WO2024069619A1 - Method for the measuring of integrated deformations along a direction of a structure by means of an optical fiber sensor, and a system for the implementation of said method - Google Patents

Method for the measuring of integrated deformations along a direction of a structure by means of an optical fiber sensor, and a system for the implementation of said method Download PDF

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Publication number
WO2024069619A1
WO2024069619A1 PCT/IB2023/062122 IB2023062122W WO2024069619A1 WO 2024069619 A1 WO2024069619 A1 WO 2024069619A1 IB 2023062122 W IB2023062122 W IB 2023062122W WO 2024069619 A1 WO2024069619 A1 WO 2024069619A1
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WO
WIPO (PCT)
Prior art keywords
measuring
optical fiber
sensor
integrated
deformations
Prior art date
Application number
PCT/IB2023/062122
Other languages
French (fr)
Inventor
Maurizio MIRABILE
Original Assignee
Optosensing S.R.L.
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 Optosensing S.R.L. filed Critical Optosensing S.R.L.
Publication of WO2024069619A1 publication Critical patent/WO2024069619A1/en

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Classifications

    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35341—Sensor working in transmission
    • G01D5/35345—Sensor working in transmission using Amplitude variations to detect the measured quantity
    • 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
    • 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
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/08—Testing mechanical properties
    • G01M11/083—Testing mechanical properties by using an optical fiber in contact with the device under test [DUT]
    • G01M11/085—Testing mechanical properties by using an optical fiber in contact with the device under test [DUT] the optical fiber being on or near the surface of the DUT
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
    • G01M5/0041—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
    • G01M5/0091—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by using electromagnetic excitation or detection

Definitions

  • the present invention relates to a method for the measuring of integrated deformations of a structure using a optical fiber sensor and, more precisely, to a method for the measuring of integrated deformations of a structure , which provides the use of a system comprising an elastic optical fiber sensor arranged on the surface of the structure according to a determined geometric pattern, the sensor being able to detect the deformation of the structure along a direction thereof and following the deformation of the sensor .
  • the use of the so-called “punctual sensors” in the "Bragg grating” technology is foreseen .
  • other types of measuring systems provide the use of “distributed sensors” , which are able to measure deformation profiles along the entire length of the fiber (via Brillouin scattering) .
  • Both of these types of systems involve technologies that show signi ficant costs , and which limit the use thereof to cases wherein the monitoring of deformations must be performed in particularly noi sy environments from an electromagnetic point of view (Bragg grating sensors ) , or where it is necessary to monitor deformation profiles on very long stretches (such as , for example , dams , bridges , tunnels , etc . ) , and where the value of the deformation at all points coinciding with the spatial resolution of the system is needed to be known .
  • Aim of the present invention is to solve the above mentioned disadvantages of the aforementioned state-of-the- art technologies , by providing a method for the measuring of integrated deformations of a structure wherein the use of a system which includes an elastic optical fiber sensor arranged onto the surface of the structure and according to a determined geometric pattern is provided, and which is capable of detecting the deformation along a direction of the structure and following deformation of the sensor .
  • the present invention provides a method for the measuring of integrated deformations which involves the use of a system which includes a polymer optical fiber sensor, the sensor being capable of being mounted on the surface of a structure to be measured and according to a speci fic geometric arrangement , and in such a way as to detect the deformation along a direction following the deformation of the sensor .
  • the present invention provides a method and a system for the measuring of deformations of a structure substantially according to the appended claims .
  • the system foresees the use of a polymeric optical fiber which, when applied onto the surface of the structure to be measured and according to a speci fic geometric arrangement , it allows the measuring of the integral deformation applied along a speci fic measuring axis of the structure .
  • the geometry of the sensor is substantially a sinusoidal geometry .
  • the variation of the tensile stress appl ied onto the fiber of the sinusoidal-shaped sensor generates an increase in the signal detected by a photodiode associated with the fiber .
  • the variation of the compressive stress applied on the fiber of the sinusoidal-shaped sensor generates an attenuation of the signal detected by a photodiode associated with the fiber .
  • Figure 1 is a schematical view illustrating the geometric arrangement of the sensor of the measuring system of the present invention
  • Figure 2 is a schematical view illustrating a first operating condition of the sensor of the measuring system of the present invention.
  • Figure 3 is a schematical view illustrating a second operating condition of the sensor of the measuring system of the present invention .
  • a measuring system for a structure comprising a device for the measuring of the deformations of the structure, which substantially comprises the following components :
  • a first stage which includes a series of digital potentiometers , the potentiometers being set by a microprocessor to an optimal gain value , the arrangement is such that the output current of a photodiode associated with a polymer optical fiber is converted into a value o f optimal voltage at an input of an Analog/Digital converter, and with the aim of guaranteeing maximum measuring dynamics depending on the system configuration;
  • a second stage which comprises an Analog/Digital converter which measures , at high resolution, the signals coming from the photodiode , appropriately converted into voltage ;
  • a third stage which includes a microprocessor that manages the entire measuring .
  • the aforementioned microprocessor has the following functions : a ) automatically setting of the entire system, to guarantee the maximum possible dynamics ; b ) communicating with the Analog/Digital converter ; and c ) communicating with a "Host Unit" for data acquisition and processing .
  • the optical fiber sensor is a sensor made of a polymeric optical fibre , which is arranged onto the surface of a structure (the latter not being illustrated in the figure ) and according to a speci fic geometric arrangement , the arrangement essentially consisting of a sinusoidal pattern .
  • the optical fiber sensor is mounted onto the surface of the structure to be measured along a determined direction .
  • the geometry of the sensor substantially a sinusoidal shaped geometry, following to a variation of a tensile stress applied to the sensor fiber, it causes an increase in the signal detected by the photodiode associated with the optical fiber sensor .
  • the variation of the signal to the photodiode is processed by the microprocessor which trans forms the former into a value/parameter related to a determined deformation value relevant to the structure associated to the fiber sensor .

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Optical Transform (AREA)

Abstract

A system for the measuring of integrated deformations along a direction of a structure by means of an optical fiber sensor is provided, the system comprising a device for the measuring of the deformations of said structure, wherein the measuring device comprises the following components : a first stage, comprising a series of digital potentiometers, said potentiometers being set to an optimal gain value via a microprocessor; a second stage, comprising an Analog/Digital converter capable of carrying out a high resolution measuring of signals coming from said photodiode once said signals are converted into voltage; and a third stage, comprising said Microprocessor capable of managing the entire measuring, the system is characterized by the fact that said microprocessor performs the following operations : a ) automatically setting the entire system for obtaining the maximum possible dynamics; b ) communicating with said Analog/Digital converter; and c ) communicating with a "Host Unit" for data acquisition and processing.

Description

"METHOD FOR THE MEASURING OF INTEGRATED DEFORMATIONS ALONG
A DIRECTION OF A STRUCTURE BY MEANS OF AN OPTICAL FIBER
SENSOR, AND A SYSTEM FOR THE IMPLEMENTATION OF SAID METHOD" >»X<« DESCRIPTION
The present invention relates to a method for the measuring of integrated deformations of a structure using a optical fiber sensor and, more precisely, to a method for the measuring of integrated deformations of a structure , which provides the use of a system comprising an elastic optical fiber sensor arranged on the surface of the structure according to a determined geometric pattern, the sensor being able to detect the deformation of the structure along a direction thereof and following the deformation of the sensor .
State of the art
As is known, today there are di f ferent types of methods and related systems for the measuring of deformations by using optical fibres . These deformation measuring systems find application in the monitoring and the measuring of deformations in civil building such as dams , bridges , tunnels , etc . but also di f ferent applications such as the measuring of deformations for particular structures .
According to a first type of such systems , the use of the so-called "punctual sensors" in the "Bragg grating" technology is foreseen . Alternatively, other types of measuring systems provide the use of "distributed sensors" , which are able to measure deformation profiles along the entire length of the fiber (via Brillouin scattering) . Both of these types of systems involve technologies that show signi ficant costs , and which limit the use thereof to cases wherein the monitoring of deformations must be performed in particularly noi sy environments from an electromagnetic point of view (Bragg grating sensors ) , or where it is necessary to monitor deformation profiles on very long stretches ( such as , for example , dams , bridges , tunnels , etc . ) , and where the value of the deformation at all points coinciding with the spatial resolution of the system is needed to be known .
The aforementioned technologies have the enormous disadvantage given that they find it very di f ficult to be applied in all those circumstances in which the cost of the measuring system has a considerable impact with respect to the application thereof . For example , in the monitoring of rockfall protection networks , in the monitoring of geocomposites for the consolidation of landslide slopes , and wherever it is suf ficient to measure the integral deformation of the support on which the fiber is applied .
Aim of the present invention is to solve the above mentioned disadvantages of the aforementioned state-of-the- art technologies , by providing a method for the measuring of integrated deformations of a structure wherein the use of a system which includes an elastic optical fiber sensor arranged onto the surface of the structure and according to a determined geometric pattern is provided, and which is capable of detecting the deformation along a direction of the structure and following deformation of the sensor .
BRIEF DESCRIPTION OF THE INVENTION Therefore , the present invention provides a method for the measuring of integrated deformations which involves the use of a system which includes a polymer optical fiber sensor, the sensor being capable of being mounted on the surface of a structure to be measured and according to a speci fic geometric arrangement , and in such a way as to detect the deformation along a direction following the deformation of the sensor .
Therefore , the present invention provides a method and a system for the measuring of deformations of a structure substantially according to the appended claims .
According to a first inventive aspect of the present invention, the system foresees the use of a polymeric optical fiber which, when applied onto the surface of the structure to be measured and according to a speci fic geometric arrangement , it allows the measuring of the integral deformation applied along a speci fic measuring axis of the structure .
According to a second inventive aspect , the geometry of the sensor is substantially a sinusoidal geometry .
According to a third inventive aspect of the present invention, the variation of the tensile stress appl ied onto the fiber of the sinusoidal-shaped sensor generates an increase in the signal detected by a photodiode associated with the fiber .
According to a fourth inventive aspect , the variation of the compressive stress applied on the fiber of the sinusoidal-shaped sensor generates an attenuation of the signal detected by a photodiode associated with the fiber . DETAILED DESCRIPTION OF THE INVENTION
A detailed description of a preferred embodiment of the method and the system for the measuring of integrated deformations of a structure using the optical fiber sensor of the present invention will now be provided, given by way of a not limiting example , and with reference to the attached drawings , wherein :
Figure 1 is a schematical view illustrating the geometric arrangement of the sensor of the measuring system of the present invention;
Figure 2 is a schematical view illustrating a first operating condition of the sensor of the measuring system of the present invention; and
Figure 3 is a schematical view illustrating a second operating condition of the sensor of the measuring system of the present invention .
With reference now to figure 1 , according to the present invention a measuring system for a structure is provided, the system comprising a device for the measuring of the deformations of the structure, which substantially comprises the following components :
- A first stage which includes a series of digital potentiometers , the potentiometers being set by a microprocessor to an optimal gain value , the arrangement is such that the output current of a photodiode associated with a polymer optical fiber is converted into a value o f optimal voltage at an input of an Analog/Digital converter, and with the aim of guaranteeing maximum measuring dynamics depending on the system configuration; - A second stage which comprises an Analog/Digital converter which measures , at high resolution, the signals coming from the photodiode , appropriately converted into voltage ; and
- A third stage which includes a microprocessor that manages the entire measuring .
The aforementioned microprocessor has the following functions : a ) automatically setting of the entire system, to guarantee the maximum possible dynamics ; b ) communicating with the Analog/Digital converter ; and c ) communicating with a "Host Unit" for data acquisition and processing .
As can be seen in the figure and according to the present invention, the optical fiber sensor is a sensor made of a polymeric optical fibre , which is arranged onto the surface of a structure ( the latter not being illustrated in the figure ) and according to a speci fic geometric arrangement , the arrangement essentially consisting of a sinusoidal pattern . The optical fiber sensor is mounted onto the surface of the structure to be measured along a determined direction .
It is necessary to highlight here that the use of a polymer optical fiber allows the measuring of the integral deformation applied along a given measuring axis .
Furthermore , being the geometry of the sensor substantially a sinusoidal shaped geometry, following to a variation of a tensile stress applied to the sensor fiber, it causes an increase in the signal detected by the photodiode associated with the optical fiber sensor .
On the other hand, following to a variation of a compressive stress applied to the optical fiber sensor, it generates an attenuation of the signal detected by the photodiode associated with the optical fiber sensor .
As can be understood in figure 2 , by applying a tensile stress on the fiber it causes a decrease in attenuation along the fiber, and consequently an increase of the signal detected by the photodiode .
As illustrated in figure 3 , by applying a compressive stress on the fiber it causes an attenuation of the signal detected by the photodiode .
The variation of the signal to the photodiode is processed by the microprocessor which trans forms the former into a value/parameter related to a determined deformation value relevant to the structure associated to the fiber sensor .

Claims

1 . A system for the measuring of integrated deformations along one direction of a structure via an optical fiber sensor, comprising a device for the measuring of the deformations of said structure , wherein said measuring device comprises the following components :
A first stage , comprising a series of digital potentiometers , said digital potentiometers being settable to an optimal gain value via a Microprocessor, the arrangement being such that an output current of a photodiode associated with a polymer optical fiber is converted into an optimal voltage value at an input of an Analog/Digital converter ;
A second stage , comprising said Analog/Digital converter capable of carrying out a high-resolution measuring of signals coming from said photodiode once said signals are converted into voltage ; and
- A third stage , comprising said Microprocessor capable of managing the entire measuring; characterized in that said microprocessor performs the following operations : a ) automatically setting the entire system to obtain the maximum possible dynamics ; b ) communicating with said Analog/Digital converter ; and c ) communicating with a "Host Unit" for data acquisition and processing .
2 . A system for the measuring of integrated deformations along one direction of a structure via an optical fiber sensor according to the preceding claim, wherein said optical fiber sensor is a sensor made of polymeric optical fiber .
3. A system for the measuring of integrated deformations along one direction of a structure via an optical fiber sensor according to the preceding claim, wherein said optical fiber sensor is arranged onto the surface of said structure according to a determined geometric pattern consisting of a sinusoidal pattern and along a direction of said structure .
4 . A system for the measuring of integrated deformations along one direction of a structure via an optical fiber sensor according to any of the preceding claims , wherein the geometry of said sensor is such that a variation of a tensile stress applied to the fiber of said sensor causes an increase in the signal detected by said photodiode associated with said fiber .
5 . A system for the measuring of integrated deformations along one direction of a structure via an optical fiber sensor according to any of the preceding claims , wherein the geometry of said sensor is such that a variation in a compressive stress applied to said optical fiber of said sensor causes an attenuation in the signal detected by said photodiode associated with said fiber .
PCT/IB2023/062122 2022-10-01 2023-12-01 Method for the measuring of integrated deformations along a direction of a structure by means of an optical fiber sensor, and a system for the implementation of said method WO2024069619A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT202200016344 2022-10-01
IT102022000016344 2022-10-01

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4734577A (en) * 1986-01-30 1988-03-29 Grumman Aerospace Corporation Continuous strain measurement along a span
US5701370A (en) * 1995-08-11 1997-12-23 Lockheed Martin Energy Systems, Inc. Optical fiber sensors for monitoring joint articulation and chest expansion of a human body
JP2011169592A (en) * 2008-05-30 2011-09-01 Soka Univ Measuring instrument and measuring system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4734577A (en) * 1986-01-30 1988-03-29 Grumman Aerospace Corporation Continuous strain measurement along a span
US5701370A (en) * 1995-08-11 1997-12-23 Lockheed Martin Energy Systems, Inc. Optical fiber sensors for monitoring joint articulation and chest expansion of a human body
JP2011169592A (en) * 2008-05-30 2011-09-01 Soka Univ Measuring instrument and measuring system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SILVA-LOPEZ M ET AL: "STRAIN AND TEMPERATURE SENSITIVITY OF A SINGLE-MODE POLYMER OPTICAL FIBER", OPTICS LETTERS, OPTICAL SOCIETY OF AMERICA, US, vol. 30, no. 23, 1 December 2005 (2005-12-01), pages 3129 - 3131, XP001237603, ISSN: 0146-9592, DOI: 10.1364/OL.30.003129 *

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