CN115200482A - Short-gauge-length fiber bragg grating displacement sensor and using method thereof - Google Patents
Short-gauge-length fiber bragg grating displacement sensor and using method thereof Download PDFInfo
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- CN115200482A CN115200482A CN202210551526.3A CN202210551526A CN115200482A CN 115200482 A CN115200482 A CN 115200482A CN 202210551526 A CN202210551526 A CN 202210551526A CN 115200482 A CN115200482 A CN 115200482A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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Abstract
The invention belongs to the technical field of structural safety monitoring, and relates to a short-gauge-length fiber grating displacement sensor and a using method thereof. The device comprises an outer sliding block, an extension spring, a displacement sensing piece, a fiber bragg grating, a push rod, a compression spring, an inner sliding block and other main components. In the work, the movement of outer slider drives the change of extension spring tensile force, leads to displacement perception piece to produce deformation in coordination, and fiber grating produces corresponding deformation thereupon, converts the actual displacement volume of measurand through the offset that detects fiber grating resonance wavelength. The invention is characterized in that the measured direction and the stress deformation direction of the fiber bragg grating are not on the same straight line but are vertically distributed at 90 degrees, and the displacement is converted through a steering structure consisting of the inner sliding block and the outer sliding block, so that the size of the sensor in the measured direction is greatly reduced, and the problem of insufficient installation space of the traditional fiber bragg grating displacement sensor in the measured direction is solved. The invention has the advantages of simple structure, convenient installation, high measurement precision and good dynamic characteristic.
Description
Technical Field
The invention belongs to the technical field of structural safety monitoring, and relates to a short-gauge-length fiber bragg grating displacement sensor and a using method thereof.
Background
In recent years, the fiber grating displacement sensor has been widely used in various monitoring fields due to its advantages over electronic displacement sensors, such as anti-electromagnetic interference, corrosion resistance, stable long-term performance, and small long-distance transmission loss. However, most of the existing fiber grating displacement sensors have a large length in the measured direction, and when the measured gauge length of the measured object is short, the fiber grating displacement sensors face a dilemma that the fiber grating displacement sensors are difficult to install due to insufficient installation space.
Disclosure of Invention
In order to overcome the installation problem, the invention aims to provide the short-gauge-length fiber grating displacement sensor which is high in test precision, convenient to install and reliable to use.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the short-gauge-length fiber grating displacement sensor comprises a packaging cover 1, a packaging shell 2, a tail sleeve 3, an outer sliding block 4, an extension spring 5, a displacement sensing part 6, a fixing ring 7, a crimping ring 8, an armored optical cable 9, a loose sleeve 10, a fiber grating 11, a push rod 12, a compression spring 13, a flange nut 14 and an inner sliding block 15.
The packaging cover 1 is fastened on the packaging shell 2 through screws to form a cuboid sensor whole.
The top end of the packaging shell 2 is provided with two groups of structures which are the same in structure and are as follows: tail sleeve 3, solid fixed ring 7, crimping ring 8, armored cable 9, loose tube 10. The fixing ring 7 is fixedly connected with the top of the packaging shell 2 through threads, the fixing ring 7 is fixedly connected with the hollow armored optical cable 9 through the compression joint ring 8, the armored optical cable 9 is used for wrapping a loose tube 10 extending out of the outlet end of the fixing ring 7, and the top of the loose tube 10 is not wrapped by the armored optical cable 9. The lower end of the loose tube 10 penetrates through the fixing ring 7, and the loose tube 10 is internally coated with the fiber bragg grating 11. The tail sleeve 3 is sleeved outside the fixing ring 7 and covers the joint of the pressure joint ring 8 and the armored optical cable 9 to play a role in protection.
The packaging shell 2 is internally provided with an outer slide block 4, an extension spring 5, a displacement sensing piece 6 and an inner slide block 15. Outer slider 4, extension spring 5, displacement perception piece 6 locate inside below, middle part, the top of encapsulation casing 2 respectively, and extension spring 5's upper and lower both ends are connected with displacement perception piece 6, outer slider 4 respectively, promptly be connected through extension spring 5 between displacement perception piece 6 and the outer slider 4, pass through screw fastening connection between displacement perception piece 6 and the encapsulation casing 2. The displacement sensing piece 6 is of an annular structure, a groove is formed in the annular structure, the size of the groove is larger than the diameter of the fiber grating 11, and the groove is used for winding and placing the fiber grating 11. And an inclined plane is arranged on one surface of the outer sliding block 4 connected with the extension spring 5. The inner sliding block 15 is of a wedge-shaped structure and is provided with an inclined plane with the same inclined angle as the inclined plane of the outer sliding block 4, the inner sliding block 15 is arranged in a guide groove of the packaging shell 2, and the guide groove is arranged at the middle lower position inside the packaging shell 2. During operation, the inclined planes of the outer slider 4 and the inner slider 15 are completely attached, and the outer slider and the inner slider can move in the packaging shell for transmitting displacement in the vertical direction and reducing the size of the sensor in the measured displacement direction. The movement of the outer sliding block 4 drives the tensile force of the extension spring 5 to change, so that the displacement sensing piece 6 generates cooperative deformation, the fiber bragg grating 11 welded on the displacement sensing piece 6 also generates corresponding deformation, and the actual displacement of the measured object is converted by detecting the offset of the resonant wavelength of the fiber bragg grating 11.
The side surface of the packaging shell 2 is provided with a through hole, and the outer side of the side surface is provided with a push rod 12, a compression spring 13 and a flange nut 14. One end of the push rod 12 penetrates through the through hole and then is fastened with the inner slide block 15 through threads, and the other end of the push rod is sleeved with the compression spring 13 and then is fastened with the flange nut 14 through threads.
The fiber bragg grating 11 is arranged in a groove of the displacement sensing part 6, a grid region of the fiber bragg grating 11 is positioned in the middle of the annular structure of the displacement sensing part 6, and the fiber bragg grating 11 and the displacement sensing part 6 are welded and fastened by adopting a low-temperature glass welding process. After two ends of the fiber bragg grating 11 are sleeved with the loose tubes 10 and are respectively arranged in the hole grooves of the armored optical cable 9, the fiber bragg grating 11 and the loose tubes 10 are bonded through glue. The displacement sensor 6, the fiber grating 11 and the loose tube 10 which are connected together are integrally arranged in the packaging shell 2.
Further, the stiffness coefficient of the compression spring 13 is larger than that of the tension spring 5.
Furthermore, the displacement sensing member 6 has extremely high tensile strength, elastic limit, fatigue strength and good welding performance.
A use method of a short-gauge-length fiber grating displacement sensor comprises the following steps:
first, the push rod 12 of the short-gauge fiber grating displacement sensor is pressed against the object to be measured, and the compression spring 13 is ensured to have an appropriate amount of compression. When the object to be measured moves, the push rod 12 and the inner slide block 15 move along the direction to be measured under the combined action of the object to be measured and the compression spring 13.
Secondly, because the inclined planes of the outer slider 4 and the inner slider 15 are attached, when the inner slider 15 moves along the measured direction, the outer slider 4 moves in the direction perpendicular to the measured direction, and the extension spring 5 extends in the direction perpendicular to the measured direction.
Finally, the tensile force of the tension spring 5 changes, so that the displacement sensing member 6 generates cooperative deformation, the fiber bragg grating 11 welded on the displacement sensing member 6 also generates corresponding deformation, and the actual displacement of the measured object is converted by detecting the offset of the resonant wavelength of the fiber bragg grating 11.
The beneficial effects of the invention are as follows:
(1) The invention has the advantages of simple structure, convenient installation, high measurement precision and good dynamic characteristic.
(2) The invention has the innovation that the measured direction and the stress deformation direction of the fiber bragg grating are not on the same straight line but are vertically distributed at 90 degrees, and the displacement is converted through the steering structure consisting of the inner sliding block and the outer sliding block, so that the size of the sensor in the measured direction is greatly reduced, and the problem of insufficient installation space of the traditional fiber bragg grating displacement sensor in the measured direction is solved.
Drawings
Fig. 1 is a front view of a short-gauge fiber grating displacement sensor according to an embodiment of the present invention.
Fig. 2 is a top view of a tail sleeve with a packaging cover removed according to an embodiment of the present invention.
Fig. 3 is a top view of a hidden encapsulating cover, outer slide, provided by an embodiment of the present invention.
Fig. 4 is an isometric view of a displacement diverter structure provided by an embodiment of the present invention.
Fig. 5 is an isometric view provided by an embodiment of the invention.
Fig. 6 is an isometric view of a tail sleeve with the enclosure cover hidden, provided by an embodiment of the present invention.
In the figure: 1, packaging a cover; 2, packaging the shell; 3, sleeving a sleeve; 4, an outer sliding block; 5, extending a spring; 6 displacement sensing piece; 7, fixing a ring; 8, pressing and connecting the ring; 9 armored optical cable; 10 loosening the sleeve; 11 a fiber grating; 12, pushing a rod; 13 a compression spring; 14 a flange nut; 15 inner slide block.
Detailed Description
To achieve the object of the present invention, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings:
as shown in fig. 1, 2, 3 and 4, a short-gauge fiber grating displacement sensor includes: the optical fiber grating sensor comprises a packaging cover 1, a packaging shell 2, a tail sleeve 3, an outer sliding block 4, an extension spring 5, a displacement sensing part 6, a fixing ring 7, a pressure joint ring 8, an armored optical cable 9, a loose sleeve 10, an optical fiber grating 11, a push rod 12, a compression spring 13, a flange nut 14 and an inner sliding block 15.
The packaging cover 1 is fastened on the packaging shell 2 through screws to form a cuboid sensor whole, and the two tail sleeves 3 are installed at the top end of the packaging shell 2.
The top end of the packaging shell 2 is provided with two groups of fixing rings 7, a pressure joint ring 8 and an armored optical cable 9 in sequence side by side. Wherein the fixed ring 7 is fixedly connected with the packaging shell 2 through threads, and the armored optical cable 9 is fixedly connected with the fixed ring 7 through the compression joint ring 8. The tail sleeve 3 is sleeved on the outer side of the fixing ring 7, and covers the joint of the pressure joint ring 8 and the armored optical cable 9 to play a role in protection.
The packaging shell 2 is internally provided with an outer slide block 4, an extension spring 5, a displacement sensing piece 6 and an inner slide block 15. Wherein, the outer slide block 4 and the displacement sensing piece 6 are respectively connected with two ends of the extension spring 5, the displacement sensing piece 6 is fixedly connected with the packaging shell 2 by a screw, and the inner slide block 15 is arranged in a guide groove of the packaging shell 2; the outer slide block 4 is attached to the inclined plane of the inner slide block 15, the movement of the outer slide block 4 can drive the tensile force of the extension spring 5 to change, so that the displacement sensing piece 6 generates cooperative deformation, the fiber grating 11 welded on the displacement sensing piece 6 also generates corresponding deformation, and the actual displacement of the measured object is converted by detecting the offset of the resonant wavelength of the fiber grating 11.
The annular structure of the displacement sensing piece 6 is provided with a groove, and the size of the groove is larger than the diameter of the fiber grating 11.
Two ends of the fiber bragg grating 11 are sleeved with loose tubes 10 and are respectively arranged in the hole grooves of the armored optical cable 9, and the loose tubes 10 are bonded with the fiber bragg grating 11 through glue. The fiber grating 11 sleeved with the loose tube 10 is arranged in a groove of the displacement sensing piece 6, a grid region of the fiber grating 11 is positioned in the middle of an annular structure of the displacement sensing piece 6, and the fiber grating 11 and the displacement sensing piece 6 are welded and fastened by adopting a low-temperature glass welding process. The displacement sensor 6, the fiber grating 11 and the loose tube 10 which are connected together are integrally arranged in the packaging shell 2.
The outer end of the side surface of the packaging shell 2 is provided with a push rod 12, a compression spring 13 and a flange nut 14. One end of the push rod 12 is fastened with the inner slide block 15 through threads, and the other end of the push rod is sleeved with the compression spring 13 and fastened with the flange nut 14 through threads.
Further, the stiffness coefficient of the compression spring 13 is larger than that of the extension spring 5.
The working principle of the short-gauge-length fiber grating displacement sensor comprises the following steps:
1. the push rod 12 of the short-gauge fiber grating displacement sensor is pressed against the measured object, so that the compression spring 13 has proper compression amount.
2. When the object to be measured moves, the push rod 12 and the inner slide 15 move in the direction to be measured under the combined action of the object to be measured and the compression spring 13.
3. Because the inclined surfaces of the outer slide block 4 and the inner slide block 15 are attached, the outer slide block 4 can move in the direction perpendicular to the measured direction under the combined action of the inner slide block 15 and the extension spring 5.
4. The movement of the outer sliding block 4 can drive the tensile force of the extension spring 5 to change, so that the displacement sensing piece 6 generates cooperative deformation, the fiber bragg grating 11 welded on the displacement sensing piece 6 also generates corresponding deformation, and the actual displacement of the measured object is converted by detecting the offset of the resonant wavelength of the fiber bragg grating 11.
The above-mentioned embodiments only express the embodiments of the present invention, but not should be understood as the limitation of the scope of the invention patent, it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the concept of the present invention, and these all fall into the protection scope of the present invention.
Claims (3)
1. A short-gauge length fiber grating displacement sensor is characterized in that: the short-gauge-length fiber bragg grating displacement sensor comprises a packaging cover (1), a packaging shell (2), a tail sleeve (3), an outer sliding block (4), an extension spring (5), a displacement sensing piece (6), a fixing ring (7), a crimping ring (8), an armored optical cable (9), a loose sleeve (10), a fiber bragg grating (11), a push rod (12), a compression spring (13), a flange nut (14) and an inner sliding block (15);
the packaging cover (1) is fastened on the packaging shell (2) to form a cuboid sensor whole;
the top end of the packaging shell (2) is provided with two groups of structures which are the same in structure and are as follows: the cable comprises a tail sleeve (3), a fixing ring (7), a crimping ring (8), an armored cable (9) and a loose sleeve (10); the fixing ring (7) is fixed to the top of the packaging shell (2), the fixing ring (7) and the hollow armored optical cable (9) are fixedly connected through a compression joint ring (8) in a compression joint mode, the armored optical cable (9) is used for wrapping a loose tube (10) extending out of the outlet end of the fixing ring (7), and the top of the loose tube (10) is not wrapped by the armored optical cable (9); the lower end of the loose tube (10) penetrates through the fixing ring (7), and the loose tube (10) is internally coated with a fiber grating (11); the tail sleeve (3) is sleeved outside the fixing ring (7) and covers the joint of the crimping ring (8) and the armored optical cable (9) to play a role in protection;
an outer sliding block (4), an extension spring (5), a displacement sensing piece (6) and an inner sliding block (15) are arranged in the packaging shell (2); the outer sliding block (4), the extension spring (5) and the displacement sensing piece (6) are respectively arranged below, in the middle and above the interior of the packaging shell (2), the displacement sensing piece (6) is connected with the outer sliding block (4) through the extension spring (5), and the displacement sensing piece (6) is fixedly connected with the packaging shell (2) through screws; the displacement sensing piece (6) is of an annular structure, a groove is formed in the annular structure, the size of the groove is larger than the diameter of the fiber grating (11), and the groove is used for winding and placing the fiber grating (11); one side of the outer sliding block (4) connected with the extension spring (5) is provided with an inclined plane; the inner sliding block (15) is of a wedge-shaped structure and is provided with an inclined plane with the same inclined angle as the inclined plane of the outer sliding block (4), and the inner sliding block (15) is arranged in a guide groove of the packaging shell (2); the outer sliding block (4) is completely attached to the inclined plane of the inner sliding block (15), the movement of the outer sliding block (4) drives the tensile force of the tension spring (5) to change, so that the displacement sensing piece (6) generates cooperative deformation, the fiber bragg grating (11) fixed on the displacement sensing piece (6) generates corresponding deformation, and the actual displacement of the measured object is converted by detecting the offset of the resonant wavelength of the fiber bragg grating (11);
a through hole is formed in the side surface of the packaging shell (2), and a push rod (12), a compression spring (13) and a flange nut (14) are arranged on the outer side of the side surface; one end of the push rod (12) penetrates through the through hole and then is fastened with the inner slide block (15) through threads, and the other end of the push rod is sleeved with the compression spring (13) and then is fastened with the flange nut (14) through threads;
the fiber bragg grating (11) is arranged in a groove of the displacement sensing part (6), a grating area of the fiber bragg grating (11) is positioned in the middle of an annular structure of the displacement sensing part (6), and the fiber bragg grating (11) is fastened with the displacement sensing part (6); two ends of the fiber bragg grating (11) are sleeved with loose tubes (10) and are respectively arranged in the hole grooves of the armored optical cable (9), and the fiber bragg grating (11) and the loose tubes (10) are bonded through glue; the displacement sensing piece (6), the fiber bragg grating (11) and the loose tube (10) which are connected together are integrally arranged in the packaging shell (2).
2. The short-gauge fiber grating displacement sensor according to claim 1, wherein: the stiffness coefficient of the compression spring (13) is larger than that of the extension spring (5).
3. A method for using the short-gauge fiber grating displacement sensor according to claim 1 or 2, comprising the following steps:
firstly, a push rod (12) of a short-gauge-length fiber grating displacement sensor is pressed against a measured object, and when the measured object moves, the push rod (12) and an inner slide block (15) move along the measured direction under the combined action of the measured object and a compression spring (13);
secondly, because the outer sliding block (4) is attached to the inclined plane of the inner sliding block (15), when the inner sliding block (15) moves along the measured direction, the outer sliding block (4) moves in a direction perpendicular to the measured direction, and the extension spring (5) stretches in a direction perpendicular to the measured direction;
finally, the change of the tensile force of the tension spring (5) causes the displacement sensing piece (6) to generate cooperative deformation, the fiber grating (11) fixed on the displacement sensing piece (6) generates corresponding deformation, and the actual displacement of the measured object is converted by detecting the offset of the resonant wavelength of the fiber grating (11).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210551526.3A CN115200482A (en) | 2022-05-18 | 2022-05-18 | Short-gauge-length fiber bragg grating displacement sensor and using method thereof |
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| CN202210551526.3A CN115200482A (en) | 2022-05-18 | 2022-05-18 | Short-gauge-length fiber bragg grating displacement sensor and using method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116164660A (en) * | 2023-04-21 | 2023-05-26 | 安徽省七星工程测试有限公司 | Fiber bragg grating dynamic deflection monitor and monitoring method |
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- 2022-05-18 CN CN202210551526.3A patent/CN115200482A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116164660A (en) * | 2023-04-21 | 2023-05-26 | 安徽省七星工程测试有限公司 | Fiber bragg grating dynamic deflection monitor and monitoring method |
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