AU598858B2 - Microbend fiber optic strain gauge - Google Patents
Microbend fiber optic strain gauge Download PDFInfo
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- AU598858B2 AU598858B2 AU78894/87A AU7889487A AU598858B2 AU 598858 B2 AU598858 B2 AU 598858B2 AU 78894/87 A AU78894/87 A AU 78894/87A AU 7889487 A AU7889487 A AU 7889487A AU 598858 B2 AU598858 B2 AU 598858B2
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- strain gauge
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
- G01L1/243—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre using means for applying force perpendicular to the fibre axis
- G01L1/245—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre using means for applying force perpendicular to the fibre axis using microbending
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/18—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge using photoelastic elements
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
Description
t 598 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION FOR OFFICE USE 858 Form Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: SOS0 .44~ A04 I t0or1eo ftr pr-ilo Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: THE BABCOCK WILCOX COMPANY 1010 Common Street, New Orleans, LOUISIANA 70160, U.S.A.
John W. Berthold and Stuart E. Reed GRIFFITH HASSEL FRAZER 71 YORK STREET SYDNEY NSW 2000
AUSTRALIA
Address for Service: Complete Specification for the invention entitled: MICROBEND FIBER OPTIC STRAIN GAUGE The following statement is a full description of this invention, including the best method of performing it known to me/us:- 2778A:rk I Case 4811 MIlI£EjyU i ElEEI fI£T1£ 5XIRAIlR fiAU-C: ELEL2 AInkl JA.QGXifM. Pi IQ E 101 £LWWI9 The present invention relates in general to strain gauges, and in particular to a new and useful microbend fiber optic strain gauge which utilizes a coated optical fiber held and bent between corrugated plates, and a reference optical fiber which is exposed to the same thermal condition but which is not hela between the corrugated plates.
aStrain gauges have been developed to measure 10 structural loads to verify proper design of both individual 0 0 0 o components and the overall structure. Strain gauges now o o include foil, thin film, or wire resistance devices which are bonded or welded to the test piece to be measured. Loads S applied to the test piece can cause it and the bonded gauge to extend, compress, or twist. The resulting strains induced in the gauge change its resistance. If the gauge resistor forms one leg of a Wheatatone bridge, the bridge will become unbalanced and a voltage developed in proportion to the amount of strain induced in the gauge. This approach is the basis of most strain gauge measurements performed today.
Difficulties are encountered when strain measurements j are to be made at elevated temperatures. For example, differential expansion between the gauge and test piece induces.strain in the gauge, using up a substantial portion of its range and masking the load-induced strain to be measured. Furthermore, for accurate and reliable measuremm-nt, resistance strain gauges are generally limited 1, t to temperatures below about 3150C (about 6000F). Above this temperature, physical and metallurgical effects such as alloy segregation, phase changes, selective oxidation and diffusion result in large non-repeatable and unpredictable changes in the gauge output, and often in premature failure of the gauge or leadwire system.
Currently, no satisfactory method exists to perform accurate and reliable strain measurement." at temperatures exceeding about 315 C. A reliable, stable strain gauge is needed that will work at these elevated temperatures and which will match the thermal expansion of the test piece to «o o" enable the gauge to be bonded at low temperatures.
0 0 00 0 o o0 o The measuremlent of the elongation of a structrual o o Smember such as a long strut, presents several problems 0 0 a o,5 similar to those encountered in strain ieasurement. In a relatively benign environment which is free of vibration, the °o elongation may be slowly varying with time. This situation o. requires that an elongation sensor be capable of essentially D.C. measurements. As a consequence the sensor must exhibit oO *20 extremely low drift.
This is further complicated when the structural member is in a hostile environment.
@S 0 O 0 4 SInstrumentation for in-flight monitoring of inlet and outlet engine conditions is needed for high-performance aircraft to improve fuel efficiency, engine performance, and overall reliability. This instrumentation must withstand the hostile engine environment which includes the high- 2 1~11 1-c i~ li-i--L1- ii.. I-IXL-l-.Ll~tLI. temperature operating conditions and vibrations. Optical fibers and optical sensing methods have been applied to a number of measurements in hostile environments including displacement, velocity, strain, flow, temperature, particle size distribution, gas composition and fluorescence. These optical sensing methods can also be used to measure pressure in the hostile environment.
Optical sensors can also be designed to operate at high temperatures and in regions of high electromagnetic fields.
SUMMARY OF THE INVENTION 00004 0000 0oo o 00 0 0 0 0..
ooa C) u n V 00 0 0 04 00 0.040 a .4 0 00 00 0 00 0 In a first aspect the present invention provides a strain gauge operable in hostile environments comprising: a pair of plates made of material having a temperature expansion coefficient similar to that of a material to be 15 tested in a high temperature environment and having facing corrugated surfaces with the corregations of one plate being offset with the corregations of the other plate and wherein at least one plate is attached to the material to be tested; a buffer coated first optical signal fiber clamped between the corrugations of the plates for being bent to a greater or lesser extent depending on pressure exerted on the plates for moving the plates together; a buffer coated reference optical signal fiber located in the vicinity of the plates so as to be simultaneously 25 exposed to the same thermal and other conditions along its length as the first optical fiber; optical signal applying means including a light source and light splitting means connected to one end of each optical fiber for simultaneously applying an optical signal to both optical fibers; and optical detector means connected to the opposite ends of both optical fibers for measuring the modulations in the optical signal transmitted through the first optical fiber which modulations correspond to pressures applied to the plates and for reading the modulations in the optical signal transmitted through the reference optical fiber.
In a second aspect the present invention provides a strain gauge operable in hostile environments, comprising: P"i~ LS0445s/as 044 5s/as -3a pair of plates made of material having a temperature expansion coefficient similar to that of the material to be tested in a high temperature environment of above about 315 0 C and having facing corrugated surfaces with the corregations of one plate being offset with the corregations of the other plate and wherein at least one plate is attached to the material to be tested; a buffer coated first optical signal fiber clamped between the corrugations of the plates for being bent to a greater or lesser extent depending on pressure exerted on the plates for moving the plates together; a buffer coated reference optical signal fiber located in the vicinity of the plates so as to be simultaneously exposed to the same thermal and other conditions along its 15 length as the first optical fiber; Soptical signal applying means including a light source and light splitting means connected to one end of each optical fiber for simultaneously applying an optical signal to both optical fibers; and i 20 optical detector means connected to the opposite ends I of both optical fibers for measuring the modulations in the optical signal transmitted through the first optical fiber which modulations correspond to pressure applied to the plates and for reading the modulations in the optical signal transmitted through the reference optical fiber.
In a third aspect the present invention provides a strain gauge operable in hostile environments comprising: a pair of plates made of material having a temperature expansion coefficient dissimilar to that of a material to be tested for the purpose of increasing the range of the sensor and having facing corrugated surfaces with the corregations of one plate being offset with the corregations of the other plate and wherein at least one plate is attached to the material to be tested; a buffer coated first optical signal fiber clamped between the corrugations of the plates for being bent to a greater or lesser extent depending on pressure exerted on the plates for moving the plates together; 0445s/as -4-
|T
a buffer coated reference optical signal fiber located in the vicinity of the plates so as to be simultaneoulsy exposed to the same thermal and other conditions along its length as the first optical fiber; optical signal applying means.including a light source and light splitting means connected to one end of each optical fiber for simultaneously applying an optical signal to both optical fibers; and optical detector means connected to the opposite ends of both optical fibers for measuring the modulations in the optical signal transmitted through the first optical fiber which modulations correspond to pressures applied to the plates and for reading the modulations in the optical signal transmitted through the reference optical fiber.
15 The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific results attained by its uses, 20 reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Fig. 1 is a side view in section showing the strain gauge of the present invention in its simplest form; Qq '0 000 00'n V 00r 00 0 0o 0 V 0 0 0D 0 01 o *i *4 a S6 I 0445s/as -4A- Fig. 2 is a block diagram showing the strain gauge of the present invention used with a reference fiber in addition to the signal fiber; I Fig. 3 is a graph plotting load versus displacement for the optical fiber of the invention with two spatial bends; Fig. 4 is a graph plotting the strain gauge output voltage versus displacement of the plates in the strain gauge; OoQijO Fig. 5 is a graph showing calibration of the O 00 microbend strain gauge of the present invention relative to a 0 0" reference gauge; and o 44 Fig. 6 is a side view in section showing the strain gauge of the present invention in a slot formed in the surfa.ce of a test piece whose strain is to be measured.
_EWlllJ~J2 LIllEil 1JHLEil A microbend fiber optic strain gauge 1 is diagrammed in Fig. 1. A glass-on-glass optical fiber 10 is used with the following nominal characteristics: Core diameter 125 um; Clad diameter 170 pm; Numerical aperture 0.2; Buffer coating 410 ni thick aluminum or polyimide; S 4 and Overall diameter 250 P~ri.
where 1 /in I- lo"' miCrs Fibers with the mentioned coatings are strong and rugged with tensile strengths exceeding 100,000 psi. The mierobend sensor is a light intensity sensor, and as such, uses simple opto-electronic components. The strain gauge comprises the above fiber 10 clamped between cortugated plates 12 and 141 made from material identical to that of a test piece. Changes in strain of the test piece change the plate separation and in turn the light intensity transmiitted ogo at the point of clamping. The corrugation spacing is about S3mm. Two corrugations 16 are on one platt 12 and three o 4 corrugations 18 are on the opposite plate 141 to provide two spatial sinusoidal bends in the fiber 10. The fiber is preloaded (bias compression) between the plates such that the peak-to-peak fiber bend amplitude is approximately 300 mn.
In this configuration the sensitivity and repeatability of a microbend sensor has been demonstrated to be .006 rpm. At these preloads the change in corrugated plate displacement with load is very nearly linear as shown in Fig. 3. Also note from Fig. 4 the microbend sensor linearity of output S signal versus displacement of the corrugated plates.
Performance data has been obtained on the microbend fiber optic strain gauge and is shown in Fig. 5. The i 25 microbend strain gauge was calibrated relative to a reference gauge. The microbend sensor plates 12 and 14 may .be attached 6 to the test piece in several different ways. These include welding or gluing the ends 21 and 22 to the surface of the test piece. A less obtrusive method would be to slot the surface and insert the plates into the slot. Fig. 6 shows a test piece 20 with slot 26 in which plates 12 and 14 are engaged. The plates are urged toward each other by their back surfaces 23 and 211. The method of attachment will be chosen to minimize alterations in the test piece structural properties and static and dynamic response.
Accelerated dynamic life tests have been performed on the microbend sensor and have demonstrated lifetime in excess of one million cycles with peak displacements of 25 im.
00 0 0 oo These tests were performed at 20kHlz cycling frequencies, which also demonstrated the high frequency response °l5 capability of the microbend sensor.
0 0 0 4 The microbend sensor uses inexpensive conventional o. opto-electronic components including a light emitting diode (LED), shown in Fig. 2 at 30, and silicon photodetector O By pulsing the LED and using CMOS integrated circuits to detect and amplify the photodetector signal, an average electronic power drain of less than 12 milliwatts per sensor has been demonstrated.
0 0 0 o o 1 As described previously and shown in Fib. 1, the microbend sensor may be preloaded by bias displacement of the plates so that the corrugations 16, 18 overlap by an amount greater than or equal to the fiber diameter or maximum expected elongation. When the plates are heated, the corrugation peak separation with temperature may be -j calculated. It,.is also straightforward to show that for each plate the change in peak-to-peak corrugation spacing with temperature has a negligible effect on the sensor output signal. It is anticipated in practice that the microbend corrugated plates can be properly aligned so that the corrugation peaks are within 13 pm of the desired preloaded displacement. In this case, the worst thermally induced elongation (ALr caused by positioning error is given by: (a L)T LO(AT 0 0 °Substituting for AT the required thermal operating 0 0o, range of 400 0 C, for O( a value of 8.5 x 10-6 t C for a typical Stitanium alloy, and for L the position error of 13 pm, the thermally induced elongation error is: (13)(8.5 x 10 (400) 0.011 pm.
Thus, for a gauge length of 1cm, the resulting thermally induced error is (4 strain, kreq lsLrqrp i/r/rn.
In addition to compensation of the thermo-mechnical Soffset just described, changes in optical fiber light transmission must be compensated as well as changes in light S source intensity and drift of photodetector output sensitivity. The invention has successfully compensated these changes using the approach diagrammed in Fig. 2. As shown in Fig. 2, second optical fiber 11 (reference fiber) is co-locatedswith the signal optical fiber 10 clamped between the corrugated plates (not shown in Fig. The reference optical fiber 11 is unclamped, but sees the same thermal ~'1 environment along its length as tile signal fiber.
A major advantage of the subject invention is that the microbend strain gauge allows the matching of the thermal expansion coefficient of the plate 12 and 14 with that of the substrate material to be tested. This cannot be done with conventional strain gauges, such as resistance strain gauges, and has the effect of 1) improving the range at temperature and 2) reducing the thermal output of the gauge.
The test data shown in Figures 3-5 were obtained using stainless steel plates. In general, the plate material r*a° would be chosen to match the thermal expansion coefficient of the underlying material. As an alternative, if the o 0* °o predominant strain direction is known, the thermal expansion coefficients of the plates and substrate can be initially 15 mismatched, biased against one another so as to increase the range of the strain gauge while maintaining the same sensitivity.
Plates 12 and 14 can also be made of fuzcd silica or other similar ceramics to increase resistance to thermal effects such as thermal degrading of the plates and the thermal expansion and contraction effect.
The advantages of the microbend fiber optic gauge of the invention are listed as follows: o o Operating temperatures above 427 C (800 F); Lightweight, compact and non-obtrusive, especially if the structural member is slotted to accept the corrugated 9 L-i-I-YI_ i_ i_
-~-LYI_
r i t_ *3 microbend sensor plates; Accuracy of 0.005 p u at frequencies from D.C. to The microbend sensor may be imechanically and electronically compensated with temperature, and electronics signal processing may be used to eliminate drift; Compatible with composite and metallic materials, this requirement being met by miaking the corrugated microbend sensor plates from material identical to the strut material or test piece; IImmune to electromagnetic interference and >oo electromagnetic pulse; °e 2 Since the sensor uses non-polarized light energy to "o operate, spark hazards are non-existent, and remote mounted 0 ;15 sensors are locatable in explosion hazard environments; and on Inert glass optical fiber material is resistant to corrosion.
o'S To increase the useful range of the present invention o o, up to about 540 C (about 1,000 a gold coated SiO z optical 0 0 a fiber can be utilized in place of the aluminum or polyimide o coated glass fiber. Both signal fiber 10 and reference fiber 11 can be constructed in this way. A strain gauge according to the invention and having this temperature resistance can S• be useful for long-term measurements of creep strains on &5 reheat or main steam lines in boilers.
Field installation of such gauges would be by capacitive discharge spot welding, thus requiring only local descaling and grinding for surface preparation.' Insulation which is normally used over pipes to be outfitted with the inventive strain gauge need only be removed in the immediate area of the gauge. A plug of iniclation which is, for example, two to three inches in diameter, could be removed, the gauge installed, and the plug replaced. The optical fiber leads would be brought out throught the insulation at the plug for connection to extension fibers and strain readout equipment.
Returning now to Fig. 2, both signal and reference fibers 10 and 11 are connected through known optical splices 42 to a fiber optic coupler '44.
oo The light output from LED 30 is split into two parts by the three dB coupler 44, and the now split output is S" coupled through splicers 42 to the signal fiber 10 and the reference fiber 11. These multimode optical fibers then supply their output signals to the dual photodetector 40 and its associated output circuitry 46. Signals A and B are digitized and converted in converter circuit 46 to form values for the compensated sensor signal.
,O While specific embodiments of the invention have been 1 1 shown and described in detail to illustrate the application of the principles of the invention, it will be understood Sthat the invention may be embodied otherwise without departing from such principles.
Claims (4)
- 9.9 9 C9 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: i. A strain gauge operable in hostile environments comprising: a pair of plates made of material having a temperature expansion coefficient similar to that of a material to be tested in a high temperature environment and having facing corrugated surfaces with the corregations of one plate being offset with the corregations of the other plate and wherein at least one plate is attached to the material to be tested; a buffer coated first optical signal fiber clamped between the corrugations of the plates for being bent to a greater or lesser extent depending on pressure exerted on the plates for moving the plates together; a buffer coated reference optical signal fiber located 15 in the vicinity of the plates so as to be simultaneously exposed to the same thermal and other conditions along its length as the first optical fiber; optical signal applying means including a light source and light splitting means connected to one end of each optical fiber for simultaneously applying an optical signal to both optical fibers; and optical detector means connected to the opposite ends of both optical fibers for measuring the modulations in the optical signal transmitted through the first optical fiber which modulations correspond to pressures applied to the plates and for reading the modulations in the optical signal transmitted through the reference optical fiber. 2. A strain gauge according to claim i, wherein said signal and reference fibers have a glass core and cladding and an aluminum coating. 3. A strain gauge according to claim i, wherein said signal and reference fibers have a glass core and cladding and a polyimide coating. 4. A strain gauge according to claim I, wherein said signal and reference fibers have a core of SiO 2 and a coating of gold. 5. A strain gauge operable in hostile environments, 94 6 a 4 4 449 900 T, A 1-f LS j CNT comprising: 0445s/as -12- V J a pair of plates made of material having a temperature expansion coefficient similar to that of the material to be tested in a high temperature environment of above about 315 0 C and having lacing corrugated surfaces with corregations of one plate being offset with the corregations of the other plate and wherein at least one plate is attached to the material to be tested; a buffer coated first optical signal fiber clamped between the corrugations of the plates for being bent to a greater or lesser extent depending on pressure exerted on the plates for moving the plates together; a buffer coated reference optical signal fiber located in the vicinity of the plates so as to be simultaneously eo exposed to the same thermal and other conditions along its 15 length as the first optical fiber; 0o0 0 optical signal applying means including a light source 0o oand light splitting means connected to one end of each o optical fiber for simultaneously applying an optical signal p00 00,to both optical fibers; and o optical detector means connected to the opposite ends of both optical fibers for measuring the modulations in the optical signal transmitted through the first optical fiber which modulations correspond to pressure applied to the plates and for reading the modulations in the optical signal transmitted through the reference optical fiber. 6. A strain gauge according to claim 5, wherein said signal and reference fibers have a glass core and cladding and an aluminum coating. 7. A strain gauge according to claim 5, wherein said signal and reference fibers have a glass core and cladding and a polyimide coating. 8. A strain gauge according to claim 5, wherein said signal and reference fibers have core of SiO 2 and a coating of gold. 9. A strain gauge operable in hostile environments comprising: L a pair of plates made of material having a temperature expansion coefficient dissimilar to that of a material to be /I~ 0445s/as -13- 040C, 0 0 CI 0) 0~ 0 0 00 0 00 00 0 0 00 00 000 tested for the purpose of increasing the range of the sensor and having facing corrugated surfaces with the corregations of one plate being offset with the corregations of the other plate and wherein at least one plate is attached to the material to be te-ted; a buffer coated first optical signal fiber clamped between the corrugations of the plates for being bent to a greater or lesser extent depending on pressure exerted on the plates for moving the plates together; a buffer coated reference optical signal fiber located in the vicinity of the plates so as to be simultaneoulsy exposed to the same thermal and other conditions along its length as the first optical fiber; optical signal applying means including a light source 15 and light splitting means connected to one end of each optical fiber for simultaneously applying an optical signal to both optical fibers; and optical detector means connected to the opposite ends of both optical fibers for measuring the modulations in the optical signal transmitted through the first optical fiber which modulations correspond to pressures applied to the plates and for reading the modulations in the optical signal transmitted through the reference optical fiber. A strain gauge according to claim 9, wherein said signal and reference fibers have a glass core and cladding and an aluminum coating.
- 11. A strain gauge according to claim 9, wherein said signal and reference fibers have a glass core and cladding and a polyimide coating.
- 12. A strain gauge according to claim 9, wherein said signal and reference fibers have a core of SiO 2 and a coating of gold.
- 13. A strain gauge substantially as hereinbefore described with reference to the accompanying drawings. L K:d~i is~ DATED this 16th day of January, 1990 THE BABCOCK WILCOX COMPANY By their Patent Attorneys GRIFFITH HACK CO. 0445s/as -14-
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US92496286A | 1986-10-30 | 1986-10-30 | |
| US924962 | 1986-10-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU7889487A AU7889487A (en) | 1988-05-05 |
| AU598858B2 true AU598858B2 (en) | 1990-07-05 |
Family
ID=25450986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU78894/87A Ceased AU598858B2 (en) | 1986-10-30 | 1987-09-23 | Microbend fiber optic strain gauge |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS63117205A (en) |
| CN (1) | CN1016100B (en) |
| AU (1) | AU598858B2 (en) |
| CA (1) | CA1299389C (en) |
| GB (1) | GB2196735B (en) |
| IN (1) | IN167564B (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2650670A1 (en) * | 1989-08-02 | 1991-02-08 | Fiori Costantino | System for detecting a fire or any other phenomenon generating an abnormal rise or fall in temperature with respect to a fixed reference |
| US5039218A (en) * | 1990-03-28 | 1991-08-13 | Hughes Aircraft Company | Testing of optical fiber by introducing multiple simulated peel location bends |
| GB2250813A (en) * | 1990-12-15 | 1992-06-17 | British Aerospace | Weighing apparatus for vehicles |
| WO1996017223A1 (en) * | 1994-11-29 | 1996-06-06 | United Technologies Corporation | Optical fiber bragg grating coating removal detection |
| PL1709416T3 (en) | 2004-01-23 | 2018-08-31 | Lm Wind Power International Technology Ii Aps | Device including a system adapted for use in temperature compensation of strain measurements in fibre-reinforced structures |
| CN1300571C (en) * | 2004-08-24 | 2007-02-14 | 西安科技大学 | Snake type fiber-optical sensor burying and detecting method and its snake type fibre-optical sensor |
| CN101881633B (en) * | 2010-04-06 | 2012-11-28 | 西安金和光学科技有限公司 | Spring type high-precision optical fiber sensor based on optical fiber bending loss |
| CN102221374B (en) * | 2010-04-19 | 2015-07-15 | 西安金和光学科技有限公司 | Fiber sensing device for sensing torque parameters |
| WO2012010099A1 (en) * | 2010-07-21 | 2012-01-26 | 西安金和光学科技有限公司 | Optic fiber cylinder sensor |
| CN102829901A (en) * | 2011-06-14 | 2012-12-19 | 西安金和光学科技有限公司 | Optical fiber sensing device waveform grooves and cylinder body |
| EP2962080B1 (en) * | 2013-02-28 | 2021-05-19 | Osmos Group | Optical measurement device having a reference channel and a measurement channel, and related method |
| CN103604540B (en) * | 2013-11-13 | 2015-06-10 | 中铁四局集团第一工程有限公司 | Photoelectric stressometer |
| CN104359653B (en) * | 2014-10-23 | 2015-08-12 | 河海大学 | A kind of optical fiber single-direction and dual-direction bending curvature binary channels tracking and monitoring instrument and monitoring method |
| CN105606276B (en) * | 2015-12-24 | 2018-06-12 | 中北大学 | MEMS optical fiber micro-bending pressure sensors and preparation method thereof |
| CN106441661A (en) * | 2016-12-02 | 2017-02-22 | 西南交通大学 | Fiber grating force-measuring gasket and anchor rod force-measuring system |
| EP3578937A1 (en) * | 2017-02-02 | 2019-12-11 | Fujikura Ltd. | Photodetector and method for manufacturing photodetector |
| CN109620186A (en) * | 2019-01-30 | 2019-04-16 | 福州新易达光电科技有限公司 | A kind of optical fiber micro-bending sensor for monitoring human vital sign parameter |
| GB2586974B (en) * | 2019-09-06 | 2022-12-28 | Nuron Ltd | System for producing strain in a fibre |
| CN111707206B (en) * | 2020-06-04 | 2022-03-18 | 哈尔滨工程大学 | Quantum dot optical fiber micro-bending sensor with position detection function |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU6317886A (en) * | 1986-02-03 | 1987-08-06 | International Control Automation Finance Sa | Overload protection for fiber optic microbend sensor |
| AU1217788A (en) * | 1987-02-26 | 1988-09-01 | Bicc Public Limited Company | Optical fibre sensor using microbending to detect a variable |
| AU579041B2 (en) * | 1986-05-09 | 1988-11-10 | Thomas & Betts Corporation | Method of and apparatus for fiber optic sensing |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0027540A3 (en) * | 1979-09-11 | 1981-10-07 | Hydroacoustics Inc. | Optical sensor and transducer array system |
| US4436995A (en) * | 1981-06-29 | 1984-03-13 | General Electric Company | Fiber optics transducers for sensing parameter magnitude |
| GB2125161A (en) * | 1982-07-21 | 1984-02-29 | Gen Electric Co Plc | Optical fibre sensors |
| JPS5946805A (en) * | 1982-09-11 | 1984-03-16 | Diesel Kiki Co Ltd | Displacement detector |
-
1987
- 1987-08-17 CA CA000544687A patent/CA1299389C/en not_active Expired - Fee Related
- 1987-08-17 IN IN645/CAL/87A patent/IN167564B/en unknown
- 1987-08-17 GB GB8719390A patent/GB2196735B/en not_active Expired - Fee Related
- 1987-09-23 AU AU78894/87A patent/AU598858B2/en not_active Ceased
- 1987-10-29 CN CN 87107210 patent/CN1016100B/en not_active Expired
- 1987-10-29 JP JP27198387A patent/JPS63117205A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU6317886A (en) * | 1986-02-03 | 1987-08-06 | International Control Automation Finance Sa | Overload protection for fiber optic microbend sensor |
| AU579041B2 (en) * | 1986-05-09 | 1988-11-10 | Thomas & Betts Corporation | Method of and apparatus for fiber optic sensing |
| AU1217788A (en) * | 1987-02-26 | 1988-09-01 | Bicc Public Limited Company | Optical fibre sensor using microbending to detect a variable |
Also Published As
| Publication number | Publication date |
|---|---|
| AU7889487A (en) | 1988-05-05 |
| GB2196735A (en) | 1988-05-05 |
| GB2196735B (en) | 1991-01-23 |
| CA1299389C (en) | 1992-04-28 |
| IN167564B (en) | 1990-11-17 |
| CN1016100B (en) | 1992-04-01 |
| GB8719390D0 (en) | 1987-09-23 |
| JPS63117205A (en) | 1988-05-21 |
| CN87107210A (en) | 1988-08-03 |
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