CN104697682A - Fiber Bragg grating strain-measuring method and fiber Bragg grating strain sensor - Google Patents
Fiber Bragg grating strain-measuring method and fiber Bragg grating strain sensor Download PDFInfo
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- CN104697682A CN104697682A CN201410133870.6A CN201410133870A CN104697682A CN 104697682 A CN104697682 A CN 104697682A CN 201410133870 A CN201410133870 A CN 201410133870A CN 104697682 A CN104697682 A CN 104697682A
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- fiber grating
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Abstract
The invention discloses a fiber Bragg grating strain-measuring method and a fiber Bragg grating strain sensor. The sensor comprises three fiber Bragg grating sensing modules, a thin-wall ring, a temperature compensating block, signal transmission fibers and a fiber Bragg grating demodulator. The fiber Bragg grating sensing modules are serially connected through the signal transmission fibers and are attached to left and right ends of the thin-wall ring and the surface of the temperature compensating block connected with the thin-wall ring; the fiber Bragg grating demodulator is connected with one of the fiber Bragg grating sensing modules connected to the left and right ends of the thin-wall ring through the signal transmission fiber. The fiber Bragg grating strain-measuring method and the fiber Bragg grating strain sensor have the advantages that measurement readings are more accurate and reliable, electromagnetic interference is resisted, corrosion is resisted, and measuring is automated.
Description
Technical field
The invention belongs to fiber optic sensor technology field, particularly relate to a kind of fiber grating sensor of measuring force.
Background technology
Force cell in tradition earthwork test Instrument, the general dial gauge that uses carries out reading, and anti-interference is poor, reading out of true, and coefficient needs often to demarcate, and cannot real-time data collection.Optical fiber sensing technology is the sensing technology starting late 1970s to rise.Fibre Optical Sensor has that volume is little, quality is light, electromagnetism interference, anticorrosion, highly sensitive, the easy advantage such as integrated.Fiber-optic grating sensor (FBG) be wherein the fibre core of light-sensitive optical fibre under the irradiation of intense UV light, the narrow band filter that the refractive index generating period of fibre core forever changes.The parameter such as temperature and strain can cause the change of FBG reflected light centre wavelength, and its computing formula is as follows:
λ
bwith Δ λ
bthe initial center wavelength of reflected light and the drift value of centre wavelength respectively.Δ ε and Δ T is strain suffered by optical fiber, temperature variation respectively.C ε and C
tthe coefficient of strain and the temperature coefficient of fiber grating respectively.Its value is about 0.78 × 10
?6μ ε
?1with 6.67 × 10
?6dEG C
?1.Fiber grating pair strain, temperature are all very responsive, and the cross effect both when monitoring can not be ignored, otherwise the data of soil test gained can be caused inaccurate, therefore needs to adopt effective temperature compensation measure.
Summary of the invention
For the deficiencies in the prior art, the object of this invention is to provide a kind of fiber grating force measuring method and sensor, to make the data measured by soil test more accurate, reliable, and realize automatic measurement.
For achieving the above object, the present invention adopts following technical scheme:
A kind of fiber grating sensor of measuring force, comprise a plurality of optical fiber grating sensing module, thin wall circular, temperature compensation block, signal transmission fiber and fiber Bragg grating (FBG) demodulator, this a plurality of optical fiber grating sensing module is connected mutually by signal transmission fiber, and the temperature compensation block surface be connected on the both sides outer wall being separately fixed at thin wall circular and with thin wall circular, described temperature compensation block is distributed in any position in described thin wall circular simultaneously, described fiber Bragg grating (FBG) demodulator is connected by signal transmission fiber with any one in the two or more optical fiber grating sensing module be connected on the outer wall of described thin wall circular both sides.
As the further optimization of such scheme, the weld cover of described optical fiber grating sensing module and signal transmission fiber has heat-shrinkable T bush.
As the further optimization of such scheme, described temperature compensation block is made up of identical elastic metallic material with thin wall circular, such guarantee to temperature compensation accurately with consistent.
As the further optimization of such scheme, described optical fiber grating sensing module is pasted and fixed on described thin wall circular outer wall and described temperature compensation block on the surface respectively, because optical fiber grating sensing module is soft, the mode guarantee optical fiber grating sensing module of stickup is only had evenly to be close to thin wall circular outer wall and described temperature compensation block, adopt the mode of binding and welding all can not realize optical fiber grating sensing module and thin wall circular outer wall and described temperature compensation block closely to stick together uniformly, can error be caused.
As another aspect of the present invention, additionally provide a kind of fiber grating force measuring method, comprise: a thin wall circular is provided, and at least one optical fiber grating sensing module is fixedly connected with respectively on the both sides outer wall of described thin wall circular, and any position connects at least one temperature compensation block in described thin wall circular, and be fixedly connected with at least one optical fiber grating sensing module on described temperature compensation block surface
With signal transmission fiber, all optical fiber grating sensing modules are connected mutually, and fiber Bragg grating (FBG) demodulator are connected by signal transmission fiber with any one in the two or more optical fiber grating sensing module be fixed on the outer wall of described thin wall circular both sides,
And, pulling force or pressure is applied to described thin wall circular ring wall, the optical fiber grating sensing module be fixed on thin wall circular outer wall is strained, with the mean value of fiber Bragg grating (FBG) demodulator record reading strain, and automatically carry out temperature compensation according to the dependent variable of the optical fiber grating sensing module being fixed on temperature compensation block surface, thus obtain the size of described thin wall circular strain value.
Further, apply pulling force or pressure by thin wall circular ring wall described in static loading normal direction, and then realize the demarcation to described fiber grating sensor of measuring force.
Further, described temperature compensation block is made up of identical elastic metallic material with thin wall circular.
Beneficial effect main manifestations of the present invention is: dynamometry reading is more accurate, reliable, electromagnetism interference, anticorrosion, and achieves automatic measurement.
Accompanying drawing explanation
Fig. 1 is the structural representation of one embodiment of the invention fiber grating sensor of measuring force.
Fig. 2 is the rating test schematic diagram of fiber grating sensor of measuring force in one embodiment of the invention.
Wherein, 1 is the first optical fiber grating sensing module, and 2 is thin wall circular, and 3 is temperature compensation block, and 4 is signal transmission fibers, and 5 is fiber Bragg grating (FBG) demodulators, and 6 is second optical fiber grating sensing modules, and 7 is the 3rd optical fiber grating sensing modules, and 8 is hooks, and 9 is counterweights.
Embodiment
Below in conjunction with accompanying drawing and an embodiment, more specific detail is done to technical scheme of the present invention.
Embodiment 1
A kind of fiber grating sensor of measuring force, comprise three optical fiber grating sensing modules 1,6 and 7, thin wall circular 2, temperature compensation block 3, signal transmission fiber 4 and fiber Bragg grating (FBG) demodulator 5, described three optical fiber grating sensing modules are by being pasted onto the left and right two ends of thin wall circular 2 outer wall respectively after signal transmission fiber 4 mutually series connection, and temperature compensation block 3 surface to be connected with thin wall circular 2, described fiber Bragg grating (FBG) demodulator 5 is connected by signal transmission fiber with the 3rd optical fiber grating sensing module 7 being connected to the left and right two ends of thin wall circular 2 outer wall.Described thin wall circular 2 and temperature compensation block 3 all adopt metal material to be formed.In described three optical fiber grating sensing modules, the first optical fiber grating sensing module 1 and the 3rd optical fiber grating sensing module 7 are in order to survey the strain of annulus outer wall, and the second optical fiber grating sensing module 6 is in order to carry out temperature compensation to reading strain.The mutual weld cover of described three optical fiber grating sensing modules and signal transmission fiber 4 has heat-shrinkable T bush, and described sleeve pipe is the transparent plastic heat-shrinkable T bush of long 3cm.Described three optical fiber grating sensing modules adopt glue to be pasted onto respectively on the outer wall of thin wall circular 2 and the surface of temperature compensation block 3.The centre wavelength reading of described three optical fiber grating sensing modules is gathered automatically by fiber Bragg grating (FBG) demodulator 5.Described fiber grating sensor of measuring force adopts static loading method to carry out the demarcation of sensor.
According to the thin wall circular Stress calculation formula of Timoshenko in Elasticity, the formula of the inside and outside wall hoop strain of thin wall circular can be obtained:
The wherein thickness of ω-annulus
The width of δ-annulus
The radial forces that both direction on F-annulus suffered by unit thickness is contrary
The elastic modulus of E-annulus
θ-position angle
R
athe central diameter of-annulus
When θ=90 °, the absolute value of annulus strain | ε | reach maximal value,
wherein K is calibration coefficient.When θ=50.46 °, ε value is 0.
Learn that the left and right two ends at the inside and outside wall of annulus strain maximum by above calculating.When applied pressure, circle ring inner wall is subject to compressive strain, and outer wall is subject to stretching strain.Therefore two in optical fiber grating sensing module are circumferentially pasted onto respectively the left and right two ends of thin wall circular 2 outer wall.The second optical fiber grating sensing module 6 in optical fiber grating sensing module is pasted onto on the surface of temperature compensation block 3.
Thin wall circular 2 is main stressed member, when thin wall circular 2 drawn, the effect of pressure time, be pasted onto the first optical fiber grating sensing module 1 in thin wall circular 2 and the 3rd optical fiber grating sensing module 7 thereupon together with strain, this strain is drifted about making the centre wavelength of optical fiber grating sensing module reflected light, fiber Bragg grating (FBG) demodulator 5 can record wavelength shift in real time, thus obtains the size of annulus outer wall strain value.In order to eliminate measuring error, the strain value that the first optical fiber grating sensing module 1 and the 3rd optical fiber grating sensing module 7 record being averaging processing, obtaining mean strain value.Because the second optical fiber grating sensing module 6 reading be pasted onto in temperature compensation block 3 is only subject to the impact of temperature, so can realize the auto thermal compensation of reading strain by it.
Three optical fiber grating sensing modules and signal transmission fiber 4, when making, are first welding together with optical fiber splicer, then optical fiber grating sensing module are pasted assigned address by the present embodiment.Fiber grating dynamometer is left standstill 24h, glue is parched completely; Be connected with fiber Bragg grating (FBG) demodulator 5 by one end FC/APC joint of the signal transmission fiber 4 with optical fiber grating sensing module, fiber Bragg grating (FBG) demodulator 5 is connected with computing machine.The reading of optical fiber grating sensing module, can be real-time transmitted in the monitoring system be made up of (FBG) demodulator and computing machine by optical fiber, carry out reading acquisition and processing.
By the rating test of one group of static loading can obtain the present embodiment mean strain and external force change between relation, as shown in Figure 2, its computing formula is | ε |=KF.The embodiment of test comprises: hang in fiber grating sensor of measuring force by pallet hook 8, etc. the initial reading read after stable reading now, then increase counterweight 9 one by one, record data successively, draw finally by calculating, the value of calibration coefficient K can be obtained.Test findings can be verified by theoretical formula, also mutually can check with dial gauge reading.
In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of application claims.
Claims (7)
1. a fiber grating sensor of measuring force, it is characterized in that comprising a plurality of optical fiber grating sensing module, thin wall circular, temperature compensation block, signal transmission fiber and fiber Bragg grating (FBG) demodulator, this a plurality of optical fiber grating sensing module is connected mutually by signal transmission fiber, and the temperature compensation block surface be connected on the both sides outer wall being separately fixed at thin wall circular and with thin wall circular, described temperature compensation block is distributed in any position in described thin wall circular simultaneously, described fiber Bragg grating (FBG) demodulator is connected by signal transmission fiber with any one in the two or more optical fiber grating sensing module be connected on the outer wall of described thin wall circular both sides.
2. fiber grating sensor of measuring force according to claim 1, is characterized in that, the weld cover of described optical fiber grating sensing module and signal transmission fiber has heat-shrinkable T bush.
3. fiber grating sensor of measuring force according to claim 1, is characterized in that, described temperature compensation block is made up of identical elastic metallic material with thin wall circular.
4. fiber grating sensor of measuring force according to claim 1, is characterized in that, described optical fiber grating sensing module is pasted and fixed on described thin wall circular outer wall and described temperature compensation block on the surface respectively.
5. a fiber grating force measuring method, is characterized in that comprising:
One thin wall circular is provided, and at least one optical fiber grating sensing module is fixedly connected with respectively on the both sides outer wall of described thin wall circular, and any position connects at least one temperature compensation block in described thin wall circular, and be fixedly connected with at least one optical fiber grating sensing module on described temperature compensation block surface
With signal transmission fiber, all optical fiber grating sensing modules are connected mutually, and fiber Bragg grating (FBG) demodulator are connected by signal transmission fiber with any one in the two or more optical fiber grating sensing module be fixed on the outer wall of described thin wall circular both sides,
And, pulling force or pressure is applied to described thin wall circular ring wall, the optical fiber grating sensing module be fixed on thin wall circular outer wall is strained, with the mean value of fiber Bragg grating (FBG) demodulator record reading strain, and automatically carry out temperature compensation according to the dependent variable of the optical fiber grating sensing module being fixed on temperature compensation block surface, thus obtain the size of described thin wall circular strain value.
6. fiber grating force measuring method according to claim 5, is characterized in that comprising: apply pulling force or pressure by thin wall circular ring wall described in static loading normal direction, and then realizes the demarcation to described optical fiber grating sensing module.
7. the fiber grating force measuring method according to claim 5 or 6, is characterized in that comprising: described temperature compensation block is made up of identical elastic metallic material with thin wall circular.
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Cited By (8)
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| CN105066898A (en) * | 2015-08-16 | 2015-11-18 | 北京航空航天大学 | Method for calibrating surface-mounted fiber grating strain sensor |
| CN106525301A (en) * | 2016-12-22 | 2017-03-22 | 南京大学 | Force and displacement measurement method and sensor based on distributed optical fiber sensing |
| CN108759701A (en) * | 2018-05-02 | 2018-11-06 | 中交第二航务工程局有限公司 | Optical fiber vibratory string combines and the adjustable surface-mount type sensor of initial value |
| CN110940445A (en) * | 2019-12-16 | 2020-03-31 | 中国工程物理研究院化工材料研究所 | Optical fiber ring type residual stress test system and residual stress test method |
| CN111473733A (en) * | 2020-04-24 | 2020-07-31 | 珠海任驰光电科技有限公司 | Ultra-large range fiber grating displacement sensor and measuring method |
| CN114459645A (en) * | 2022-01-18 | 2022-05-10 | 武汉理工大学 | Fiber grating pressure sensor based on arc hinge |
| CN114910198A (en) * | 2022-03-28 | 2022-08-16 | 中交第二航务工程局有限公司 | Fiber grating side friction resistance sensor and calibration device and method |
| WO2023029313A1 (en) * | 2021-09-03 | 2023-03-09 | 河北地质大学 | Fiber bragg grating sensor applied to underground stress monitoring |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105066898B (en) * | 2015-08-16 | 2017-08-22 | 北京航空航天大学 | A kind of scaling method of surface-mount type fiber Bragg grating strain sensor |
| CN105066898A (en) * | 2015-08-16 | 2015-11-18 | 北京航空航天大学 | Method for calibrating surface-mounted fiber grating strain sensor |
| CN106525301B (en) * | 2016-12-22 | 2023-01-06 | 南京大学 | Force and displacement measuring method and sensor based on distributed optical fiber sensing |
| CN106525301A (en) * | 2016-12-22 | 2017-03-22 | 南京大学 | Force and displacement measurement method and sensor based on distributed optical fiber sensing |
| CN108759701A (en) * | 2018-05-02 | 2018-11-06 | 中交第二航务工程局有限公司 | Optical fiber vibratory string combines and the adjustable surface-mount type sensor of initial value |
| CN110940445B (en) * | 2019-12-16 | 2021-03-16 | 中国工程物理研究院化工材料研究所 | Optical fiber ring type residual stress test system and residual stress test method |
| CN110940445A (en) * | 2019-12-16 | 2020-03-31 | 中国工程物理研究院化工材料研究所 | Optical fiber ring type residual stress test system and residual stress test method |
| CN111473733A (en) * | 2020-04-24 | 2020-07-31 | 珠海任驰光电科技有限公司 | Ultra-large range fiber grating displacement sensor and measuring method |
| WO2023029313A1 (en) * | 2021-09-03 | 2023-03-09 | 河北地质大学 | Fiber bragg grating sensor applied to underground stress monitoring |
| CN114459645A (en) * | 2022-01-18 | 2022-05-10 | 武汉理工大学 | Fiber grating pressure sensor based on arc hinge |
| CN114459645B (en) * | 2022-01-18 | 2023-05-23 | 武汉理工大学 | Fiber grating pressure sensor based on arc hinge |
| CN114910198A (en) * | 2022-03-28 | 2022-08-16 | 中交第二航务工程局有限公司 | Fiber grating side friction resistance sensor and calibration device and method |
| CN114910198B (en) * | 2022-03-28 | 2023-05-05 | 中交第二航务工程局有限公司 | Fiber bragg grating side friction resistance sensor and calibration device and method |
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