GB2058394A - Pressure-sensitive Optical Fibre Cable - Google Patents

Pressure-sensitive Optical Fibre Cable Download PDF

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Publication number
GB2058394A
GB2058394A GB8027454A GB8027454A GB2058394A GB 2058394 A GB2058394 A GB 2058394A GB 8027454 A GB8027454 A GB 8027454A GB 8027454 A GB8027454 A GB 8027454A GB 2058394 A GB2058394 A GB 2058394A
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United Kingdom
Prior art keywords
cable
optical fibre
cable according
module
fibre
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8027454A
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GB2058394B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Electronics Ltd
Original Assignee
Marconi Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Marconi Co Ltd filed Critical Marconi Co Ltd
Priority to GB8027454A priority Critical patent/GB2058394B/en
Publication of GB2058394A publication Critical patent/GB2058394A/en
Application granted granted Critical
Publication of GB2058394B publication Critical patent/GB2058394B/en
Expired legal-status Critical Current

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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
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/02—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for weighing wheeled or rolling bodies, e.g. vehicles
    • G01G19/022—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for weighing wheeled or rolling bodies, e.g. vehicles for weighing wheeled or rolling bodies in motion
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
    • G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
    • G01G3/125—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing wherein the weighing element is an optical member
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/64—Devices characterised by the determination of the time taken to traverse a fixed distance
    • G01P3/68—Devices characterised by the determination of the time taken to traverse a fixed distance using optical means, i.e. using infrared, visible, or ultraviolet light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4415—Cables for special applications
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/04—Detecting movement of traffic to be counted or controlled using optical or ultrasonic detectors

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Light Guides In General And Applications Therefor (AREA)

Abstract

An optical fibre cable suitable for pressure sensing, for example for detecting the passage of a moving vehicle and its speed or weight, comprises one or more optical fibre modules each consisting of a vitreous optical fibre coated with a resilient buffering layer of polymeric material such as silicone resin, and possibly an additional buffering layer of nylon or polyester, one or more strands of deformable filamentary material laid straight along or helically wound around the buffered fibre, and a protective sleeve of abrasion-resistant material extruded over the winding. Pressure applied to the cable deforms the sleeve and is transmitted locally by the winding to the fibre, causing attenuation of light propagated along the fibre to sensing means. The winding may consist of aromatic polyamide yarns, glass filaments, nylon filaments or cord, or fine copper wire. The sleeve may be of polyester, polyethylene, polyvinyl chloride, or natural or synthetic rubber. The module or cable may have an outer polyethylene jacket.

Description

SPECIFICATION Optical Fibre Cables and Fibric Optic Pressure Sensing Systems This invention relates to optical fibre cables, the object of the invention being the provision of an optical fibre cable of such construction that it is suitable for use for sensing the application of pressure to the cable, for example by a moving vehicle passing over the cable. The invention also relates to pressure sensing systems incorporating optical fibre cables of the form described.
According to the invention, an optical fibre cable suitable for use for pressure sensing is formed of one or more optical fibre modules each of which consists of or includes a single vitreous optical fibre coated with a resilient buffer layer of polymeric material having an elastic modulus not greater than 10 megapascals, one or more strands of deformable filamentary material having an elastic modulus higher than that of the buffering layer, laid on the surface of the buffered fibre, and a protective sleeve of abrasion-resistant material having an elastic modulus of less than 5 gigapascals, extruded over the filamentary material.
A pressure sensing system in accordance with the invention includes an optical fibre cable of the form described above, laid in a location in which at least part of the length of the cable will be subjected to applied pressure, a light source arranged to launch light into an end of the optical fibre, or of each optical fibre, incorporated in the cable, and sensing means arranged to receive light emitted from an end or ends of the optical fibre or fibres and to detect and indicate a reduction in the intensity of said emitted light resulting from the application of pressure to the cable or to one or more portions of the length thereof.
It will be understood that the term "light", as used herein, means any form of electromagnetic radiation which is capable of being transmitted along an optical fibre.
The application of pressure to a portion of the optical cable causes deformation of the protective sleeve, the filamentary strand or strands and the buffering layer of each optical fibre module in that portion of the cable, and the pressure is transmitted locally by the filamentary strand or strands, through the buffering layer, to the optical fibre, thus producing microbending or other deformation of the fibre, which results in attenuation of the light propagating along the fibre and received by the sensing means.Usually the filaments and the protective sleeve, as well as the buffer layer, are formed of resilient material, so that on release of the pressure all these components rapidly return to their original shape, the deformation of the optical fibre is substantially eradicated, and the light emission from the output end of the fibre is restored substantially to its initial intensity. However, if it is desired to retain a permanent record of the light attenuation produced by the pressure, the filaments may be formed of non-resilient material which is permanently set after deformation, for example fine wire of a ductile metal such as copper.
A pressure sensing system which is operated by the transmission of optical signals along an optical fibre cable in accordance with the invention is advantageous in that a fast response is obtained to the application of pressure to any part of the cable. Additionai advantages are that the cable can be, and preferably is, of wholly dielectric construction, metals being excluded (unless metal filaments as mentioned above are required), and that the cable can be of such small diameter that when suitably located it may be virtually undetectable.
The optical fibres employed in the cables of the invention are suitably composed of vitreous silica with one or more dopants for modifying the refractive index of the silica to give a fibre having either a step index profile or a graded index profile. Alternatively, the fibres may consist of a vitreous core with a cladding of polymeric material: in this case the polymer cladding may itself constitute at least part of the buffering layer of the optical fibre module. The fibres may be of either the monomode or multimode type.
The buffer coating on the optical fibre preferably consists of a silicone resin, but any other resin with a suitably low elastic modulus may be used. The coating is preferably applied in liquid form to the fibre immediately after the latter has been drawn, the liquid coating then being cured. If desired, an additional buffering layer of, for example, amorphous nylon, or a meltprocessable polyester such as the material sold under the Registered Trade Mark "Hytrel", may be applied by extrusion over the first soft buffer coating, the filamentary strand or strands being laid on the surface of the additional buffering layer.
Suitable resilient filamentary materials for use for applying on the surface of the buffered optical fibre include, for example, aromatic polyamide yarns, glass filaments, and nylon filaments or cord. One or more filaments, yarns or cords may be laid straight along the surface of the buffered fibre, so as to lie substantially parallel to the optical fibre, but preferably the strand or strands of filamentary material is or are helically wound around the buffered fibre. Windings of yarns or individual filaments preferably cover the buffer coating completely, and may consist of a single layer of filaments wound with a very short pitch, or of several layers of filaments. The filament assembly may, if desired, be impregnated with resin to produce a more rigid and robust module.
If the winding is in the form of cord, it need not cover the whole of the buffer surface, but may be wound with a longer pitch, suitably not exceeding 50 millimetres.
The extruded protective sleeve, which may fit either tightly or loosely over the filamentary strand or strands, is primarily for the protection of the filamentary material, the buffer layer or layers and the optical fibre against damage, and contributes little to the transmission of pressure to the fibre. Preferably the elastic modulus of the sleeve material is less than one gigapascal, suitable materials being, for example, "Hytrel", polyethylene, polyvinyl chloride, and naturai and synthetic rubbers. Harder material such as polyurethane resin may be employed if the cable is to be used in arduous conditions, but this might reduce the sensitivity of the module to applied pressure. If desired, an outer jacket of synthetic resin, for example polyethylene, may be extruded over the sleeve, to provide additional protection, but this again would reduce the sensitivity of the module.
An optical fibre cable in accordance with the invention may be constituted by a single optical fibre module of the form described, with or without an outer jacket, or may be composed of two or more such modules, either laid straight and parallel or helically intertwisted. An assembly of two or more modules may be enclosed in an outer jacket of synthetic resin, which should be formed of material having a fairly low elastic modulus, such as polyethylene.
Some specific forms of optical fibre module suitable for use as, or for inciusion in, a cable in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which Figures 1, 2 and 3 respectively show, in elevation, with parts removed to reveal the structure, three different forms of module.
Figure 1 shows a module consisting of an optical fibre 1, composed of doped vitreous silica and of 120 microns diameter, coated with a buffering layer 2 of silicone resin, a single layer of "Kevlar" aromatic polyamide yarn 3 ("Kevlar" is a Registered Trade Mark) helically wound around the silicone layer so as to completely cover the surface thereof, and a tightly fitting sleeve 4 of "Hytrel" extruded over the "Kevlar" winding. The overall external diameter of the module is 0.8 mm.
In the module shown in Figure 2, the silica fibre 1 and buffer coating of silicone 2, which are similar to those of Figure 1, are covered with an additional buffering layer consisting of a tightly fitting extruded tube of "Hytrel", 5, of external diameter 0.5 mm.
This tube is overwound with nylon cord 6 of diameter approximately 0.8 mm, with a pitch of 5 mm, and a single yarn of "Kevlar", 7, for holding the nylon cord in position. This assembly is enclosed in a loosely fitting extruded polyethylene sleeve 8, partly shown in section: the sleeve has an external diameter of 4 mm and an internal diameter of 2.2 mm.
The module shown in Figure 3 consists of an optical fibre 1 and silicone buffering layer 2, similar to those of Figure 1, a winding 9 consisting of three layers of "Kevlar" yarn, a tightly fitting extruded "Hytrel" sleeve 10 of external diameter 1.2 mm, and a tightly fitting extruded outer jacket 11 of polyethylene, of external diameter 2.2 mm.
In use of the pressure sensing system of the invention, the light emission from the optical fibre or fibres is monitored by the sensing means, which includes means for converting variations in the light intensity into a suitable form of signal for recording or display, may include means for amplifying the signals if necessary, and may be calibrated to indicate the relationship between the degree of attenuation of the light and the magnitude of the load producing it. The duration and repetition rate of the attenuation signals may also be shown, for example as a wave-form display.
The pressure sensing system is usually employed for sensing localised pressure applied to one or more short lengths of the cable, but may also be used for sensing pressure applied to the whole length of the cable. Thus the system can be employed for detecting the presence of moving road vehicles or railway trains, the cable being laid on a road surface or, in the case of a railway, partially embedded in a sleeper, so that the vehicle wheels or tracks, or the train wheels, apply local pressure as they pass transversely over the cable and thus cause temporary attenuation of the light emission from the optical fibre or fibres. The system can also be used for detecting any other cause of the application of pressure to the cable, for example pedestrians walking over it, or blast pressure from an explosion.Since the length of time for which the pressure is applied, and the number of, and time intervals between, pressure applications, can readily be determined from the number, duration and repetition rate of the attenuation signals, it is possible to determine whether a vehicle is of the wheeled or tracked type, that is to say whether it is for example a lorry or a military tank, and if wheeled, the number of pairs of wheels, so that the nature of and size of the vehicle can be estimated. The system can similarly be used for counting vehicles using a given stretch of road, or pedestrians using a pedestrian crossing. Other possible uses include analysis of the "signature" of a vehicle, that is to say the nature of oscillations or other movements of the vehicle, for detecting whether the vehicle is loaded or armed, and how the load or armament is distributed.
Usually the light source is arranged to launch light into one end of the optical fibre cable, while the sensing means is arranged to receive light emitted from the other end of the cable. If desired, however, the light source and sensing means may both be connected to the same end of the cable, means being provided at the other end of the cable for reflecting the emitted light back along the fibre or fibres to the sensing means. Means may also be provided for reflecting the attenuation signals from the point or points at which the pressure is applied to the sensing means, so that, by measuring the time interval between launching of a light pulse into the cable and reception of the reflected signal, the distance along the cable at which deformation occurs can be determined, and hence the point at which, for example, a vehicle is passing can be ascertained.
Suitable reflecting means include a reflectometer or a back-scatter arrangement.
When the light source and sensing means are connected to opposite ends of the cable, the cable is conveniently laid on the ground, usually a flat road surface, in a loop, so that the light source and sensing means can be located adjacent to one another, or a single transmitter-receiver instrument can be employed An additional advantage of the arrangement is that, with the arms of the loop placed a known distance apart, measurement of the time elapsing between corresponding deformations of the cable at points on the two arms by, for example, the passage of the front wheels of a vehicle successively over the two points enables the speed of the vehicle to be determined.
A suitable form of transmitter-receiver instrument which can be used with either the looped cable arrangement, or the light reflection arrangement, described above, is an insertion loss meter which includes a light source, means for monitoring attenuation of the received light, and feedback means for compensating for changes in the output of the light source.

Claims (28)

Claims
1. An optical fibre cable for use for pressure sensing, which is formed of one or more optical fibre modules, wherein each said module consists of or includes a single vitreous optical fibre coated with a resilient buffer layer of polymeric material having an elastic modulus not greater than 10 megapascals, one or more strands of deformable filamentary material having an elastic modulus higher than that of the buffer layer, laid on the surface of the buffered fibre, and a protective sleeve of abrasion-resistant material having an elastic modulus of less than 5 gigapascals, extruded over the filamentary material.
2. A cable according to Claim 1, wherein the said buffer layer in each said module consists of a silicone resin.
3. A cable according to Claim 1 or 2, wherein each said module includes an additional buffering layer composed of amorphous nylon or a meltprocessable polyester, applied over the said buffer layer, the said filamentary material being laid on the surface of said additional buffering layer.
4. A cable according to Claim 1, 2 or 3, wherein the said strand or strands of filamentary material in each said module is or are laid straight along the surface of the buffered fibre, so as to lie substantially parallel to the optical fibre.
5. A cable according to Claim 1, 2 or 3, wherein the said strand or strands of filamentary material in each said module is or are helically wound around the buffered fibre.
6. A cable according to any preceding Claim, wherein the said filamentary strand or strands in each said module is or are formed of resilient material.
7. A cable according to Claim 6, wherein the said strand or strands consist of aromatic polyamide yarns, or glass filaments, or nylon filaments or cord.
8. A cable according to Claim 7, wherein the said strand or strands consist of yarns or individual filaments which are helically wound around the buffered optical fibre in one or more layers so as to cover the buffer coating completely.
9. A cable according to Claim 8, wherein the filamentary winding is impregnated with resin.
10. A cable according to Claim 7, wherein the said strand or strands consist of a cord or cords helically wound around the buffered optical fibre with a pitch not exceeding 50 millimetres.
11. A cable according to any of the preceding Claims 1 to 5, wherein the said filamentary strand or strands in each said module is or are formed of non-resilient material such as ductile metal wire.
12. A cable according to any preceding Claim, wherein the said protective sleeve in each said module is formed of resilient material.
13. A cable according to Claim 12, wherein the said sleeve is formed of melt-processable polyester, or polyethylene, or polyvinyl chloride, or natural or synthetic rubber.
14. A cable according to Claim 12, wherein the said sleeve is formed of polyurethane resin.
1 5. A cable according to any preceding Claim, wherein each said module includes an outer jacket of synthetic resin extruded over the said sleeve.
1 6. A cable according to Claim 1, wherein each said module is of a form hereinbefore described with reference to Figure 1 or Figure 2 or Figure 3 of the accompanying drawings.
1 7. A cable according to any preceding Claim, which consists of two or more of said optical fibre modules, laid straight and parallel to one another or helically intertwisted, enclosed in an outer jacket of synthetic resin.
18. A cable according to Claim 1 5 or 17, wherein said outer jacket of each module, or said outer jacket of the cable, is formed of polyethylene.
1 9. A pressure sensing system which includes an optical fibre cable according to any preceding Claim, laid in a location in which at least part of the length of the cable will be subjected to applied pressure, a light source arranged to launch light into an end of the optical fibre, or of each optical fibre, incorporated in the cable, and sensing means arranged to receive light emitted from an end or ends of the optical fibre or fibres and to detect and indicate a reduction in the intensity of said emitted light resulting from the application of pressure to the cable or to one or more portions of the length thereof.
20. A system according to Claim 19, wherein the said sensing means includes means for converting variations in the intensity of said emitted light into a suitable form of signal for recording or display.
21. A system according to Claim 20, wherein the said sensing means includes means for amplifying the said signals.
22. A system according to Claim 19, 20 or 21, wherein the said sensing means is calibrated to indicate the relationship between the degree of attenuation of the light and the magnitude of the load producing it.
23. A system according to any of the preceding Claims 1 9 to 22, wherein the said sensing means includes means for indicating the duration and repetition rate of the light attenuation signals.
24. A system according to any of the preceding Claims 1 9 to 23, wherein the light source is arranged to launch light into one end of the optical fibre cable, and the sensing means is arranged to receive light emitted from the other end of the cable.
25. A system according to any of the preceding Claims 1 9 to 23, wherein the light source and sensing means are both connected to the same end of the cable, and means are provided at the other end of the cable for reflecting the emitted light back along the optical fibre or fibres to the sensing means.
26. A system according to any of the preceding Claims 1 9 to 25, wherein means are provided for reflecting the light attenuation signals, from the point or points at which the pressure is applied, to the sensing means.
27. A system according to any of the preceding Claims 1 9 to 26, which includes a single transmitter-receiver instrument connected either to both ends of the cable, or to one end when reflecting means at the other end are provided.
28. A system according to Claim 27, wherein the said instrument is an insertion loss meter which includes a light source, means for monitoring attenuation of the received light, and feedback means for compensating for changes in the output of the light source.
GB8027454A 1979-08-30 1980-08-22 Pressure sensitive optical fibre cable Expired GB2058394B (en)

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GB7930093 1979-08-30
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GB2058394B GB2058394B (en) 1984-01-04

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Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0066493A1 (en) * 1981-05-15 1982-12-08 Schlumberger Limited Pressure wave fiber optic transducer cable
EP0082820A2 (en) * 1981-12-21 1983-06-29 Battelle Memorial Institute Optical fibre pressure detector
GB2130611A (en) * 1982-11-22 1984-06-06 Dr A T Ratcliffe Synthetic fibre rope: monitoring strain using optical fires
EP0118592A1 (en) * 1983-02-16 1984-09-19 Felten & Guilleaume Energietechnik AG Tensile strength cable incorporating an optical fibre sensor
US4482890A (en) * 1981-01-22 1984-11-13 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Weight responsive intrusion detector using dual optical fibers
WO1986000988A1 (en) * 1984-07-20 1986-02-13 Telefonaktiebolaget L M Ericsson A fibre-optic cable responsive to microbending forces
DE3526966A1 (en) * 1984-11-14 1986-05-15 Felten & Guilleaume Energietechnik GmbH, 5000 Köln LIGHTWAVE GUIDE SENSOR FOR TOWING FORCES AND METHOD FOR THE PRODUCTION THEREOF
FR2578974A1 (en) * 1985-03-18 1986-09-19 Lach Pierre Optical device for analogue detection of a force
US4654520A (en) * 1981-08-24 1987-03-31 Griffiths Richard W Structural monitoring system using fiber optics
US4668861A (en) * 1984-12-12 1987-05-26 The Regents Of The University Of California Tactile sensor employing a light conducting element and a resiliently deformable sheet
GB2183026A (en) * 1985-11-14 1987-05-28 Battelle Development Corp Fiber-optical pressure detector
GB2188719A (en) * 1986-04-02 1987-10-07 Stc Plc Optical fibres
US4840481A (en) * 1987-12-10 1989-06-20 Simmonds Precision Polarimetric optical frequency domain distributed strain sensor and method
EP0328703A1 (en) * 1988-02-17 1989-08-23 Wolfgang Brunner Measuring method for local measurement of pressures
US4927232A (en) * 1985-03-18 1990-05-22 G2 Systems Corporation Structural monitoring system using fiber optics
AU597937B2 (en) * 1985-03-18 1990-06-14 G2 Systems Corporation Structural monitoring system using fiber optics
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
US5026141A (en) * 1981-08-24 1991-06-25 G2 Systems Corporation Structural monitoring system using fiber optics
EP0634004A1 (en) * 1992-04-02 1995-01-18 Lockheed Martin Energy Systems, Inc. Apparatus for weighing and identifying characteristics of a moving vehicle
EP1128171A1 (en) * 2000-02-22 2001-08-29 Sensor Line Gesellschaft für optoelektronische Sensoren mbH Fibre optic load sensor for detecting railway vehicles
EP1143272A2 (en) * 2000-04-05 2001-10-10 Lucent Technologies Inc. Mechanically induced, reversible, long period optical fiber gratings
JP2009145250A (en) * 2007-12-17 2009-07-02 Hitachi Cable Ltd Optical fiber load sensor
JP2009229311A (en) * 2008-03-24 2009-10-08 Fukui Prefecture Optical fiber cable for pressure detection
WO2012084997A3 (en) * 2010-12-21 2013-04-04 Shell Internationale Research Maatschappij B.V. Detecting the direction of acoustic signals with a fiber optical distributed acoustic sensing (das) assembly
CN111094654A (en) * 2017-08-16 2020-05-01 维尔西斯***与技术维里亚公司 System for monitoring the dynamic weight and speed of a vehicle on a road
US10837805B2 (en) 2014-10-08 2020-11-17 Optasense Holdings Limited Fibre optic cable with tuned transverse sensitivity

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Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4482890A (en) * 1981-01-22 1984-11-13 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Weight responsive intrusion detector using dual optical fibers
EP0066493A1 (en) * 1981-05-15 1982-12-08 Schlumberger Limited Pressure wave fiber optic transducer cable
US4654520A (en) * 1981-08-24 1987-03-31 Griffiths Richard W Structural monitoring system using fiber optics
US5026141A (en) * 1981-08-24 1991-06-25 G2 Systems Corporation Structural monitoring system using fiber optics
EP0082820A3 (en) * 1981-12-21 1984-03-21 Battelle Memorial Institute Optical fibre pressure detector
EP0082820A2 (en) * 1981-12-21 1983-06-29 Battelle Memorial Institute Optical fibre pressure detector
GB2130611A (en) * 1982-11-22 1984-06-06 Dr A T Ratcliffe Synthetic fibre rope: monitoring strain using optical fires
EP0118592A1 (en) * 1983-02-16 1984-09-19 Felten & Guilleaume Energietechnik AG Tensile strength cable incorporating an optical fibre sensor
AU575196B2 (en) * 1984-07-20 1988-07-21 Telefonaktiebolaget Lm Ericsson (Publ) A fibre-optic cable responsive to microbending forces
WO1986000988A1 (en) * 1984-07-20 1986-02-13 Telefonaktiebolaget L M Ericsson A fibre-optic cable responsive to microbending forces
DE3526966A1 (en) * 1984-11-14 1986-05-15 Felten & Guilleaume Energietechnik GmbH, 5000 Köln LIGHTWAVE GUIDE SENSOR FOR TOWING FORCES AND METHOD FOR THE PRODUCTION THEREOF
EP0182030A1 (en) * 1984-11-14 1986-05-28 Felten & Guilleaume Energietechnik AG Traction force-sensitive optical fibre cable and its manufacturing process
US4668861A (en) * 1984-12-12 1987-05-26 The Regents Of The University Of California Tactile sensor employing a light conducting element and a resiliently deformable sheet
FR2578974A1 (en) * 1985-03-18 1986-09-19 Lach Pierre Optical device for analogue detection of a force
US4927232A (en) * 1985-03-18 1990-05-22 G2 Systems Corporation Structural monitoring system using fiber optics
AU597937B2 (en) * 1985-03-18 1990-06-14 G2 Systems Corporation Structural monitoring system using fiber optics
GB2183026A (en) * 1985-11-14 1987-05-28 Battelle Development Corp Fiber-optical pressure detector
GB2183026B (en) * 1985-11-14 1989-11-22 Battelle Development Corp Fiber-optical pressure detector
GB2188719A (en) * 1986-04-02 1987-10-07 Stc Plc Optical fibres
GB2188719B (en) * 1986-04-02 1990-08-22 Stc Plc Optical fibres
US4840481A (en) * 1987-12-10 1989-06-20 Simmonds Precision Polarimetric optical frequency domain distributed strain sensor and method
EP0328703A1 (en) * 1988-02-17 1989-08-23 Wolfgang Brunner Measuring method for local measurement of pressures
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