CN209802308U - Surface-mounted fiber grating strain sensor with temperature compensation - Google Patents
Surface-mounted fiber grating strain sensor with temperature compensation Download PDFInfo
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- CN209802308U CN209802308U CN201920688856.0U CN201920688856U CN209802308U CN 209802308 U CN209802308 U CN 209802308U CN 201920688856 U CN201920688856 U CN 201920688856U CN 209802308 U CN209802308 U CN 209802308U
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Abstract
The utility model discloses a surface-mounted fiber grating strain sensor with temperature compensation, which comprises a porous beam structure stainless steel sheet, an optical fiber, a strain grating, a temperature compensation grating and the like, wherein the strain grating and the temperature compensation grating are mutually connected in series and are inscribed on the same optical fiber; two hollowed-out elastic sheets which are respectively positioned at two sides of the strain grating are arranged in the middle of the porous beam structure stainless steel sheet; the two ends of the strain grating are provided with fixed points which can apply pretension and are respectively packaged and fixed on the two elastic sheets by low-temperature glass solder; the temperature compensation grating is fixed on one side of the strain grating in a loose state. The improved structure has the advantages of good weather resistance, good stability, smaller structural elastic modulus, better strain linearity, low insertion loss, good protection effect, high strain sensitivity and the like, solves the influence of temperature drift of the fiber grating strain sensor, and ensures the long-term consistency of strain, so the improved structure has high practical value in the monitoring of the surface strain of the civil engineering structure.
Description
Technical Field
The utility model relates to a fiber grating strain transducer field specifically is a take temperature compensation's SMD fiber grating strain transducer, but wide application in the strain monitoring on large-scale civil engineering structure surface.
Background
With the progress and development of society, more and more large civil engineering structures such as super bridges, super tunnels, super high-rise buildings and the like are emerging continuously, and in order to ensure the safe operation of the building structures, the structures need to be subjected to real-time strain monitoring. The existing monitoring mode mainly adopts a resistance strain gauge which is low in price, mature in technology and high in response speed, but the strain gauge has high requirements on a pasting process and is easy to paste failure, a pasting agent is easily affected by humidity and organic solvents, phenomena such as degumming and sensitive area corrosion occur, the phenomena cannot be recycled, meanwhile, a measurement result is interfered by electromagnetism, the service life is short, and the long-term monitoring is difficult to apply.
With the development of the optical fiber sensor technology, the optical fiber grating sensor is also rapidly developed in engineering application, mainly uses the optical fiber grating as a strain sensing unit, and has the characteristics of small volume, high sensitivity, corrosion resistance, electromagnetic interference resistance and the like. Moreover, at present, there are related patents for grating patch type strain sensors in China, for example, the published Chinese patent number is 201820879417.3, which is named as "a low-temperature glass solder packaged patch type strain sensor", but the structure has no temperature compensation function, so that the problem of temperature drift exists in practical application; the published Chinese patent application number is 201610275159.3, which is named as a patch type strain sensor, although the patch type strain sensor has the temperature compensation function, the sensor is packaged by glue, and has poor weather resistance, poor stability, larger structural elastic modulus and poorer strain linearity. In addition, the two fiber grating sensors have the following defects in practical application: firstly, the strain grating and the temperature compensation grating adopt a welding mode, so that the insertion loss is high and the protection effect is poor; and secondly, the fiber grating sensor has high rigidity, poor strain coupling with a measured structure and low strain sensitivity.
Disclosure of Invention
The utility model aims to solve the technical problem that overcome prior art's defect and provide resistant have the weather resistance good, stability is good, structure elastic modulus is less, the linearity of meeting an emergency is better, the insertion loss is low, the protection effect is good, the SMD fiber grating strain sensor of taking temperature compensation of advantages such as sensitivity height is met an emergency.
The technical problem of the utility model is realized through following technical scheme:
A surface-mounted fiber grating strain sensor with temperature compensation comprises a porous beam structure stainless steel sheet, an optical fiber, a strain grating and a temperature compensation grating, wherein two ends of the optical fiber respectively extend out of the porous beam structure stainless steel sheet to form a tail fiber, fiber outlet protective tubes fixed at two ends of the porous beam structure stainless steel sheet are sleeved on the tail fiber, and the strain grating and the temperature compensation grating are mutually connected in series and are engraved on the same optical fiber; two hollowed-out elastic sheets which are respectively positioned at two sides of the strain grating are arranged in the middle of the porous beam structure stainless steel sheet; two ends of the strain grating are provided with fixed points, and the two fixed points exert pretension and are respectively packaged and fixed on the two elastic sheets by low-temperature glass solder; the temperature compensation grating is fixed on one side of the strain grating in a loose state.
The porous beam structure stainless steel sheet is provided with three stainless steel sheets which are connected side by side, the strain grating is arranged on the porous beam structure stainless steel sheet in the middle, and the two elastic sheets are respectively arranged on two sides of the porous beam structure stainless steel sheet in the middle.
And two ends of each porous beam structure stainless steel sheet are respectively provided with a positioning hole, and the two ends of each porous beam structure stainless steel sheet are mounted on the surface of the structure to be measured by adhering or welding or connecting bolts in the positioning holes.
The middle of the porous beam structure stainless steel sheet is provided with a groove for embedding the optical fiber, the strain grating and the temperature compensation grating, and the width and the depth of the groove are both 2 mm.
One end of the temperature compensation grating is also provided with a fixed point which is fixed in the groove.
The strain grating and the temperature compensation grating adopt common micro-bending resistant optical fibers.
The thickness of the fiber grating strain sensor is 1mm, the fiber grating strain sensor is adhered to the surface of a steel structure, the width of the fiber grating strain sensor is 15mm, and the gauge length is 20 mm; the fiber bragg grating strain sensor is adhered to the surface of a concrete structure, the width of the fiber bragg grating strain sensor is 25mm, and the gauge length is 100 mm.
Compared with the prior art, the utility model mainly connects the strain grating and the temperature compensation grating in series and writes on the same optical fiber, thus avoiding welding, reducing insertion loss and improving protection effect; meanwhile, two elastic sheets respectively positioned at two sides of the strain grating are additionally arranged in the middle of the stainless steel sheet with the porous beam structure, then fixing points are arranged at two ends of the strain grating, pre-tension is applied to the fixing points at the two ends, and the two elastic sheets are respectively packaged and fixed by low-temperature glass solder; therefore, the structural design of the elastic sheet can reduce the rigidity of the fiber grating strain sensor, strengthen the strain coupling with the measured structure, and has higher strain sensitivity, and the fixed point of the strain grating is packaged by low-temperature glass solder, so that the fixing effect is better, the creep is avoided, and the long-term stability is good. The improved fiber grating sensor also has the advantages of good weather resistance, good stability, smaller structural elastic modulus, better strain linearity and the like, not only solves the influence of temperature drift of the fiber grating strain sensor, but also ensures the long-term consistency of strain.
Drawings
fig. 1 is a schematic structural diagram of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the drawings.
As shown in fig. 1, a tail fiber, 2, a fiber outlet protective tube, 3, a temperature compensation grating, 4, a strain grating, 5, a fixed point, 6, a stainless steel sheet with a porous beam structure, 7, a positioning hole, 8, an elastic sheet and 9, an optical fiber.
A patch type fiber grating strain sensor with temperature compensation is disclosed, as shown in figure 1, which is mainly composed of a porous beam structure stainless steel sheet 6, an optical fiber 9, a strain grating 4, a temperature compensation grating 3 and other structures, the thickness is 1mm, when the fiber grating strain sensor is adhered on the surface of a steel structure, the width is 15mm, and the gauge length is 20mm (without limitation to other dimensions); when the fiber bragg grating strain sensor is adhered to the surface of a concrete structure, the width of the fiber bragg grating strain sensor is 25mm, and the gauge length is 100mm (without limitation to other dimensions).
The porous beam structure stainless steel sheet 6 is provided with three connected side by side, is made into a hollow structure (without limitation to other materials) by adopting a 17-7PH material, has higher hardness and wear resistance compared with the common 304 stainless steel effect after quenching treatment, and also has certain corrosion resistance; two ends of each porous beam structure stainless steel sheet 6 are respectively provided with a positioning hole 7, and two ends of each porous beam structure stainless steel sheet 6 are mounted on the surface of the structure to be measured through pasting or welding or connecting bolts in the positioning holes 7.
A groove is arranged in the middle of the porous beam structure stainless steel sheet 6, the width and the depth of the groove are both 2mm, the optical fiber 9, the strain grating 4 and the temperature compensation grating 3 can be embedded and fixed, the strain grating 4 is arranged on the porous beam structure stainless steel sheet 6 in the middle, the two sides of the porous beam structure stainless steel sheet 6 in the middle are respectively provided with an elastic sheet 8, namely the two elastic sheets are respectively arranged on the two sides of the strain grating 4; the temperature compensation grating 3 is arranged on the stainless steel sheet 6 with the porous beam structure on the right side shown in figure 1 and can be fixed by adopting an adhesive or welding mode.
Strain grating 4 and temperature compensation grating 3 concatenate on an optic fibre 9, just the mutual concatenate of strain grating 4 and temperature compensation grating 3 and write on same optic fibre 9, so need not the butt fusion, the insertion loss is low, and the protection effect is better, and strain grating 4 and temperature compensation grating 3 all adopt ordinary anti microbending optic fibre moreover, and bending resistance is better.
two ends of the optical fiber 9 respectively extend out of the porous beam structure stainless steel sheet 6 and leave enough length as a tail fiber 1, the tail fiber is protected by a fiber outlet protection tube 2, and the fiber outlet protection tube is fixed at two ends of the porous beam structure stainless steel sheet 6 through a sealing structure adhesive.
The two ends of the strain grating 4 are respectively provided with a fixed point 5, the fixed points at the two ends exert pretension force and are respectively packaged and fixed on two elastic sheets 8 by low-temperature glass solder, and one end of the temperature compensation grating 3 is also provided with a fixed point, so the temperature compensation grating 3 can be fixed in a groove at one side of the strain grating 4 in a loose state, the temperature compensation grating 3 can supplement the influence of temperature factors on the strain grating 4, and the sensitivity and the consistency of the fiber grating strain sensor are ensured.
Meanwhile, the strain grating 4 packaged by the low-temperature glass solder has better fixing effect, no creep deformation and good long-term stability; and the porous beam structure stainless steel sheet 6 adopts a hollow elastic sheet 8 structure, so that the rigidity of the fiber grating strain sensor can be reduced, the strain coupling with a measured structure is enhanced, and the strain sensitivity is higher.
The utility model discloses an assembly process as follows:
Firstly, processing a porous beam structure stainless steel sheet 6 into a structure shown in fig. 1, and polishing and cleaning the porous beam structure.
Fixing points 5 at two ends of the strain grating 4 are packaged in grooves in the middle of the elastic sheet 8 by adopting low-temperature glass solders, the solders are dried, and certain pretension force needs to be applied in the packaging process of the strain grating 4.
The other end of the temperature compensation grating 3 is fixed in the groove of the porous beam structure stainless steel sheet 6, and the length of the temperature compensation grating is left with allowance to keep a loose state.
After the strain grating 4 and the temperature compensation grating 3 are fixed, 0.9mm fiber outlet protection tubes 2 penetrate through two ends of the tail fiber 1, and then the fiber outlet protection tubes are fixed at two ends of the porous beam structure stainless steel sheet 6 through sealing structure glue.
After the assembly is completed, calibrating the temperature/wavelength, the strain/wavelength coefficient of the strain grating 4 and the temperature/wavelength coefficient of the temperature compensation grating 3 respectively, and then compensating the temperature quantity of the strain grating 4 by measuring the change of the temperature wavelength and reversely deducing the temperature variation, so that the actual strain quantity can be obtained.
Sixthly, the surface mount type fiber grating strain sensor can be mounted on the surface of a structure to be measured in a welding, gluing and bolt fixing mode.
The use process of the fiber grating strain sensor comprises the following steps: one end of the digital sensor is fixed with a high-precision ball screw which can ensure tension transmission, the tension digital sensor is driven through the screw, the clamp tightly wrapping the optical fiber is connected onto the digital sensor, the tension is transmitted onto the digital sensor through rotating the screw, then the optical fiber on the clamp is driven to stretch, and when the tension of the digital sensor reaches a certain value, the optical fiber is pasted and fixed.
The utility model discloses structural design is simple, convenient to use, and measurement accuracy is high, and temperature compensation is effectual, and the linearity of meeting an emergency is good, has very high practical value in civil engineering structure surface strain monitoring, installs additional to the optic fibre of meeting an emergency on object surfaces such as concrete, steel structure body has characteristics such as the coupling is good, sensitivity is high, installation facility, has extensive application prospect.
The above description is only an embodiment of the present invention, and it should be understood by those skilled in the art that any structural design equivalent to this embodiment is included in the scope of the present invention.
Claims (7)
1. A patch type fiber bragg grating strain sensor with temperature compensation comprises a porous beam structure stainless steel sheet (6), an optical fiber (9), a strain grating (4) and a temperature compensation grating (3), wherein two ends of the optical fiber (9) respectively extend out of the porous beam structure stainless steel sheet (6) to form a tail fiber (1), and fiber outlet protective tubes (2) fixed at two ends of the porous beam structure stainless steel sheet (6) are sleeved on the tail fiber, and the patch type fiber bragg grating strain sensor is characterized in that the strain grating (4) and the temperature compensation grating (3) are mutually connected in series and are inscribed on the same optical fiber (9); two hollowed-out elastic sheets (8) which are respectively positioned at two sides of the strain grating (4) are arranged in the middle of the porous beam structure stainless steel sheet (6); fixing points (5) are arranged at two ends of the strain grating (4), and pretension force is applied to the fixing points at the two ends and is respectively packaged and fixed on the two elastic sheets (8) by low-temperature glass solder; the temperature compensation grating (3) is fixed on one side of the strain grating (4) in a relaxation state.
2. The patch type fiber grating strain sensor with temperature compensation according to claim 1, wherein the porous beam structure stainless steel sheet (6) is provided with three connected side by side, the strain grating (4) is arranged on the middle porous beam structure stainless steel sheet (6), and the two elastic sheets (8) are respectively arranged on two sides of the middle porous beam structure stainless steel sheet (6).
3. The surface mount fiber grating strain sensor with temperature compensation of claim 2, wherein the two ends of each porous beam structure stainless steel sheet (6) are respectively provided with a positioning hole (7), and the two ends of the porous beam structure stainless steel sheet (6) are mounted on the surface of the structure to be measured by adhering or welding or connecting bolts in the positioning holes (7).
4. The patch type fiber grating strain sensor with temperature compensation according to claim 1, wherein the porous beam structure stainless steel sheet (6) is provided with a groove in the middle for embedding the optical fiber (9), the strain grating (4) and the temperature compensation grating (3), and the width and depth of the groove are both 2 mm.
5. The patch type fiber grating strain sensor with temperature compensation of claim 4, wherein one end of the temperature compensation grating (3) is also provided with a fixing point, and the fixing point is fixed in the groove.
6. The surface-mounted fiber grating strain sensor with temperature compensation according to claim 1, wherein the strain grating (4) and the temperature compensation grating (3) are made of common microbend-resistant optical fibers.
7. The patch type fiber grating strain sensor with temperature compensation according to claim 1, wherein the thickness of the fiber grating strain sensor is 1mm, the fiber grating strain sensor is adhered to the surface of a steel structure, the width of the fiber grating strain sensor is 15mm, and the gauge length is 20 mm; the fiber bragg grating strain sensor is adhered to the surface of a concrete structure, the width of the fiber bragg grating strain sensor is 25mm, and the gauge length is 100 mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920688856.0U CN209802308U (en) | 2019-05-15 | 2019-05-15 | Surface-mounted fiber grating strain sensor with temperature compensation |
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| CN201920688856.0U CN209802308U (en) | 2019-05-15 | 2019-05-15 | Surface-mounted fiber grating strain sensor with temperature compensation |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111121716A (en) * | 2020-03-03 | 2020-05-08 | 南通装配式建筑与智能结构研究院 | Fiber grating static level |
| CN111504220A (en) * | 2020-05-01 | 2020-08-07 | 西安交通大学 | Fiber grating temperature/vibration/strain composite sensor and working method thereof |
| CN111504219A (en) * | 2020-05-01 | 2020-08-07 | 西安交通大学 | Few-mode fiber bragg grating three-parameter composite sensor and working method thereof |
| CN111537119A (en) * | 2020-04-22 | 2020-08-14 | 国网电力科学研究院有限公司 | High-precision fiber grating displacement meter with temperature compensation |
| CN113340223A (en) * | 2021-06-02 | 2021-09-03 | 桂林理工大学 | Fiber grating strain sensor with adjustable measuring range and preparation and use methods thereof |
| CN113503827A (en) * | 2021-06-09 | 2021-10-15 | 北京航天控制仪器研究所 | Device and method for measuring strain sensitivity of fiber bragg grating at ultralow temperature |
-
2019
- 2019-05-15 CN CN201920688856.0U patent/CN209802308U/en active Active
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111121716A (en) * | 2020-03-03 | 2020-05-08 | 南通装配式建筑与智能结构研究院 | Fiber grating static level |
| CN111537119A (en) * | 2020-04-22 | 2020-08-14 | 国网电力科学研究院有限公司 | High-precision fiber grating displacement meter with temperature compensation |
| CN111537119B (en) * | 2020-04-22 | 2022-06-14 | 国网电力科学研究院有限公司 | High-precision fiber grating displacement meter with temperature compensation |
| CN111504220A (en) * | 2020-05-01 | 2020-08-07 | 西安交通大学 | Fiber grating temperature/vibration/strain composite sensor and working method thereof |
| CN111504219A (en) * | 2020-05-01 | 2020-08-07 | 西安交通大学 | Few-mode fiber bragg grating three-parameter composite sensor and working method thereof |
| CN111504219B (en) * | 2020-05-01 | 2021-11-16 | 西安交通大学 | Few-mode fiber bragg grating three-parameter composite sensor and working method thereof |
| CN113340223A (en) * | 2021-06-02 | 2021-09-03 | 桂林理工大学 | Fiber grating strain sensor with adjustable measuring range and preparation and use methods thereof |
| CN113503827A (en) * | 2021-06-09 | 2021-10-15 | 北京航天控制仪器研究所 | Device and method for measuring strain sensitivity of fiber bragg grating at ultralow temperature |
| CN113503827B (en) * | 2021-06-09 | 2023-03-07 | 北京航天控制仪器研究所 | Device and method for measuring strain sensitivity of fiber bragg grating at ultralow temperature |
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