curved portion being formed to have a curve radius dimensioned so as to provide static attenuation of the light passing therethrough, said curved portion also being dimensioned to provide variable dynamic attenuation of light passing therethrough, said dynamic attenuation being linearly related to the deformation of said curved portion in response to the load applied to the surface.
Claim 30
Dependent Claim
25 words
The system as recited in claim 10 wherein said attenuator is formed to have a bend diameter of between one quarter and three quarter inches.
Claim 31
Dependent Claim
25 words
The system as recited in claim 11 wherein the attenuator is formed to have a bend diameter of between one eighth and one quarter inches.
Claim 32
Dependent Claim
28 words
The system as recited in claim 1 wherein said attenuator comprises a length of fiber optic material having at least one permanently curved portion along the length thereof.
Claim 33
Dependent Claim
34 words
The system as recited in claim 30 wherein said attenuator further comprises a substrate for supporting the length of fiber optic material, said substrate being in direct contact with and adhered to the surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |