Center twisting type ultra-weak fiber bragg grating temperature and humidity strand

Abstract

The utility model relates to a center twisting type ultra-weak fiber bragg grating temperature and humidity stranded yarn, which adopts a humidity ultra-weak fiber bragg grating array, the temperature ultra-weak fiber bragg grating array and Kevlar fibers are combined to wrap a spiral armor tube, and then a metal wire braid layer is braided along the axial direction to form a temperature and humidity intelligent monofilament; the temperature and humidity intelligent monofilament serves as a center filament and is twisted with the six stainless steel wires to form a cable shape, and the temperature and humidity stranded filament of the ultra-weak fiber grating is manufactured. According to the utility model, the long-distance temperature and humidity ultra-weak fiber grating array is adopted to monitor temperature and humidity, temperature compensation is facilitated, temperature and humidity changes can be quickly responded, the filamentation porosity is large, the response speed is high, the mechanical strength is high, the adaptability is strong, and subsequent processing is facilitated.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the engineering monitoring technical field, especially relate to a center twist formula ultra-weak fiber grating temperature and humidity stock silk. BACKGROUND

[0002] In the monitoring of large bridges, optical fiber sensors have become the ideal choice for long-term monitoring of bridge structures due to their small size, light weight, high sensitivity, strong anti-electromagnetic interference ability, and other advantages. However, the application of traditional steel wire type optical fiber sensors in bridge monitoring still faces several challenges, especially in humidity sensing. The porosity of the sensor has a significant impact on its performance. Low porosity can lead to poor exchange efficiency of temperature and humidity between the sensor and the external environment, thereby affecting the accuracy and real-time performance of the measurement. Although increasing the porosity can improve the environmental response capability of the sensor, it often leads to a decrease in the strength of the steel pipe, thereby affecting the reliability of the overall structure. In addition, in order to improve the strength of the steel pipe, higher cost materials are usually required, which not only increases the production cost, but also makes the manufacturing process more complex, limiting large-scale production and application.

[0003] In response to this, Zhang Yibo et al. in their utility model patent with publication number CN114485451A, a high-precision fiber grating stress and strain sensor, proposed a scheme to improve precision through complex mechanical structure and heat insulation device. However, the manufacturing process of this scheme is complex, involving the installation, adjustment of multiple components, and the use of inert gas, etc. The production process is cumbersome and not conducive to multi-parameter monitoring of fiber grating sensors. In addition, the compressive and tensile strength of the sensor is not ideal, especially in complex working environments, the strength of the mechanical structure may not be sufficient to ensure long-term stability. Zhang Hong et al. in their utility model patent with publication number CN217358614U, a digital steel wire for measuring cable structure temperature and humidity in full range, proposed an improved fiber sensor structure, but this utility model uses a steel pipe design with low porosity, which is not conducive to full temperature and humidity exchange with the external environment. At the same time, to improve the temperature and humidity exchange effect, the excessive perforation of the outer sleeve pipe structure may weaken the overall strength of the sensor. In addition, Zhang Dongyu et al. in their patent with publication number CN217358614U, a temperature and humidity self-sensing bridge main cable intelligent steel wire fiber sensor and its design and application method, although the manufacturing process has been further optimized, improving the manufacturing efficiency of the sensor, but reducing the safety during the manufacturing process. UTILITY MODEL CONTENTS

[0004] The utility model discloses a center twist formula ultra-weak fiber grating temperature and humidity strand silk to solve the low safety in the manufacturing process, the complex manufacturing process, the low porosity and the single detection parameter of prior art existing problem. The utility model discloses through the innovative structure design, realizes the multi -parameter monitoring of stress strain, temperature, humidity while keeping high porosity, has improved the strength of sensor significantly, and has simplified the manufacturing process. The utility model discloses adopt ultra-weak fiber grating sensing technology, not only can realize accurate temperature and humidity monitoring under complex environment, also possesses durability and stability, is applicable to long -term bridge structure monitoring. Meanwhile, the manufacturing process of the utility model is simple and efficient, reduces production cost, has the potential of large -scale popularization and application to provide a reliable and economic solution for bridge monitoring field.

[0005] The utility model discloses a center twist formula ultra-weak fiber grating temperature and humidity strand silk to solve the low safety in the manufacturing process, the complex manufacturing process, the low porosity and the single detection parameter of prior art existing problem. The utility model discloses through the innovative structure design, realizes the multi -parameter monitoring of stress strain, temperature, humidity while keeping high porosity, has improved the strength of sensor significantly, and has simplified the manufacturing process. The utility model discloses adopt ultra-weak fiber grating sensing technology, not only can realize accurate temperature and humidity monitoring under complex environment, also possesses durability and stability, is applicable to long -term bridge structure monitoring. Meanwhile, the manufacturing process of the utility model is simple and efficient, reduces production cost, has the potential of large -scale popularization and application to provide a reliable and economic solution for bridge monitoring field.

[0006] The humidity ultra-weak fiber grating array, the temperature ultra-weak fiber grating array and the Kevlar fiber are bundled and wrapped the spiral armored pipe, and then the metal wire braiding layer is braided along the axial direction to form a temperature and humidity intelligent monofilament.

[0007] Preferably, the humidity ultra-weak fiber grating array is made of a fine-diameter ultra-weak fiber grating coated with ordinary polyimide once and humidity-sensitive polyimide material twice.

[0008] Preferably, the coating thickness of the ordinary polyimide and the humidity-sensitive polyimide material is 10 um.

[0009] Preferably, the temperature ultra-weak fiber grating array is prepared by coating the ultra-weak fiber grating with an acrylic coating once.

[0010] Preferably, the Kevlar fiber is a high-strength polyamide fiber with a diameter of 50 um, which is a continuous filament and does not break or tangle during the bundling process.

[0011] Preferably, the spiral armored pipe has a wall thickness of 0.25 mm and is formed by spirally winding a high-strength steel strip with a pitch of 3 mm. The metal wire braiding layer is braided by stainless steel wires with a diameter of 0.2 mm to 0.3 mm to improve the tensile performance of the spiral armored pipe. The wall thickness of the spiral armored pipe is 0.12 mm, and the spiral armored pipe is formed by spirally winding a stainless steel strip with a pitch of 3 mm.

[0012] Preferably, the humidity ultra-weak fiber grating array and the temperature ultra-weak fiber grating array have a diameter of not more than 0.25 mm, the grating pitch of the grating is 0.1 m-1 m, the center wavelength of the grating is alternately inscribed at 1550 nm and 1548 nm, the grating type is an ultra-weak grating, the grating manufacturing process is lossless inscription, and the grating coating layer is lossless.

[0013] In a second aspect, the utility model provides a kind of application method of center twisted ultra-weak fiber grating temperature and humidity strand, specifically comprising the following steps:

[0014] Step one, Kevlar fiber, humidity ultra-weak fiber grating array and temperature ultra-weak fiber grating array are combined, then spiral armoured tube is wrapped, and then axial braiding metal wire braiding layer is woven to form temperature and humidity intelligent monofilament;

[0015] Step two, temperature and humidity monofilament is twisted six stainless steel wires as center wire, and is made into ultra-weak fiber grating array temperature and humidity strand;

[0016] Step three, ultra-weak fiber grating array temperature and humidity strand is made into cable strand as center wire with other 90 high-strength stainless steel wires, and is poured into anchor head to be made into intelligent cable strand;

[0017] Step four, the intelligent cable strand is hung up using two traction belts, so that the intelligent cable strand is hung on traction cable without generating larger bending amplitude, so as to protect the intelligent temperature and humidity sensing strand of the ultra-weak fiber grating in the process of hanging cable, the intelligent cable strand is pulled by the above-mentioned mode, and becomes part of bridge main cable in anchor;

[0018] Step five, other ordinary cable strands are installed in sequence through traction cable using cable gripper, and bridge main cable is composed of one intelligent cable strand and other ordinary cable strands;

[0019] Step six, the bridge main cable that has been installed is tension calibrated, and tension of all cable strands is measured to ensure that each cable strand is stressed evenly, especially the stress condition of intelligent cable strand;Through the sensor system of the intelligent temperature and humidity sensing strand of the ultra-weak fiber grating, preliminary collection and calibration of temperature and humidity data are carried out, to ensure that the sensitivity and accuracy of the sensor system meet the design requirements.

[0020] Compared with prior art, the center twisted ultra-weak fiber grating temperature and humidity strand provided by the utility model has the following beneficial effects:

[0021] (1) high porosity, fast response speed and high mechanical strength

[0022] The long-distance temperature and humidity ultra-weak fiber grating array is adopted to monitor temperature and humidity, temperature compensation is facilitated, and the temperature and humidity can be quickly responded; the sensing fiber is wrapped with spiral Kevlar and metal woven structure, has large porosity, and is twisted around the central stainless steel wire, so that the temperature and humidity exchange with the outside environment is facilitated, and real-time and accurate monitoring of the temperature and humidity data is ensured; the Kevlar fiber is introduced and combined with the sensing fiber, the combined fiber can well avoid local excessive stretching; the spiral Kevlar is woven with metal wires, and the tensile strength of the spiral armor tube is improved.

[0023] (2) Strong adaptability, facilitating subsequent processing

[0024] The steel wire twisting structure can be directly stretched in the cable, and the adaptability and stability of the sensor in a complex environment are significantly improved. The outer woven layer can prevent the temperature and humidity intelligent monofilament from being squeezed out of the groove, and adapt to the working conditions of the cable and the hanging cable.

[0025] (3) Simple structure

[0026] The beam processing adopts the combination, armor and twisting processes which are widely used in traditional optical cable processing, and the production is mature and the manufacturing cost is low. The simple structure and production process greatly reduce the production cost, improve the manufacturing efficiency, have the potential for large-scale popularization and application, and further enhance the practicability and economy of the utility model in the bridge monitoring field. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 A structure schematic view of one embodiment of a center-twisted ultra-weak fiber grating temperature and humidity beam provided by the utility model.

[0028] Fig. 2 A structure schematic view of one embodiment of a domestic intelligent cable beam of a certain suspension bridge provided by the utility model.

[0029] Fig. 3 A structure schematic view of one embodiment of a domestic suspension bridge provided by the utility model.

[0030] In the above drawings: 1, bridge reinforced concrete structure; 2, main cable of the bridge; 21, ultra-weak fiber grating multi-parameter sensing intelligent beam; 211, humidity ultra-weak fiber grating array; 212, temperature ultra-weak fiber grating array; 213, Kevlar fiber; 214, spiral armor tube; 215, spiral armor woven layer; 216, outer layer stainless steel wire; 22, high-strength stainless steel wire. DETAILED DESCRIPTION

[0031] The utility model will be described in detail in combination with specific embodiments.

[0032] The embodiment provides a center-twisted ultra-weak fiber grating temperature and humidity beam, which comprises a center-twisted stainless steel wire, a humidity ultra-weak fiber grating array, a temperature ultra-weak fiber grating array, a Kevlar fiber and a spiral armor tube.Figs. 1-2 As shown in the figure, it comprises: a humidity ultra-weak fiber grating array 211, a temperature ultra-weak fiber grating array 212, a Kevlar fiber 213, a spiral armor pipe 214, a metal wire braiding layer 215, and a stainless steel wire 216.

[0033] The humidity ultra-weak fiber grating array 211, the temperature ultra-weak fiber grating array 212, and the Kevlar fiber 213 are combined to wrap the spiral armor pipe 214, and then the metal wire braiding layer 215 is braided along the axial direction to form a temperature and humidity intelligent single filament; the temperature and humidity intelligent single filament is twisted and combined with six stainless steel wires 216 as center wires to form a cord, and the cord is made into a temperature and humidity strand of the ultra-weak fiber grating.

[0034] In the above embodiment, the humidity ultra-weak fiber grating array 211 is made of a fine-diameter ultra-weak fiber grating which is once coated with ordinary polyimide and then twice coated with humidity-sensitive polyimide material.

[0035] The coating thickness of the ordinary polyimide and the humidity-sensitive polyimide material is 10 um.

[0036] In some embodiments, the temperature ultra-weak fiber grating array 212 is prepared by once coating an acrylic coating on an ultra-weak fiber grating.

[0037] In some preferred embodiments, the Kevlar fiber 213 is made of high-strength polyamide fiber with a diameter of 50 um, and is a continuous filament without breakage or entanglement during the beam combination process.

[0038] In another preferred embodiment, the spiral armor pipe 214 has a wall thickness of 0.25 mm and is made of high-strength steel strip spirally wound into a shape with a pitch of 3 mm; the metal wire braiding layer 215 is made of stainless steel wire with a diameter of 0.2 mm-0.3 mm and is used to improve the tensile properties of the spiral armor pipe; the wall thickness of the spiral armor pipe 214 is 0.12 mm.

[0039] In some embodiments, the diameter of the humidity ultra-weak fiber grating array 211 and the temperature ultra-weak fiber grating array 212 is not greater than 0.25 mm, the grating pitch of the grating is 0.1 m-1 m, the center wavelength of the grating is 1550 nm and 1548 nm, the grating type is ultra-weak grating, the grating manufacturing process is non-destructive writing, and the grating coating layer is non-damaged.

[0040] As another preferred embodiment of the present application, as shown in the figure, Figs. 1-3 The present embodiment provides an application method of the center-twisted ultra-weak fiber grating temperature and humidity strand, which comprises the following steps:

[0041] Step one, the Kevlar fiber silk 213, humidity ultra-weak fiber grating array 211 and temperature ultra-weak fiber grating array 212 are combined, then the spiral armor 214 is wrapped, and then the metal wire braided layer 215 is woven along the axial direction to form a temperature and humidity intelligent single filament;

[0042] Step two, the temperature and humidity single filament is twisted with six stainless steel filaments 216 to form an ultra-weak fiber grating array temperature and humidity strand;

[0043] Step three, the ultra-weak fiber grating array temperature and humidity strand 21 is combined with other 90 high-strength stainless steel filaments 22 to form a cable strand, and the anchor head is poured to form an intelligent cable strand;

[0044] Step four, the intelligent cable strand is lifted by two traction belts, so that the intelligent cable strand is hung on the traction cable without generating a large bending amplitude, thereby protecting the intelligent temperature and humidity sensing strand of the ultra-weak fiber grating during the hanging process, and the intelligent cable strand is pulled into the anchor to become part of the bridge main cable 2;

[0045] Step five, the other ordinary cable strands are installed in sequence through the traction cable by using the cable gripper, and the bridge main cable 2 is formed by one intelligent cable strand and other ordinary cable strands;

[0046] Step six, the tension of the installed bridge main cable 2 is calibrated, and the tension of all cable strands is measured to ensure that the forces of all cable strands are uniform, especially the force of the intelligent cable strand; then the bridge main cable 2 and the bridge reinforced concrete structure 1 jointly form a domestic suspension bridge; the sensor system of the intelligent temperature and humidity sensing strand of the ultra-weak fiber grating is used to collect and calibrate the temperature and humidity data, so that the sensitivity and accuracy of the sensor system meet the design requirements.

[0047] In the measurement process, when the external temperature changes, the ultra-weak fiber grating is affected by the thermal photoelectric effect and the thermal expansion of the acrylic coating, so that the center wavelength of the ultra-weak fiber grating changes, and the measurement of the external temperature change is realized; when the external humidity changes, the humidity sensitive polyimide material of the humidity ultra-weak fiber grating array 211 expands or shrinks, causing the center wavelength of the fine diameter ultra-weak fiber grating to change, and the change of the center wavelength of the fine diameter ultra-weak fiber grating is used to measure the change of the external humidity;

[0048] In the application of the utility model, the thickness of the humidity sensitive polyimide material or the non-humidity sensitive material coating can be adjusted to adjust the temperature and humidity measurement range and measurement accuracy of the sensor array.

[0049] Finally, it is explained that the above embodiments are only used to illustrate the technical solutions of the present application and are not limited. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the present application. The technical solutions of the present application should be covered in the scope of the claims of the present application.

Claims

1. A centrally twisted ultra-weak fiber grating temperature and humidity strand, characterized in that, Includes: a humidity-low-temperature fiber grating array (211), a temperature-low-temperature fiber grating array (212), Kevlar fiber (213), a spiral armor tube (214), a metal wire braided layer (215), and stainless steel wire (216); The humidity-low fiber grating array (211), the temperature-low fiber grating array (212), and the Kevlar fiber (213) are bundled together and wrapped around the spiral armor tube (214), and then the metal wire braided layer (215) is woven along the axial direction to form a temperature and humidity smart monofilament; the temperature and humidity smart monofilament is used as the central wire and twisted together with six stainless steel wires (216) to form a rope, which is used to make the temperature and humidity strand of the ultra-weak fiber grating; The Kevlar fiber (213) has a diameter of 50 μm, and the diameters of the humidity-weak fiber grating array (211) and the temperature-weak fiber grating array (212) are no greater than 0.25 mm.

2. The temperature and humidity strand of a center-twisted ultra-weak fiber grating according to claim 1, characterized in that, The spiral armor tube (214) has a wall thickness of 0.25mm and is formed by spiral winding of high-strength steel strip with a pitch of 3mm; the metal wire braided layer (215) is woven from stainless steel wire with a diameter of 0.2mm-0.3mm and is used to improve the tensile strength of the spiral armor tube. The spiral armor tube (214) has a wall thickness of 0.12mm and is formed by spiral winding of stainless steel strip with a pitch of 3mm.

3. The temperature and humidity strand of a center-twisted ultra-weak fiber grating according to claim 1, characterized in that, The grating has a pitch of 0.1m-1m, and the gratings with center wavelengths of 1550nm and 1548nm are alternately written. The grating type is an ultra-weak grating, and the grating manufacturing process is non-destructive writing. The grating coating layer is undamaged.

4. The temperature and humidity strand of a center-twisted ultra-weak fiber grating according to claim 1, characterized in that, The stainless steel wire (216) has the same diameter as the temperature and humidity smart monofilament.

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