CN114061802A - Fiber grating clamp cable dynamometer - Google Patents
Fiber grating clamp cable dynamometer Download PDFInfo
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- CN114061802A CN114061802A CN202111373374.4A CN202111373374A CN114061802A CN 114061802 A CN114061802 A CN 114061802A CN 202111373374 A CN202111373374 A CN 202111373374A CN 114061802 A CN114061802 A CN 114061802A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
- G01L1/246—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre using integrated gratings, e.g. Bragg gratings
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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
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/165—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by means of a grating deformed by the object
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/0028—Force sensors associated with force applying means
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Abstract
The invention belongs to the technical field of cable force meters, and particularly relates to a fiber grating hoop cable force meter, which comprises: a clamping module comprising: the tensioning device comprises two jacket structures, cover plates, tensioning structures and jacket structure fastening bolts, wherein two sides of the two jacket structures are mutually connected through the two jacket structure fastening bolts, the top ends of the two jacket structures are mutually connected through the two cover plates, and the four tensioning structures are respectively arranged at four corners of the two jacket structures; the fiber grating strain gauge sensor comprises a fiber grating strain gauge sensor adapter sheet and a clamping module, wherein the fiber grating strain gauge sensor adapter sheet is fixed with the clamping module through a bolt. The fiber bragg grating hoop cable dynamometer calculates cable force by measuring the strain of the steel cable between the pair of hoops, the method is simple and efficient, and newly-built projects and existing projects can be monitored at any time; the method has the advantages of convenient installation, strong applicability, no damage to the surface of the steel cable and improvement on the defects of the current practical engineering cable force measuring method.
Description
Technical Field
The invention relates to the technical field of cable force meters, in particular to a fiber grating hoop cable force meter.
Background
The steel cable is a main bearing component of a space steel cable structure, and the whole engineering structure can be damaged when the cable force loss is serious, so that the monitoring and research on the stress state and the cable force evolution rule of the steel cable have important significance on the normal service function and the safety of the structure. The traditional cable force measuring method mainly comprises a magnetic flux method, a vibration frequency method and a resistance strain method, but can hardly meet the requirements of construction period monitoring, service period monitoring and real-time monitoring of cable force and monitoring without damaging a steel cable structure at the same time. Although both the magnetic flux method and the vibration frequency method can be used for monitoring in the construction period and the service period, both methods have certain limitations. The flux method is characterized in that a magnetic flux sensor is electrified to enable a steel cable to generate a longitudinal magnetic field to cause the sensor to generate induced electromotive force, the electromotive force can reflect the internal stress of the steel cable, special calibration needs to be carried out on site, the influence of temperature and an electromagnetic field is large, the cost is high, and time and labor are wasted; the vibration frequency method is that the vibration frequency of the steel cable is obtained by arranging an acceleration sensor on the steel cable, the hinged support of the two ends of the steel cable is limited, and the steel cable is not suitable for short cables or cables with higher rigidity, and then the method has large difficulty in formula derivation under complex boundary conditions, large workload of post data processing and is not beneficial to monitoring in an operation period; the resistance strain method is to stick strain gauges on the surface of the steel cable, calculate the cable force according to the relation between strain and stress, and only monitor the cable force in the construction period, and the strain gauges stuck on the surface are not suitable for protection, have low survival rate and are difficult to be applied to most projects.
Since the last 70 s, the optical fiber sensing technology using light waves as carriers has been developed rapidly. It has both sensing and transmission functions. According to the different characteristic parameters of modulated light wave in optical fiber, the optical fiber sensor is mainly divided into light intensity modulation type, phase modulation type, polarization state modulation type, frequency modulation type and wavelength modulation type. At present, in the field of structural health monitoring, a sensor based on a wavelength modulation type fiber bragg grating sensing technology is widely applied due to the advantages of light weight, corrosion resistance, interference resistance, integration of sensing and transmission and the like. Currently, the cable force measurement method related to the fiber grating sensing technology can be roughly divided into four methods: the cable head is provided with a sensor, a fiber grating sensing element is implanted in the steel cable, and the surface of the steel cable is adhered with the fiber grating sensing element or made into a feed-through force measuring ring and a clamp type cable dynamometer. The clamp cable dynamometer has the remarkable advantages by integrating factors such as construction difficulty, application stage, cost, influence degree on the steel cable and the like. However, in practical engineering, the steel wires between riggings are squeezed by tensioning the steel cables to cause a necking phenomenon, and meanwhile, the steel cables are not tightly twisted in the manufacturing process, the steel wires generate loose strength during working, and the twisting phenomenon of the steel cables is caused by load redistribution among the steel wires of each layer. The generation of the radial shrinkage and the torsion in the field can cause that the hoop cannot deform in cooperation with the steel cable, thereby causing the distortion of data acquired by the fiber grating sensor.
In patent CN 202110168663.4-a method and apparatus for measuring cable force of steel cable based on surface strain, a vibrating wire strain sensor is fixedly mounted on the surface of the measured cable through a rigid clamp, and the cable force is calculated according to the relationship between the measured surface strain of the steel cable and the overall strain, so that the quick and nondestructive mounting and real-time measurement can be realized; in patent CN 202010529449.2-a cable force monitoring device based on passive RFID strain sensor and a method for monitoring cable force and patent CN 201810782841.0-a cable force monitoring device based on fiber grating sensor, a positioning rod is used to fix a clamping component, which can realize remote non-contact measurement. However, the three methods cannot avoid the phenomenon of loose contact of the clamp due to the diameter shrinkage effect in the use process of the steel cable. In patent CN202010352074.7 — apparatus and method for measuring cable force of steel cable, the length between two cable hoops on the steel cable is accurately obtained by two length measuring devices, the cable hoop is normally installed on the steel cable, and can be monitored on the steel cable for a long time to accurately measure the cable force, and the apparatus is little affected by environmental factors and simple in calculation, but does not consider the effect of diameter shrinkage and torsion of the steel cable; in patent CN201811543797.4, a device for measuring the cable force of an external prestressed steel strand and a testing method thereof, a device is provided which can obtain the cable force only by simple mechanical testing without knowing material parameters, and the relative displacement between a fixed support and an anchor ear is controlled by welding the fixed support to the steel strand, but the welding process cannot realize flexible control of the support and the anchor ear. In the installation method of the CN 201010110769.0-fiber bragg grating strain sensor built in the cable, before the process of threading and heading the cable, the hoop is sleeved on the peripheral steel wire at the cable connecting cylinder part where the fiber bragg grating strain sensor is to be installed for pre-installation, and the tail fiber of the fiber bragg grating strain sensor is penetrated into a steel pipe channel reserved in the cable connecting cylinder and the anchor cup, so that the stability and reliability of the measuring device can be ensured, but the method has great influence on the manufacturing process of the steel cable.
The conventional cable force monitoring method, except for a hoop cable force meter method, cannot simultaneously meet the requirements of applicability of the cable force in both a construction period and a service period, reasonable manufacturing cost, simple construction, no damage to a steel cable structure and the like. In practical engineering, however, the steel wires between riggings are squeezed by tensioning the steel cables to cause the phenomenon of necking; the untight twisting in the process of manufacturing the steel cable can cause the steel wires to generate loose strength during working, so that load redistribution among the steel wires at each layer can generate torsion of the steel cable. The phenomenon of diameter shrinkage and torsion can cause that the clamp cannot cooperatively deform with the steel cable in the process of monitoring the cable force by using a clamp cable force meter method, so that data acquired by a sensor is distorted, and the accuracy of a monitoring result is greatly reduced.
In order to solve the above problems and satisfy the engineering application requirements, the novel clamp cable dynamometer structure should have the following characteristics: 1) simultaneously, the requirements of anti-radial shrinkage and anti-torsion are met; 2) the hoop can deform in cooperation with the steel cable; 3) the influence on the construction process of the steel cable is small or no influence; 4) the arrangement is convenient; 5) the fiber grating sensor does not need to be additionally heated for temperature compensation, namely, the temperature is self-compensated; 6) can reliably operate for a long time and has strong durability.
Disclosure of Invention
This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.
The present invention has been made in view of the above and/or other problems with existing fiber grating dynamometers.
Therefore, the invention aims to provide a fiber grating hoop cable dynamometer, which calculates cable force by measuring the strain of a steel cable between a pair of hoops, is simple and efficient, and can monitor newly-built projects and existing projects at any time; the method has the advantages of convenient installation, strong applicability, no damage to the surface of the steel cable and improvement on the defects of the current practical engineering cable force measuring method.
To solve the above technical problem, according to an aspect of the present invention, the present invention provides the following technical solutions:
a fiber grating clamp cable dynamometer, comprising:
a clamping module comprising: the tensioning device comprises two jacket structures, cover plates, tensioning structures and jacket structure fastening bolts, wherein two sides of the two jacket structures are mutually connected through the two jacket structure fastening bolts, the top ends of the two jacket structures are mutually connected through the two cover plates, and the four tensioning structures are respectively arranged at four corners of the two jacket structures;
the adapter sheet of the fiber grating strain gauge sensor is fixed with the clamping module through a bolt, and the adapter sheet of the fiber grating strain gauge sensor is fixed with the sensor through spot welding;
the anti-torsion guide rod is symmetrically arranged at four positions on two adjacent sides of the clamping module, and the joint of the anti-torsion guide rod and the clamping module is connected by a graphite copper sleeve.
As a preferable aspect of the fiber grating clamp cable dynamometer of the present invention, wherein: a tensioning arrangement comprising: pretension locking structure, pretension locking adjusting bolt, dish spring connector, belleville spring and spiral bullet pad, four pretension locking structure sets up the round hole department in the middle of two overcoat structures, and four pretension locking structure group becomes the ring structure, four pretension locking structure all is connected with belleville spring, belleville spring's one end is connected with pretension locking adjusting bolt through dish spring connector, spiral bullet pad is installed to pretension locking structure's inside wall.
As a preferable aspect of the fiber grating clamp cable dynamometer of the present invention, wherein: the disc spring connector is U-shaped, and one end of the disc spring is connected in series in a groove of the U-shaped structure of the disc spring connector.
As a preferable aspect of the fiber grating clamp cable dynamometer of the present invention, wherein: and two ends of the fiber grating strain gauge sensor are on the same axis and horizontal line.
As a preferable aspect of the fiber grating clamp cable dynamometer of the present invention, wherein: the installation process of the hoop cable dynamometer comprises the following steps:
s1: butting and splicing the two jacket structures;
s2: taking out all parts of the tensioning structure and splicing the parts into the tensioning structure;
s3: placing the tensioning structure formed in the second step into a clamping groove of the outer sleeve structure, and installing an outer sleeve structure fastening bolt;
s4: sleeving the outer sleeve structure on the steel cable, mounting the rest steps on the steel cable, and covering and fixing the cover plate;
s5: installing four anti-twist guide rods into the assembled structure in S4;
s6: assembling the other group of clamping modules and installing the other group of clamping modules at the other end of the anti-twisting guide rod;
s7: fixing the adapter plate of the fiber grating strain gauge sensor on the clamping module;
s8: and welding the fiber grating strain gauge sensor to the adapter plate to obtain the assembled structure.
As a preferable aspect of the fiber grating clamp cable dynamometer of the present invention, wherein: after the cable force meter is installed on the steel cable and the fiber Bragg grating sensor and the steel cable are fixed in parallel through the hoop, the cable force can be calculated out only by measuring the strain value of the steel cable between the hoops according to the Hooke's law as the elastic modulus and the effective metal section area of the steel cable are known parameters and based on the characteristic that the drift of the central wavelength of the fiber Bragg grating and the axial strain of an object to be measured are in a linear relation;
the cable force calculation steps are as follows:
s1: before the steel cable starts to be stretched, a novel hoop cable dynamometer is installed on the steel cable, the hoop cable dynamometer is in a zero state at the moment, and the light is recorded at the momentInitial wavelength lambda of fiber grating strain sensor0Initial wavelength of temperature compensation grating
S2: when the steel cable is stretched to a certain control force, the wavelength lambda of the sensor at the moment is collectedsWavelength of temperature compensation grating
S3: the calculation formula of the tensioning stage is as follows:
sensor wavelength variation delta lambda when stretching to a certain control forcesComprises the following steps: delta lambdas＝λs-λ0…………
Wavelength variation of the temperature compensation grating at this stage
Comprises the following steps:
………………
so that the wavelength variation caused only by strain at this stage
Comprises the following steps:
…………；
s4: according to the optical fiber sensing principle, the variation of the central wavelength value of the sensor is in direct proportion to the strain, and the proportionality coefficient
P is the effective photoelastic coefficient of the fiber grating, so the strain epsilon of the steel cable at the stagesComprises the following steps:
………；
s5: from Hooke's lawAt this stage, the change value F of the wire rope forcesComprises the following steps: fs＝εsE.A … … … …, where E is the elastic modulus MPa of the steel cord and A is the effective metal cross-sectional area m of the steel cord2。
Compared with the prior art: the effects of diameter shrinkage and torsion in the construction process of the steel cable can be well avoided through the design of the diameter shrinkage prevention structure and the torsion prevention structure, the good cooperation of the clamp, the steel cable and the sensor is realized through the pretightening force exerted by the disc spring and the fastening bolt to reinforce the structures of the clamp, the strain is well transmitted, and the cooperative deformation of the clamp and the steel cable is ensured; the novel hoop is obviously improved in comparison with the traditional hoop due to the addition of the anti-torsion guide rod, the accuracy of a bare cable force measurement result is greatly improved, the fiber grating hoop cable force meter calculates the cable force by measuring the cable strain between the paired hoops, and the method is simple and efficient and can monitor a newly-built project and an existing project at any time; the method has the advantages of convenient installation, strong applicability, no damage to the surface of the steel cable and improvement on the defects of the current practical engineering cable force measuring method.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail with reference to the accompanying drawings and detailed embodiments, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise. Wherein:
FIG. 1 is an isometric view of the present invention;
FIG. 2 is an isometric view of a clamp module of the present invention;
FIG. 3 is an isometric view of a tension structure of the present invention;
FIG. 4 is a graph showing the results of the cable force measurements of the present invention.
In the figure: the device comprises a steel cable 1, a clamping module 2, a fiber bragg grating strain gauge sensor 3, an anti-torsion guide rod 4, a jacket structure 5, a cover plate 6, a pre-tightening locking structure 7, a pre-tightening locking adjusting bolt 8, a jacket structure fastening bolt 9, a disc spring connector 10, a disc spring 11 and a spiral spring cushion 12.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and it will be apparent to those of ordinary skill in the art that the present invention may be practiced without departing from the spirit and scope of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
Next, the present invention will be described in detail with reference to the drawings, and in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the structure of the device are not enlarged partially according to the general scale for convenience of illustration, and the drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The invention provides a fiber bragg grating clamp cable dynamometer, which is used for calculating cable force by measuring the strain of a steel cable 1 between a pair of clamps, is simple and efficient, and can monitor newly-built projects and existing projects at any time; the method has the advantages of convenient installation, strong applicability, no damage to the surface of the steel cable 1 and improvement on the defects of the current practical engineering cable force measuring method.
Fig. 1-4 are schematic structural diagrams illustrating a first embodiment of a fiber grating clamp cable dynamometer according to the present invention, and referring to fig. 1-4, a fiber grating clamp cable dynamometer of the present embodiment includes a main body portion;
1. structural design of hoop cable dynamometer
The structural design of the hoop cable dynamometer comprises the following steps: the clamping module 2 comprises a pair of fiber grating strain gauge sensors 3 and an anti-twisting guide rod 4.
The clamping modules 2 are paired: the clamp cable dynamometer core structure adopts a modular design and contains a tensioning structure, can effectively and reliably clamp the steel cable 1 in a certain range, and is an important part for realizing the anti-radial shrinkage function.
Fiber grating strain gauge sensor 3: the temperature self-compensation function is realized, the sensor adapter plate is fixed with the clamping module 2 through bolts, and the adapter plate is fixed with the sensor in a spot welding mode. The existence of the adapter plate enables the two ends of the sensor to be on the same axis and the same horizontal line, and the reading of the sensor is accurate.
The anti-twisting guide rod 4: the two ends are symmetrically arranged at four positions, and the joint is integrally fixed by the graphite copper sleeve, so that the axial resistance can be reduced, and the occurrence of twisting is reduced.
2. Anti-radial shrinkage structure design
The taper sleeve thread fastening structure is limited by the actual working condition of the steel cable 1, the taper sleeve thread fastening structure in the traditional hoop is not suitable for the existing situation, and the split butt-joint structure is adopted for fastening design. The anti-radial shrinkage function is mainly realized by a tensioning structure contained in the clamping module 2. The clamping module 2 includes: the device comprises a pair of outer sleeve structures 5, a cover plate 6, a pre-tightening locking structure 7, a pre-tightening locking adjusting bolt 8 and an outer sleeve structure fastening bolt 9.
3. Design of tensioning structure
The tension structure includes: the device comprises a pre-tightening locking structure 7, a pre-tightening locking adjusting bolt 8, a disc spring connector 10, a pair of disc springs 11 and a spiral spring pad 12.
Disc spring 11: the compressed disc spring 11 is compressed and deformed until the compressed disc spring is flattened, the compressed disc spring is used as a live load in a stored energy mode, certain potential energy is stored, and when the compressed disc spring is loosened, the disc spring 11 releases partial potential energy to keep the pressure between the connection parts to meet the fastening requirement.
Disc spring connector 10: by connecting the disc springs in series through the U-shaped disc spring connector 10, a large preload can be provided in a short period of time using the paired disc springs.
Spiral spring washer 12: the spiral spring washer 12 acts as a pseudo-loose pretension. Because the change of the steel diameter generally takes the thinning as the main part, the traditional spiral spring cushion 12 is adopted for pre-tightening to ensure that the structure is further clamped through the pre-load, and the slippage phenomenon is prevented.
4. Working principle of optical fiber Bragg grating sensing system
The light and shade change of the fiber core represents the position of the fiber grating. A broadband light source is used for entering from one end of the optical fiber Bragg grating, and forward and backward light waves in the fiber core are coupled due to the periodic change of the refractive index. When the optical frequency of the wavelength satisfying the bragg condition is coupled into the backward transmission wave, a peak is formed in the reflection spectrum and a dip is formed in the transmission spectrum.
Example 1
The form of contrast experiment is passed through to this embodiment, adopts same demodulation appearance to test and data acquisition with novel clamp cable dynamometer and four kinds of traditional clamp cable dynamometers on same root cable, carries out the cable force measurement of diameter 75mm prestressing cable 1 in north-Hebei baoding giant force cable factory. Through calculation, in the embodiment, the disc spring with the outer diameter of 16mm, the inner diameter of 8.2mm and the thickness of 9mm is adopted, and after the height difference of 0.75 is compressed, the pretightening force of a single pair of disc springs can reach 1000N. The fiber grating sensor selected in the embodiment is an os3155 strain sensor produced by xingato, which is a fiber grating strain sensor with temperature compensation, the sensor substrate is made of stainless steel material, and is suitable for strain measurement of the surface of an outdoor steel structure, the fiber grating sensor plays a role in protecting an optical fiber in the installation process, and the grating is fixed on the stainless steel substrate material and is in a prestretched state.
Firstly, pre-tensioning is carried out after anchoring of the steel cable 1 is completed, the steel cable 1 is tensioned to 30% of the breaking force, then tensioning is stopped, a hoop cable dynamometer is installed, after installation is completed, tensioning is continued to 50% of the breaking force of the steel cable 1, then tensioning is stopped, and data are collected. The tensioning is carried out in stages, the breaking force of each 10 percent of the steel cable 1 is one stage, and the breaking force is added until 50 percent of the breaking force is added. Meanwhile, a pressure sensor on the tensile machine is adopted to read and collect the actual cable force of the steel cable 1, and the measured data of various hoop cable force meters are compared. The practical cable force data pairs obtained by each hoop cable force meter and the tensile machine, such as a seventh drawing, are obtained through sorting calculation, and the implementation result shows that the maximum error of the measured cable force value of the invention is 5%, and the error in the rest time is less than 3%, while the traditional hoop cable force meter has larger measured value due to larger torsion in the measuring process. This embodiment verifies the accuracy of the measurement data of the present invention, showing a significant advantage over conventional cable force meters.
While the invention has been described above with reference to an embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the various features of the disclosed embodiments of the invention may be used in any combination, provided that no structural conflict exists, and the combinations are not exhaustively described in this specification merely for the sake of brevity and resource conservation. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims (6)
1. A fiber grating clamp cable dynamometer, comprising:
clamping module (2) comprising: the tensioning device comprises outer sleeve structures (5), cover plates (6), tensioning structures and outer sleeve structure fastening bolts (9), wherein two sides of the two outer sleeve structures (5) are connected with each other through the two outer sleeve structure fastening bolts (9), the top ends of the two outer sleeve structures (5) are connected with each other through the two cover plates (6), and the four tensioning structures are respectively arranged at four corners of the two outer sleeve structures (5);
the optical fiber grating strain gauge sensor comprises an optical fiber grating strain gauge sensor (3), wherein an adapter sheet of the optical fiber grating strain gauge sensor (3) is fixed with a clamping module (2) through a bolt, and the adapter sheet of the optical fiber grating strain gauge sensor (3) is fixed with the sensor through spot welding;
the anti-torsion guide rod (4) is symmetrically arranged at four adjacent two sides of the clamping module (2), and the joint of the anti-torsion guide rod (4) and the clamping module (2) is connected by a graphite copper sleeve.
2. The fiber grating clamp dynamometer of claim 1,
a tensioning arrangement comprising: pretension locking structure (7), pretension locking adjusting bolt (8), dish spring connector (10), belleville spring (11) and spiral bullet pad (12), four pretension locking structure (7) set up the round hole department in the middle of two overcoat structures (5), and four pretension locking structure (7) constitute the ring structure, four pretension locking structure (7) all are connected with belleville spring (11), the one end of belleville spring (11) is connected with pretension locking adjusting bolt (8) through dish spring connector (10), spiral bullet pad (12) are installed to the inside wall of pretension locking structure (7).
3. A fiber grating clamp cable dynamometer according to claim 2, wherein the disk spring connector (10) is U-shaped, and one end of the disk spring (11) is connected in series in a groove of the U-shaped structure of the disk spring connector (10).
4. A fiber grating clamp dynamometer according to claim 1, wherein the two ends of the fiber grating strain gage sensor (3) are on the same axis and horizontal line.
5. The fiber grating clamp dynamometer of claim 1, wherein the clamp dynamometer is installed by the steps of:
s1: butting and splicing the two outer sleeve structures (5);
s2: taking out all parts of the tensioning structure and splicing the parts into the tensioning structure;
s3: placing the tensioning structure formed in the second step into a clamping groove of the outer sleeve structure (5), and installing an outer sleeve structure fastening bolt (9);
s4: sleeving the outer sleeve structure (5) on the steel cable (1), installing the rest steps on the steel cable (1), covering and fixing the cover plate (6);
s5: installing four anti-twist guide rods (4) into the assembled structure in S4;
s6: assembling the other group of clamping modules (2) and installing the clamping modules at the other end of the anti-twisting guide rod (4);
s7: fixing the adapter sheet of the fiber grating strain gauge sensor (3) on the clamping module (2);
s8: and welding the fiber grating strain gauge sensor (3) on the adapter plate to obtain the assembled structure.
6. The fiber Bragg grating hoop cable force meter as claimed in claim 1, wherein after the cable force meter is installed on the steel cable (1) and the fiber Bragg grating sensor and the steel cable (1) are fixed in parallel through the hoop, as the elastic modulus and the effective metal sectional area of the steel cable (1) are known parameters, according to hooke's law, only the strain value of the steel cable (1) between hoops is required to be measured, and then based on the characteristic that the drift of the central wavelength of the fiber Bragg grating and the axial strain of an object to be measured form a linear relation, the cable force can be calculated;
the cable force calculation steps are as follows:
s1: before the steel cable (1) starts to be stretched, a novel hoop cable dynamometer is installed on the steel cable (1), the hoop cable dynamometer is in a zero state at the moment, and the initial wavelength lambda of the fiber grating strain sensor at the moment is recorded0Initial wavelength of temperature compensation grating
S2: when the steel cable (1) is stretched to a certain control force, the wavelength lambda of the sensor at the moment is collectedsWavelength of temperature compensation grating
S3: the calculation formula of the tensioning stage is as follows:
sensor wavelength variation delta lambda when stretching to a certain control forcesComprises the following steps: delta lambdas＝λs-λ0…………
Wavelength variation of the temperature compensation grating at this stage
Comprises the following steps:
so that the wavelength variation caused only by strain at this stage
Comprises the following steps:
s4: according to the optical fiber sensing principle, the variation of the central wavelength value of the sensor is in direct proportion to the strain, and the proportionality coefficient
P is the effective photoelastic coefficient of the fiber grating, so the strain epsilon of the steel cable (1) at the stagesComprises the following steps:
s5: according to Hooke's law, the value F of the change in the force of the steel cable (1) at this stagesComprises the following steps: fs＝εsE.A … … … …, where E is the elastic modulus MPa of the steel cord (1) and A is the effective metal cross-sectional area m of the steel cord (1)2。
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102162760A (en) * | 2010-12-29 | 2011-08-24 | 中铁大桥局集团武汉桥梁科学研究院有限公司 | Cable force monitoring device for attached-type stay cable |
| CN108680291A (en) * | 2018-07-17 | 2018-10-19 | 大连理工大学 | A kind of cable force monitoring device based on fiber-optic grating sensor |
| CN112523430A (en) * | 2020-09-16 | 2021-03-19 | 广东省建筑设计研究院有限公司 | A fiber grating sensor wisdom cable for building cable structure |
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2021
- 2021-11-19 CN CN202111373374.4A patent/CN114061802A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102162760A (en) * | 2010-12-29 | 2011-08-24 | 中铁大桥局集团武汉桥梁科学研究院有限公司 | Cable force monitoring device for attached-type stay cable |
| CN108680291A (en) * | 2018-07-17 | 2018-10-19 | 大连理工大学 | A kind of cable force monitoring device based on fiber-optic grating sensor |
| CN112523430A (en) * | 2020-09-16 | 2021-03-19 | 广东省建筑设计研究院有限公司 | A fiber grating sensor wisdom cable for building cable structure |
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| Title |
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| 王旭泽: "《新型工程化光纤光栅索力监测用传感器的研制》", 《河南科学》, vol. 41, no. 6, 30 June 2023 (2023-06-30), pages 793 - 800 * |
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