WO2023155319A1

WO2023155319A1 - High-precision fibre bragg grating stress and strain sensor

Info

Publication number: WO2023155319A1
Application number: PCT/CN2022/094609
Authority: WO
Inventors: 郑一博; 苗银萍; 梁萍; 张磊; 王远; 朱占龙
Original assignee: 河北地质大学; 天津理工大学
Priority date: 2022-02-16
Filing date: 2022-05-24
Publication date: 2023-08-24
Also published as: CN114485451A; LU504704B1

Abstract

A high-precision fibre Bragg grating stress and strain sensor, comprising a strain sensor (1), a blocking device (2) and positioning devices (3), wherein the blocking device (2) is provided on an outer side of the strain sensor (1), the blocking device (2) comprises a heat insulation inner tube (201), the heat insulation inner tube (201) is provided on the outer side of the strain sensor (1), outer sides of the heat insulation inner tube (201) are slidably connected to heat insulation sleeves (202), the top end of the heat insulation inner tube (201) is fixedly connected to a fixing box (204), a piston plate (205) is slidably connected to an inner side of the fixing box (204), a rotating threaded shaft (206) is spirally connected to an inner side of the piston plate (205), the rotating threaded shaft (206) is rotatably connected to the fixing box (204), a front end of the fixing box (204) is in communication with a gas-intake tube (211), the bottom end of the fixing box (204) is in communication with a gas-output tube (212), fixing sleeves (4) are fixedly connected to both a left end and a right end of the outer side of the strain sensor (1), and the positioning devices (3) are provided on the outer sides of the fixing sleeves (4).

Description

A high-precision fiber grating stress-strain sensor

technical field

The invention relates to the technical field of fiber grating stress-strain sensors, in particular to a high-precision fiber grating stress-strain sensor.

Background technique

Fiber Bragg grating sensor is a kind of fiber optic sensor. The sensing process based on fiber Bragg grating is to obtain sensing information through the modulation of fiber Bragg wavelength by external physical parameters. It is a wavelength modulation fiber optic sensor. These sensors mainly include fiber Bragg grating strain Sensors, temperature sensors, acceleration sensors, displacement sensors, pressure sensors, flow sensors, liquid level sensors, etc. Fiber Bragg grating strain sensors are the most widely used and most mature fiber optic sensors in the engineering field. Strain directly affects the wavelength drift of fiber gratings , when the working environment is good or the structure to be tested requires fine sensors, people use bare fiber gratings as strain sensors directly pasted on the surface of the structure to be tested or buried inside the structure. It is very easy to damage in harsh working environments, so it needs to be packaged before it can be used. At present, the commonly used packaging methods mainly include substrate type, tube type, and tube-based clamping type at both ends. With the continuous development of society, for Fiber Bragg Grating stress-strain sensors are being used more and more, but some of the Fiber Bragg Grating stress-strain sensors used for geological disaster monitoring cannot well avoid the influence of external temperature on the Fiber Bragg Grating stress-strain sensors, thus affecting the optical fiber The accuracy of the grating stress-strain sensor in use, and when it is fixed, it is not convenient to stably fix it according to the flatness of the fixing surface, which affects the normal installation and use of the fiber grating stress-strain sensor.

technical problem

The purpose of the present invention is to provide a high-precision fiber grating stress-strain sensor to solve the problems raised in the above-mentioned background technology.

technical solution

In order to solve the above technical problems, the present invention provides the following technical solutions:

A high-precision optical fiber grating stress-strain sensor, including a strain sensor, a barrier device and a positioning device, the strain sensor is provided with a barrier device outside, the barrier device includes a heat-insulated inner tube, and the strain sensor is provided with a heat-insulated Inner pipe, the outer side of the heat-insulating inner pipe is slidably connected with a heat-insulating sleeve, the top of the heat-insulating inner pipe is fixedly connected with a fixed box, the inner side of the fixed box is slidably connected with a piston plate, and the inner side of the piston plate is spirally connected with a Rotate the threaded shaft, and the rotating threaded shaft is rotatably connected with the fixed box, the front end of the fixed box is connected with an air inlet pipe, the bottom end of the fixed box is connected with an air outlet pipe, and the left and right ends of the strain sensor are fixedly connected with fixed sleeves, so A positioning device is provided on the outside of the fixing sleeve.

Preferably, the inner end of the heat insulating sleeve is provided with an internal thread, and the outer end of the fixed sleeve is provided with an external thread, and the heat insulating sleeve is screwed with the fixed sleeve, and the outer end of the heat insulating sleeve is provided with a sealing ring , and the sealing ring is in close contact with the fixed sleeve, and the sealing ring is made of a rubber plate.

Preferably, a fixed ring is fixedly connected to the outer side of the piston plate, and the fixed ring is slidably connected to the fixed box, and the fixed ring is made of a rubber plate.

Preferably, a one-way valve is provided inside the air inlet pipe and the air outlet pipe, and the other end of the air outlet pipe communicates with the heat-insulated inner pipe.

Preferably, the bottom end of the heat-insulating inner tube is connected to a detection box through a connecting pipe, a first spring is fixedly connected to the inner side of the detection box, and a detection block is fixedly connected to the other end of the first spring, and the detection block is connected to the detection block. Box slide connection.

Preferably, the positioning device includes a bracket, a bracket is provided on the outside of the fixed sleeve, a fixed threaded shaft is screw-connected to the inner bottom end of the bracket, a fixed block is fixedly connected to the bottom end of the fixed threaded shaft, and the inner side of the fixed block The bottom end is rotatably connected with a rotating block through a rotating shaft, and the bottom end of the rotating block is rotatably connected with a positioning plate, and the outer side of the positioning plate is helically connected with a screw.

Preferably, the top of the bracket is rotatably connected with a positioning threaded shaft, and the positioning threaded shaft runs through the bracket, and the outside of the positioning threaded shaft is spirally connected with a first block, and the first block is slidably connected with the bracket, and the first block The block is engaged with the fixed sleeve.

Preferably, a pull rod is slidably connected to the top of the bracket, and the pull rod runs through the bracket, and a second block is fixedly connected to the bottom end of the pull rod, and the second block is slidably connected to the bracket, and the second block is engaged with the fixed sleeve A second spring is provided on the outside of the pull rod, and the second spring is fixedly connected to the second clamping block and the bracket.

Beneficial effect

Adopt above-mentioned technical scheme, produced technical effect is:

1. In the present invention, through the provided heat-insulating inner tube, heat-insulating sleeve, piston plate and detection block, when the device is used, the heat-insulating inner tube and the heat-insulating sleeve are set on the outside of the strain sensor, and then rotated The rotating threaded shaft is spirally connected with the piston plate, the inert gas is extracted through the inlet pipe, and then the inert gas is discharged between the strain sensor and the heat insulation pipe through the outlet pipe, and cooperates with the elastic force of the first spring on the detection block, which is very good for the device It plays the role of heat preservation and heat insulation, and avoids the influence of external temperature on the stress-strain sensor of the fiber Bragg grating, thereby improving the accuracy of the stress-strain sensor of the fiber grating;

2. In the present invention, through the provided first block, fixed threaded shaft and rotating block, when the device is used, the bracket and the fixed sleeve are connected together by the screw connection between the positioning threaded shaft and the first block, Then, by rotating the fixed block, the fixed threaded shaft and the bracket are spirally connected, and the positioning plate is rotated to rotate the rotating block and the fixed block, and the device can be stably fixed according to the flatness of the fixed surface, thus ensuring the stability of the fiber grating stress-strain sensor. Normal installation and use;

3. In the present invention, when the device is used, firstly pull the pull rod, cooperate with the elastic force of the second spring to connect the bracket with the second clamping block The fixed sleeves are connected together, and then the fixed thread shaft and the bracket are spirally connected by rotating the fixed block, and the positioning plate is rotated to rotate the rotating block and the fixed block, and the device can be stably fixed according to the flatness of the fixed surface, thus ensuring The normal installation and use of fiber grating stress strain sensor.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the first embodiment of the present invention;

Fig. 2 is the overall structure schematic diagram of the second embodiment of the present invention;

3 is a schematic cross-sectional structural view of the inner stent according to the first embodiment of the present invention;

Fig. 4 is a schematic cross-sectional structure diagram of an inner stent according to a second embodiment of the present invention;

Fig. 5 is the sectional structure schematic diagram of fixed box of the present invention;

Fig. 6 is a schematic cross-sectional structure diagram of the detection box of the present invention.

In the figure: 1-strain sensor, 2-blocking device, 201-heat insulation inner tube, 202-heat insulation sleeve, 203-sealing ring, 204-fixed box, 205-piston plate, 206-rotating threaded shaft, 207- Fixed ring, 208-detection box, 209-first spring, 210-detection block, 211-inlet pipe, 212-outlet pipe, 3-positioning device, 301-bracket, 302-fixed thread shaft, 303-fixed block, 304 -rotating block, 305-positioning plate, 306-screw, 307-positioning thread shaft, 308-first block, 309-pull rod, 310-second block, 311-second spring, 4-fixed sleeve.

Embodiments of the present invention

Example 1:

Please refer to Fig. 1, Fig. 3, Fig. 5 and Fig. 6, the present invention provides a kind of technical scheme:

A high-precision optical fiber grating stress-strain sensor, comprising a strain sensor 1, a barrier device 2 and a positioning device 3, the strain sensor 1 is provided with a barrier device 2 outside, the barrier device 2 includes a heat-insulating inner tube 201, and the strain sensor 1 is provided with a Insulation inner pipe 201, the outer side of heat insulation inner pipe 201 is slidingly connected with heat insulation sleeve 202, the inner end of heat insulation sleeve 202 is provided with internal thread, and the outer end of fixed sleeve 4 is provided with external thread, and heat insulation sleeve 202 and The fixed sleeve 4 is spirally connected, and the outer end of the heat insulation sleeve 202 is provided with a sealing ring 203, and the sealing ring 203 is in close contact with the fixed sleeve 4. The sealing ring 203 is made of a rubber material plate, which ensures heat insulation. The tightness between the mechanism and the fixed sleeve 4, the top of the heat-insulating inner tube 201 is fixedly connected with the fixed box 204, the inner side of the fixed box 204 is slidably connected with the piston plate 205, and the inner side of the piston plate 205 is spirally connected with the rotating thread shaft 206, and the rotating thread The shaft 206 is connected to the fixed box 204 in rotation, and the outer side of the piston plate 205 is fixedly connected with a fixed ring 207, and the fixed ring 207 is slidably connected to the fixed box 204. The fixed ring 207 is made of a rubber plate. This arrangement ensures that the piston The tightness between the plate 205 and the fixed box 204, the bottom end of the heat insulation inner tube 201 communicates with the detection box 208 through the connecting pipe, the inner side of the detection box 208 is fixedly connected with the first spring 209, and the other end of the first spring 209 is fixedly connected with the Detecting block 210, and detecting block 210 is slidably connected with detecting box 208, and this setting is convenient for determining whether the device leaks, and the front end of fixed box 204 is connected with air intake pipe 211, and the bottom end of fixed box 204 is connected with air outlet pipe 212, and the inside of air intake pipe 211 A one-way valve is provided on the inner side of the air outlet pipe 212, and the other end of the air outlet pipe 212 communicates with the heat-insulating inner pipe 201. This setting ensures the normal extraction and discharge of the inert gas. This setting has played a role in heat insulation for the device. The role of the external temperature on the FBG stress-strain sensor is avoided, thereby improving the accuracy of the FBG stress-strain sensor when used. The left and right ends of the strain sensor 1 are fixedly connected to the fixing sleeve 4, and the outside of the fixing sleeve 4 is provided with The positioning device 3, the positioning device 3 includes a bracket 301, the outside of the fixed sleeve 4 is provided with a bracket 301, the inner bottom of the bracket 301 is screw-connected with a fixed threaded shaft 302, the bottom of the fixed threaded shaft 302 is fixedly connected with a fixed block 303, and the inner side of the fixed block 303 The bottom end is rotatably connected with a rotating block 304 through a rotating shaft, the bottom end of the rotating block 304 is rotatably connected with a positioning plate 305, the outer side of the positioning plate 305 is spirally connected with a screw 306, and the top of the bracket 301 is rotatably connected with a positioning threaded shaft 307, and the positioning threaded shaft 307 runs through The bracket 301 is screw-connected with the first block 308 on the outside of the positioning threaded shaft 307, and the first block 308 is slidingly connected with the bracket 301, and the first block 308 is engaged with the fixed sleeve 4. This arrangement facilitates the positioning mechanism and The connection between the fixing sleeves 4 can stably fix the device according to the flatness of the fixing surface, thereby ensuring the normal installation and use of the fiber grating stress-strain sensor.

Workflow: When using the device, put the heat-insulating inner tube 201 and the heat-insulating sleeve 202 on the outside of the strain sensor 1, then glue the fixing sleeve 4 to the left and right ends of the outside of the strain sensor 1 with sealant, and then rotate the positioning threaded shaft 307, make the first block 308 and the fixed sleeve 4 clamp together, then turn the heat insulating sleeve 202 to make it screwed together with the fixed sleeve 4, then connect the air inlet pipe 211 with the check valve and the inert The gas container is connected, and then the rotating threaded shaft 206 is screwed with the piston plate 205 to draw the inert gas into the fixed box 204, and then the rotating threaded shaft 206 is reversed to pass through the gas outlet pipe 212 with a one-way valve. Press the inert gas into the position between the strain sensor 1 and the heat insulation tube. With the continuous pressure of the sucked gas, the detection block 210 will continue to stretch the first spring 209 and the detection box 208 to slide. When the detection block 210 When it is impossible to continue to slide down, just stop pressing the inert gas into the device, and then adjust the positioning mechanism according to the flatness of the installation point of the device. At this time, first turn the fixed block 303 to make the fixed threaded shaft 302 and the bracket 301 Screw connection to adjust the height difference, then turn the rotating block 304 according to the inclination of the installation surface to make it rotate with the fixed block 303, and then use the screw 306 and the screw connection of the positioning plate 305 to fix the device. , The operation is simple and convenient.

Example 2:

The same part as Embodiment 1 in Embodiment 2 will not be repeated, the difference is: Please refer to Fig. 2, Fig. 4, Fig. 5 and Fig. 6, the present invention provides a technical solution:

The positioning device 3 includes a bracket 301, the outer side of the fixed sleeve 4 is provided with a bracket 301, the inner bottom end of the bracket 301 is screw-connected with a fixed threaded shaft 302, the bottom end of the fixed threaded shaft 302 is fixedly connected with a fixed block 303, and the inner bottom end of the fixed block 303 passes through the rotating shaft Rotationally connected with a rotating block 304, the bottom of the rotating block 304 is rotatably connected with a positioning plate 305, the outside of the positioning plate 305 is screwed with a screw 306, the top of the bracket 301 is slidingly connected with a pull rod 309, and the pull rod 309 runs through the bracket 301, and the bottom end of the pull rod 309 is fixed. The second clamping block 310 is connected, and the second clamping block 310 is slidingly connected with the bracket 301, the second clamping block 310 is engaged with the fixed sleeve 4, and the outside of the pull rod 309 is provided with a second spring 311, and the second spring 311 is connected with the first The two clamping blocks 310 are fixedly connected to the bracket 301. This setting facilitates the connection between the positioning mechanism and the fixing sleeve 4. This setting can stably fix the device according to the flatness of the fixing surface, thereby ensuring the stress and strain of the fiber grating. Normal installation and use of the sensor.

Workflow: When using the device, glue the fixing sleeve 4 to the left and right ends of the strain sensor 1 with sealant, then pull the pull rod 309 to make the second block 310 compress the second spring 311, and then put the bracket 301 on the fixing sleeve 4 The outside makes the second clamping block 310 and the fixed sleeve 4 clamped together. After the clamping, when the device is positioned and installed, the positioning mechanism is first adjusted according to the flatness of the device mounting point. At this time, the fixed block 303 is first rotated. Screw the fixed threaded shaft 302 to the bracket 301 to adjust the height difference, then turn the rotating block 304 according to the inclination of the installation surface to rotate with the fixed block 303, and then through the screw 306 and the positioning plate 305 The screw connection can be used to fix the device, and the operation is simple and convenient.

In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above examples is only used to help understand the method and core idea of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that due to the limitation of literal expression, there are objectively unlimited specific structures. For those of ordinary skill in the art, without departing from the principle of the present invention, Several improvements, modifications or changes can also be made, and the above-mentioned technical features can also be combined in an appropriate manner; these improvements, modifications, or combinations, or the idea and technical solution of the invention are directly applied to other occasions without improvement, All should be regarded as the protection scope of the present invention.

Claims

A high-precision optical fiber grating stress-strain sensor, comprising a strain sensor (1), a blocking device (2) and a positioning device (3), characterized in that: the strain sensor (1) is provided with a blocking device (2), The barrier device (2) includes a heat-insulating inner tube (201), the strain sensor (1) is provided with a heat-insulating inner tube (201), and the outer side of the heat-insulating inner tube (201) is slidably connected with a heat-insulating sleeve Pipe (202), the top of the heat-insulating inner pipe (201) is fixedly connected with a fixed box (204), and the inner side of the fixed box (204) is slidably connected with a piston plate (205), and the inner side of the piston plate (205) is helical A rotating threaded shaft (206) is connected, and the rotating threaded shaft (206) is rotatably connected with the fixed box (204). An air outlet pipe (212) is communicated with it, and fixed sleeves (4) are fixedly connected to the left and right ends of the strain sensor (1), and a positioning device (3) is provided on the outside of the fixed sleeve (4).
A high-precision fiber grating stress-strain sensor according to claim 1, characterized in that: the inner end of the heat-insulating sleeve (202) is provided with an internal thread, and the outer end of the fixed sleeve (4) is provided with an outer thread. thread, and the heat insulation sleeve (202) is spirally connected with the fixed sleeve (4), and the outer end of the heat insulation sleeve (202) is provided with a sealing ring (203), and the sealing ring (203) is connected with the fixed sleeve (4) In close contact, the sealing ring (203) is made of a rubber plate.
A high-precision fiber grating stress-strain sensor according to claim 1, characterized in that: a fixed ring (207) is fixedly connected to the outer side of the piston plate (205), and the fixed ring (207) is connected to the fixed box (204 ) sliding connection, and the fixing ring (207) is made of a rubber plate.
A high-precision fiber grating stress-strain sensor according to claim 1, characterized in that: the inner side of the inlet pipe (211) and the inner side of the outlet pipe (212) are provided with one-way valves, and the outlet pipe (212) The other end communicates with the heat insulation inner pipe (201).
A high-precision fiber grating stress-strain sensor according to claim 1, characterized in that: the bottom end of the heat-insulated inner tube (201) is connected to a detection box (208) through a connecting pipe, and the detection box (208 ) is fixedly connected with a first spring (209), the other end of the first spring (209) is fixedly connected with a detection block (210), and the detection block (210) is slidingly connected with the detection box (208).
A high-precision fiber grating stress-strain sensor according to claim 1, characterized in that: the positioning device (3) includes a bracket (301), and the bracket (301) is provided on the outside of the fixing sleeve (4), The inner bottom end of the bracket (301) is spirally connected with a fixed threaded shaft (302), and the bottom end of the fixed threaded shaft (302) is fixedly connected with a fixed block (303), and the inner bottom end of the fixed block (303) passes through the rotating shaft A rotating block (304) is rotatably connected, and a positioning plate (305) is rotatably connected to the bottom end of the rotating block (304), and a screw (306) is spirally connected to the outside of the positioning plate (305).
A high-precision fiber grating stress-strain sensor according to claim 6, characterized in that: the top of the bracket (301) is rotatably connected with a positioning threaded shaft (307), and the positioning threaded shaft (307) runs through the bracket (301 ), the outside of the positioning threaded shaft (307) is screw-connected with a first clamping block (308), and the first clamping block (308) is slidingly connected with the bracket (301), and the first clamping block (308) and the fixed sleeve (4) Snap connection.
A high-precision fiber grating stress-strain sensor according to claim 6, characterized in that: a pull rod (309) is slidably connected to the top of the bracket (301), and the pull rod (309) runs through the bracket (301), the The bottom end of the pull rod (309) is fixedly connected with the second clamping block (310), and the second clamping block (310) is slidingly connected with the bracket (301), and the second clamping block (310) is engaged with the fixed sleeve (4) connected, the outside of the pull rod (309) is provided with a second spring (311), and the second spring (311) is fixedly connected to the second block (310) and the bracket (301).