CN114518140A - Temperature compensation type optical fiber intelligent gasket - Google Patents
Temperature compensation type optical fiber intelligent gasket Download PDFInfo
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- CN114518140A CN114518140A CN202210002112.5A CN202210002112A CN114518140A CN 114518140 A CN114518140 A CN 114518140A CN 202210002112 A CN202210002112 A CN 202210002112A CN 114518140 A CN114518140 A CN 114518140A
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- gasket
- temperature
- upper cover
- optical fiber
- strain
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 45
- 239000000835 fiber Substances 0.000 claims abstract description 26
- 238000005259 measurement Methods 0.000 claims abstract description 9
- 238000005452 bending Methods 0.000 claims description 2
- 238000006073 displacement reaction Methods 0.000 claims description 2
- 230000008859 change Effects 0.000 abstract description 12
- 238000012544 monitoring process Methods 0.000 abstract description 5
- 238000007789 sealing Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 description 3
- 239000000565 sealant Substances 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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- 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
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
-
- 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
- G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
- G01D11/30—Supports specially adapted for an instrument; Supports specially adapted for a set of instruments
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/30—Wind power
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention discloses a temperature compensation type optical fiber intelligent gasket, and belongs to the technical field of monitoring. The invention mainly comprises a gasket base and a gasket upper cover. A through hole is formed in the middle of the gasket base, and a groove is surrounded around the through hole; a positioning step is arranged on the periphery of the groove; the gasket upper cover is of a structure with bosses in the circumferential direction and a through hole in the center; the upper cover of the gasket is provided with a contact; after the gasket base and the gasket upper cover are combined, the lug boss of the gasket upper cover is required to be ensured not to be in contact with the step of the gasket base. Based on the fiber bragg grating strain measurement principle and the temperature compensation principle, the stress borne by the bolt is converted into the deformation of the elastic strain ring to generate strain through structural improvement, so that the wavelength of the fiber bragg grating sensor is changed, and meanwhile, the temperature sensor is used for compensating the temperature, so that the stress state of the bolt is monitored in real time. The invention can compensate the influence caused by the change of the external temperature and has the advantages of high precision, good sealing performance and strong practicability.
Description
Technical Field
The invention belongs to the technical field of monitoring, and particularly relates to a temperature compensation type optical fiber intelligent gasket for monitoring the stress state of a bolt.
Background
The bolt connection is widely applied to key force bearing structures such as civil transportation, large-scale buildings, aerospace, water, electricity, wind and electricity and the like. Bolt connection's pretightning force too big can lead to the bolt inefficacy, and too little then can lead to the not hard up of bolt to in long-term working process, receive factors such as vibration, power year influence, the bolt can appear not hard up, and the condition such as deformation brings very big potential safety hazard for structure or product, so the stress state to key bolt monitors and has profound meaning in the engineering.
However, due to the particularity of the bolted connection, it is difficult to detect the bolt by externally applying monitoring means. At present, the optimal detection means is to measure and calculate the pretightening force change by sensing the structural strain of a bolt or a gasket, but in the field of practical use scenes such as large-scale steel structures, aerospace and the like, the temperature environment of the gasket is greatly changed, and the optical fiber sensor still generates the change of wavelength after sensing the temperature change, so that the interference is generated on the test result, and the temperature compensation cannot be performed on the existing optical fiber intelligent gasket, so that the measurement precision is low. Therefore, it is necessary to design an optical fiber intelligent gasket capable of performing temperature self-compensation, so that the stress of the structure can be accurately monitored under different temperature environments.
Disclosure of Invention
In order to monitor the stress state of the bolt structure for a long time and consider the error of temperature change on the measurement result, the invention aims to provide the temperature compensation type optical fiber intelligent gasket. The invention can compensate the influence caused by the change of the external temperature and has the advantages of high precision, good sealing performance and strong practicability.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention discloses a temperature compensation type optical fiber intelligent gasket which mainly comprises a gasket base and a gasket upper cover. A through hole is formed in the middle of the gasket base, and a groove is surrounded around the through hole; a positioning step is arranged on the periphery of the groove; the gasket upper cover is of a structure with bosses in the circumferential direction and a through hole in the center; the upper cover of the gasket is provided with a contact; after the gasket base and the gasket upper cover are combined, the lug boss of the gasket upper cover is required to be ensured not to be in contact with the step of the gasket base.
The groove of the gasket base is fixedly provided with a supporting convex beam; the supporting convex beam is used for supporting the elastic ring; the optical fiber, the temperature sensor and the strain sensor are fixedly arranged on the surface of the supporting elastic ring and then integrally placed on the supporting convex beam of the groove; the contact is in contact with the supporting elastic ring.
The gasket is stressed to generate deformation displacement and is transmitted to the elastic ring by the contact, and the elastic ring is supported by the supporting convex beam and pressed down by the contact to form three-point stress bending.
The optical fiber strain sensor and the optical fiber temperature sensor are packaged on the same optical fiber.
And the supporting convex beam is provided with a U-shaped groove for facilitating the passing of optical fibers.
And the step of the gasket base is provided with a positioning groove for positioning the elastic ring.
The number of the contact and the supporting convex beam is at least three.
The number of strain sensors is at least four.
The invention discloses a working method of a temperature compensation type optical fiber intelligent gasket, which comprises the following steps:
based on the fiber grating strain measurement principle and the temperature compensation principle, the stress borne by the bolt is converted into the deformation of the elastic strain ring to generate strain through the stress deformation of the gasket base, so that the wavelength of the fiber grating sensor is changed, and meanwhile, the temperature sensor is used for compensating the temperature, so that the stress state of the bolt is monitored in real time.
Has the advantages that:
1. the invention discloses a temperature compensation type optical fiber intelligent gasket, which converts the stress deformation of the gasket into the change of the central wavelength of an optical fiber, thereby monitoring the stress state of the gasket.
2. The invention discloses a temperature compensation type optical fiber intelligent gasket, which is additionally provided with an optical fiber temperature sensor for temperature compensation, thereby realizing the self-compensation function under different temperature environments and improving the measurement precision.
3. According to the temperature compensation type optical fiber intelligent gasket disclosed by the invention, the sealant is coated in the groove formed by the joint surface of the gasket base and the gasket upper cover in a scraping manner, so that the external corrosive environment is sealed, and the durability and reliability of the gasket in a severe environment are improved.
Drawings
FIG. 1 is a schematic diagram of a temperature-compensated intelligent gasket for optical fiber according to the present invention;
FIG. 2 is a schematic view of a gasket base structure according to the present invention;
FIG. 3 is a schematic view of the elastic sheet, the optical fiber strain sensor and the optical fiber temperature sensor;
FIG. 4 is a schematic view of the upper cover of the gasket of the present invention;
FIG. 5 is a cloud graph of elastic strain stress of an optical fiber smart gasket;
FIG. 6 is a cloud graph of plastic strain stress for an optical fiber smart gasket.
In the figure; the optical fiber sensor comprises a gasket base 1, a gasket upper cover 2, a gasket 3, a sealant 4, a sealing plug, an optical fiber 5, a U-shaped groove 6, a fiber outlet hole 7, a supporting convex beam 8, a positioning groove 9, a positioning boss 10, an elastic ring 11, an optical fiber strain sensor 12, an optical fiber temperature sensor 13 and a contact 14.
Detailed Description
For a better understanding of the objects and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings and examples.
Example 1:
as shown in fig. 1 to 4, the temperature compensation type optical fiber intelligent gasket disclosed in this embodiment includes a gasket base 1, wherein a supporting convex beam 8, a U-shaped groove 6, and a positioning groove 9 are designed on the gasket base 1; the gasket upper cover 2 is provided with a contact 14; the optical fiber strain sensor comprises an elastic ring 11, wherein the elastic ring 11 is provided with a positioning boss 10, and an optical fiber strain sensor 12 is connected with an optical fiber temperature sensor 13 through an optical fiber 5 and arranged on the elastic ring 11; the optical fiber 5 passes through the sealing plug 4.
The hardness and the elastic modulus of the material of the upper gasket cover 2 are far higher than those of the gasket base 1, so that when the gasket is stressed, the deformation of the upper gasket cover 2 caused by stress is extremely small, and the main deformation of the gasket is caused by the stress deformation of the gasket base 1.
The elastic ring 11 is arranged between the supporting convex beam 8 and the contact 14, when the gasket is stressed to deform, the upper cover 2 of the gasket is caused to displace relative to the gasket base 1, so that the contact 14 generates downward pressure on the elastic ring 11 at four positions, and the supporting convex beam 8 applies supporting force on the elastic ring 11, so that three-point bending deformation is generated in four areas of the elastic ring 11.
The strain simulation analysis is carried out on the elastic ring 11, the stability of measurement is ensured, when the stress of the intelligent gasket reaches the maximum, the elastic ring 11 must be ensured to be in an elastic range, if the elastic ring 11 generates plastic strain, the material defect can be caused, uncontrollable factors are increased, and therefore when the stress load applies 200KN, the elastic strain and the plastic strain of the elastic body are respectively shown in a figure 5 and a figure 6, and it can be seen that the plastic strain of the elastic ring 11 becomes zero, which indicates that when the elastic ring 11 is stressed, the internal main components can not generate the plastic strain, namely, the elastic ring 11 is in the elastic range, the measurement range and the measurement precision of the intelligent gasket are ensured, and the practicability of the intelligent gasket structure is verified.
4 optical fiber strain sensors 12 are adhered to the elastic ring 11, and the optical fiber strain sensors 12 sense the deformation of the elastic ring 11 to generate strain and generate wavelength change, so that the stress change of the gasket at four angles is reflected.
The optical fiber strain sensor 12 is temperature compensated by the temperature value measured by the calibrated optical fiber temperature sensor 13. The specific compensation formula is as follows:
based on Maxwell classical equation, combining with fiber mode coupling theory, and using orthogonal relation of fiber grating transmission mode, the basic expression of Bragg grating reflection wavelength is obtained as follows:
λ＝2nΛ (1)
in the formula, lambda is the central wavelength of the grating; n is the effective refractive index of the fiber core; and Λ is the modulation period of the core refractive index. Differentiating two sides of the formula (1) to obtain:
dλ＝2Λdn+2ndΛ (2)
formula (1) is divided by formula (2) to obtain:
within the range of linear elasticity, have
Wherein ε represents strain.
Regardless of the waveguide effect, i.e., the effect of the axial deformation of the fiber on the refractive index, the refractive index of the fiber under uniaxial elastic deformation varies as follows:
in the formula, p11And p12Is the photoelastic constant; upsilon is Poisson's ratio, such that
From the formulae (3), (4), (5), it follows:
let alphaε＝λ(1-p)，αεSensitivity coefficient of strain and central wavelength variation
Δλ＝αεε (7)
The above equation is a mathematical relationship between strain and reflection wavelength change when the temperature is constant, i.e. the strain sensing principle of the FBG. For a fiber with a pure silica core, n is 1.456, p11＝0.121，p12θ is 0.270, θ is 0.17, and p is calculated to be 0.22. Taking commonly used fiber grating reflection wavelengths of 1545nm, 1550nm and 1555nm as examples, the calculated wavelength changes caused by each microstrain are 1.205pm, 1.209pm and 1.212pm respectively.
Temperature changes cause both changes in the refractive index of the fiber grating and changes in the pitch due to thermal expansion. Taking the derivative of equation (1) with respect to temperature T, regardless of the waveguide effect, one can obtain:
formula (1) in addition to the above formula, can give
Order to
Namely the thermo-optic coefficient;
i.e., coefficient of thermal expansion, can be obtained
Let alpha beT＝λ(α+ζ)，αTThe sensitivity coefficient of the fiber grating temperature sensing is obtained
Δλ＝αTΔT (11)
The above formula is the relationship between the wavelength variation of the fiber bragg grating and the temperature without the external force, i.e. the temperature sensing principle of the fiber bragg grating. For quartz optical fiber, the constant α is 0.55 × 10-6/℃、ζ＝4.67×10-6/℃。
The strain and temperature change are independent or only slightly disturbed, and when the temperature and the strain act together, the generated wavelength change can be expressed as
Δλ＝αεε+αTΔT (12)
Therefore, the rejection temperature variation should result in:
ε＝(Δλ-αTAT)/αs
in the formula, alphaεIs the strain sensitivity coefficient; alpha is alphaTThe temperature sensitivity coefficient is obtained by calibrating a standard incubator before the temperature sensor is installed.
After the gasket base 1 and the gasket upper cover 2 are connected, joint filling and sealing are carried out through sealant, so that the internal structure is isolated from the external corrosion environment.
The above detailed description is intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above detailed description is only exemplary of the present invention and is not intended to limit the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. A temperature compensation formula optic fibre intelligence gasket which characterized in that: mainly comprises a gasket base and a gasket upper cover; a through hole is formed in the middle of the gasket base, and a groove is surrounded around the through hole; a positioning step is arranged at the periphery of the groove; the gasket upper cover is of a structure with bosses in the circumferential direction and a through hole in the center; the upper cover of the gasket is provided with a contact; after the gasket base and the gasket upper cover are combined, a boss of the gasket upper cover is required to be ensured not to be in contact with a step of the gasket base;
the groove of the gasket base is fixedly provided with a supporting convex beam; the supporting convex beam is used for supporting the elastic ring; the optical fiber, the temperature sensor and the strain sensor are fixedly arranged on the surface of the supporting elastic ring and then integrally placed on the supporting convex beam of the groove; the contact is in contact with the supporting elastic ring.
2. The temperature-compensated fiber optic smart gasket of claim 1, wherein: the gasket is stressed to generate deformation displacement and is transmitted to the elastic ring by the contact, and the elastic ring is supported by the supporting convex beam and pressed down by the contact to form three-point stress bending.
3. The temperature-compensated fiber optic smart gasket of claim 1, wherein: the optical fiber strain sensor and the optical fiber temperature sensor are packaged on the same optical fiber.
4. The temperature-compensated fiber optic smart gasket of claim 1, wherein: and the supporting convex beam is provided with a U-shaped groove for facilitating the passing of the optical fiber.
5. The temperature-compensated fiber optic smart gasket of claim 1, wherein: and the step of the gasket base is provided with a positioning groove for positioning the elastic ring.
6. The temperature-compensated fiber optic smart gasket of claim 1, wherein: the number of the contact and the supporting convex beam is at least three.
7. The temperature-compensated fiber optic smart gasket of claim 1, wherein: the number of strain sensors is at least four.
8. A temperature-compensated fiber optic smart gasket as claimed in claim 1, 2, 3, 4, 5, 6 or 7, wherein: based on the fiber grating strain measurement principle and the temperature compensation principle, the stress borne by the bolt is converted into the deformation of the elastic strain ring to generate strain through the stress deformation of the gasket base, so that the wavelength of the fiber grating sensor is changed, and meanwhile, the temperature sensor is used for compensating the temperature, so that the stress state of the bolt is monitored in real time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210002112.5A CN114518140A (en) | 2022-01-04 | 2022-01-04 | Temperature compensation type optical fiber intelligent gasket |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210002112.5A CN114518140A (en) | 2022-01-04 | 2022-01-04 | Temperature compensation type optical fiber intelligent gasket |
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| CN114518140A true CN114518140A (en) | 2022-05-20 |
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09229807A (en) * | 1996-02-22 | 1997-09-05 | Hitachi Ltd | Pressure sensor |
| CN101630045A (en) * | 2009-07-28 | 2010-01-20 | 北京凯普林光电科技有限公司 | Device for improving spacial distribution of output beams output of multimode fibers |
| KR20130017820A (en) * | 2011-08-12 | 2013-02-20 | (주)엠이엘 텔레콤 | Wavelength tunable module containing a fiber bragg grating |
| CN203163914U (en) * | 2013-03-29 | 2013-08-28 | 武汉理工光科股份有限公司 | Fiber grating differential type dynamometer capable of achieving self temperature compensation |
| CN104567998A (en) * | 2014-12-12 | 2015-04-29 | 中国航空工业集团公司北京长城计量测试技术研究所 | Optical fiber Bragg grating sensing principle-based temperature-self-compensating intelligent bolt |
| CN104806761A (en) * | 2015-03-16 | 2015-07-29 | 武汉理工大学 | Fiber bragg grating sensor based intelligent flange gasket |
| WO2016121880A1 (en) * | 2015-01-29 | 2016-08-04 | 株式会社 東芝 | Temperature compensating element and light sensor system |
| CN110954259A (en) * | 2019-11-27 | 2020-04-03 | 同济大学 | Gasket sensor based on optical fiber microbend loss |
| CN113465799A (en) * | 2021-06-29 | 2021-10-01 | 中国船舶重工集团公司第七一五研究所 | Diaphragm type small-size fiber grating sensor for measuring high temperature and high pressure |
| CN113494955A (en) * | 2020-04-07 | 2021-10-12 | 江苏连动电气有限公司 | Fiber bragg grating acceleration sensing system for monitoring vibration of transformer |
-
2022
- 2022-01-04 CN CN202210002112.5A patent/CN114518140A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09229807A (en) * | 1996-02-22 | 1997-09-05 | Hitachi Ltd | Pressure sensor |
| CN101630045A (en) * | 2009-07-28 | 2010-01-20 | 北京凯普林光电科技有限公司 | Device for improving spacial distribution of output beams output of multimode fibers |
| KR20130017820A (en) * | 2011-08-12 | 2013-02-20 | (주)엠이엘 텔레콤 | Wavelength tunable module containing a fiber bragg grating |
| CN203163914U (en) * | 2013-03-29 | 2013-08-28 | 武汉理工光科股份有限公司 | Fiber grating differential type dynamometer capable of achieving self temperature compensation |
| CN104567998A (en) * | 2014-12-12 | 2015-04-29 | 中国航空工业集团公司北京长城计量测试技术研究所 | Optical fiber Bragg grating sensing principle-based temperature-self-compensating intelligent bolt |
| WO2016121880A1 (en) * | 2015-01-29 | 2016-08-04 | 株式会社 東芝 | Temperature compensating element and light sensor system |
| CN104806761A (en) * | 2015-03-16 | 2015-07-29 | 武汉理工大学 | Fiber bragg grating sensor based intelligent flange gasket |
| CN110954259A (en) * | 2019-11-27 | 2020-04-03 | 同济大学 | Gasket sensor based on optical fiber microbend loss |
| CN113494955A (en) * | 2020-04-07 | 2021-10-12 | 江苏连动电气有限公司 | Fiber bragg grating acceleration sensing system for monitoring vibration of transformer |
| CN113465799A (en) * | 2021-06-29 | 2021-10-01 | 中国船舶重工集团公司第七一五研究所 | Diaphragm type small-size fiber grating sensor for measuring high temperature and high pressure |
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Application publication date: 20220520 |