Ultra-weak fiber grating temperature and humidity sensing intelligent strand

Abstract

The utility model relates to an ultra-weak fiber bragg grating temperature and humidity sensing intelligent stranded wire, which is characterized in that a humidity ultra-weak fiber bragg grating array is adopted, the temperature ultra-weak fiber bragg grating array and Kevlar fibers are combined to wrap a spiral armor tube, and then a spiral armor braid layer is processed along the axial direction to form a temperature and humidity intelligent monofilament; the temperature and humidity intelligent monofilament and the five outer-layer stainless steel wires are twisted to form a center stainless steel wire, the center stainless steel wire and the five outer-layer stainless steel wires are twisted to form a cable shape, and then the strand woven layer is woven in the length direction of a cable body, so that the ultra-weak fiber grating temperature and humidity sensing intelligent strand is formed. 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 kind of super-weak fiber grating temperature and humidity sensing wisdom strand. 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, and strong anti-electromagnetic interference capability. 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, affecting the accuracy and real-time performance of the measurement. Although increasing porosity can improve the environmental response capability of the sensor, it often leads to a decrease in the strength of the steel pipe, which in turn affects 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 thermal insulation device. However, the manufacturing process of this scheme is complex, involving the installation, adjustment of multiple components, and the use of inert gas, making the production process tedious 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, excessive punching 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 kind of super-weak fiber grating temperature and humidity sensing wisdom strands for the deficiencies of prior art, to solve the problems of low safety in manufacturing process, complex manufacturing process, low porosity and single detection parameter in prior art.The utility model realizes the multi-parameter monitoring of stress and strain, temperature and humidity by innovative structure design, significantly improves the strength of sensor, and simplifies manufacturing process.The utility model uses super-weak fiber grating sensing technology, not only can realize accurate temperature and humidity monitoring in complex environment, but also has durability and stability, suitable for 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, thereby providing a reliable and economical solution for bridge monitoring field.

[0005] The utility model discloses a kind of super-weak fiber grating temperature and humidity sensing wisdom strands, comprising: humidity super-weak fiber grating array, temperature super-weak fiber grating array, kevlar fiber, spiral armoured pipe, spiral armoured braid, outer layer stainless steel wire, center stainless steel wire, strand braid layer;

[0006] The humidity super-weak fiber grating array, the temperature super-weak fiber grating array and the kevlar fiber are bundled and wrapped by the spiral armoured pipe, and the spiral armoured braid is wrapped outside the spiral armoured pipe to form a temperature and humidity intelligent monofilament;The temperature and humidity intelligent monofilament is twisted with five outer layer stainless steel wires and a center stainless steel wire into a cable, and is woven with a strand braid layer outside, and the center stainless steel wire is located at the geometric center of the temperature and humidity intelligent monofilament and the five outer layer stainless steel wires

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

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

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

[0010] Preferably, the kevlar fiber is made of high-strength polyamide fiber with a diameter of 50 um, and is a continuous filament without breaking or entangling during bundling.

[0011] Preferably, the spiral armoured braid is woven from stainless steel wires with a diameter of 0.2 mm, and is wrapped outside the spiral armoured pipe to prevent the spiral armoured pipe from being stretched beyond capacity.

[0012] Preferably, the strand braid layer is braided by stainless steel wires with a diameter of 0.2 mm to prevent the temperature and humidity intelligent monofilament from being separated from the other six stainless steel wires.

[0013] In a second aspect, the utility model provides an application method of the ultra-weak fiber grating temperature and humidity sensing intelligent strand, which specifically comprises the following steps:

[0014] Step one, wrap the temperature and humidity intelligent monofilament with the Kevlar fiber, and then wrap the spiral armor tube, and then braid the spiral armor braid layer along the axial direction to form the temperature and humidity intelligent monofilament;

[0015] Step two, twist the temperature and humidity intelligent monofilament with the five outer layer stainless steel wires and the center stainless steel wire to form a cable, and then braid the strand braid layer along the length direction of the cable body as a protective layer to form the ultra-weak fiber grating temperature and humidity sensing intelligent strand;

[0016] Step three, bundle the ultra-weak fiber grating temperature and humidity sensing intelligent strand with the other 90 high-strength stainless steel wires to form a cable strand, and then vertically suspend the cable strand through the anchoring platform, and then pour the zinc-magnesium alloy solution into the anchor head to form the intelligent cable strand;

[0017] Step four, lift the intelligent cable strand with two traction belts, so that the intelligent cable strand is hung on the traction cable without generating a large bending amplitude, thereby protecting the ultra-weak fiber grating temperature and humidity sensing intelligent strand during the hanging process, and entering the anchor to become a part of the main cable of the bridge;

[0018] Step five, use the cable gripper to install other ordinary cable strands through the traction cable in sequence, and the intelligent cable strand and the other ordinary cable strands jointly form the main cable of the bridge; when pouring the cable strand, the copper pipe is used to wrap the ultra-weak fiber grating temperature and humidity sensing intelligent strand to isolate the high temperature during pouring and avoid damaging the ultra-weak fiber grating temperature and humidity sensing intelligent strand during pouring the anchor head.

[0019] Compared with the prior art, the ultra-weak fiber grating temperature and humidity sensing intelligent strand has the following beneficial effects:

[0020] Large porosity, fast response speed, and high mechanical strength

[0021] The long-distance temperature and humidity ultra-weak fiber grating array is used to monitor the temperature and humidity, temperature compensation is facilitated, the change of temperature and humidity can be quickly responded, the sensing optical fiber is wrapped with the spiral Kevlar and the metal braid structure, has a large porosity, and is twisted around the center stainless steel wire, so that the temperature and humidity exchange with the external environment is facilitated, and the real-time and accurate monitoring of the temperature and humidity data is ensured; the Kevlar fiber is introduced to bundle with the sensing optical fiber, the bundled optical fiber can well avoid local excessive stretching; the spiral Kevlar is woven with the metal wire to improve the tensile strength of the spiral armor tube;

[0022] Highly adaptable and convenient for subsequent processing

[0023] The use of a stranded steel wire structure allows for direct stretching during cable formation, significantly enhancing the sensor's adaptability and stability in complex environments. The outer braided layer prevents the intelligent monofilaments from being squeezed out of the slots due to temperature and humidity variations, adapting to cable formation and hanging conditions.

[0024] Simple structure

[0025] The strand processing techniques, including bundling, armoring, and twisting, are all commonly used in traditional optical cable manufacturing, with mature production processes and low manufacturing costs. This simple structure and production process significantly reduces production costs and improves manufacturing efficiency, possessing the potential for large-scale application. This further enhances the practicality and economic viability of this invention in the field of bridge monitoring. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an embodiment of an ultra-weak fiber optic grating temperature and humidity sensing smart strand provided by this utility model.

[0027] Figure 2 This is a schematic diagram of a structural embodiment of a smart cable strand for a domestic suspension bridge provided by this utility model.

[0028] Figure 3 This is a structural schematic diagram of one embodiment of a domestic suspension bridge provided by this utility model.

[0029] In the above figures: 1. Reinforced concrete structure of the bridge; 2. Main cable of the bridge; 21. Smart strand of ultra-weak fiber grating multi-parameter sensing; 211. Humidity ultra-weak fiber grating array; 212. Temperature ultra-weak fiber grating array; 213. Kevlar fiber; 214. Spiral armor tube; 215. Spiral armor braided layer; 216. Outer stainless steel wire; 217. Central stainless steel wire; 218. Strand braided layer; 22. High-strength stainless steel wire. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments.

[0031] This embodiment provides a smart strand for sensing temperature and humidity in ultra-weak fiber Bragg gratings, such as... Figures 1-2 As shown, it 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 spiral armor braided layer 215, an outer stainless steel wire 216, a central stainless steel wire 217, and a strand braided layer 218.

[0032] The humidity ultra-weak fiber grating array 211, the temperature ultra-weak fiber grating array 212 and the Kevlar fiber 213 are combined and wrapped by the spiral armor tube 214, the spiral armor braid layer 215 is wrapped outside the spiral armor tube 214 to form a temperature and humidity intelligent monofilament, the temperature and humidity intelligent monofilament is twisted into a cable with five outer layer stainless steel wires 216 and a center stainless steel wire 217, and the outer braid layer 218 is braided; the center stainless steel wire 217 is located at the geometric center of the temperature and humidity intelligent monofilament and the five outer layer stainless steel wires 216.

[0033] In the above embodiment, the humidity ultra-weak fiber grating array 211 is made of a fine diameter ultra-weak fiber grating, which is coated with ordinary polyimide once and humidity sensitive polyimide material twice.

[0034] The coating thickness of the ordinary polyimide and the humidity sensitive polyimide material is 10 um.

[0035] In some embodiments, the temperature ultra-weak fiber grating array 212 is prepared by coating the ultra-weak fiber grating with an acrylic coating once.

[0036] In some preferred embodiments, the Kevlar fiber 213 is made of high-strength polyamide fiber with a diameter of 50 um, which is a continuous filament without breakage or entanglement during the bundling process.

[0037] In another preferred embodiment, the spiral armor braid layer 215 is made of stainless steel wire with a diameter of 0.2 mm, which is wrapped outside the spiral armor tube 214 to prevent the spiral armor tube from being stretched and overloaded. The diameter of the temperature and humidity intelligent monofilament should be consistent with the diameter of the outer layer stainless steel wire 216 and the center stainless steel wire 217.

[0038] In some embodiments, the braid layer 218 is made of stainless steel wire with a diameter of 0.2 mm, which prevents the temperature and humidity intelligent monofilament from falling off the other six stainless steel wires.

[0039] As another preferred embodiment of the utility model, the embodiment provides an application method of the ultra-weak fiber grating temperature and humidity sensing intelligent strand, which is characterized by comprising the following steps:

[0040] Step one, wrapping the humidity ultra-weak fiber grating array 211 and the temperature ultra-weak fiber grating array 212 with Kevlar fiber 213, and winding the spiral armor tube 214, then braiding the spiral armor braid layer 215 along the axial direction to form a temperature and humidity intelligent monofilament;

[0041] Step two, twist one center stainless steel wire 217 with the temperature and humidity intelligent monofilament and five outer layer stainless steel wires 216, and twist into a cable, and then weave a stockinette layer 218 along the length direction of the cable as a protective layer, to form the ultra-weak fiber grating temperature and humidity sensing intelligent stockinette 21.

[0042] Step three, bundle the ultra-weak fiber grating temperature and humidity sensing intelligent stockinette 21 as a center wire with other 90 high-strength stainless steel wires 22 to form a cable, and then hang the cable vertically through an anchoring platform, and use a zinc-magnesium alloy solution to cast an anchor head to form an intelligent cable.

[0043] Step four, hang the intelligent cable with two traction belts, so that the intelligent cable is hung on the traction cable without generating a large bending amplitude, thereby protecting the ultra-weak fiber grating temperature and humidity sensing intelligent stockinette during the hanging process, and entering the anchor to become a part of the main cable of the bridge.

[0044] Step five, use a cable gripper to install other ordinary cables in sequence through the traction cable, and the intelligent cable and the other ordinary cables together form the main cable of the bridge; when casting, the ultra-weak fiber grating temperature and humidity sensing intelligent stockinette is wrapped with a copper pipe to isolate the high temperature of casting and avoid the destruction of the ultra-weak fiber grating temperature and humidity sensing intelligent stockinette caused by high temperature during casting of the anchor head.

[0045] In the measurement process, when the external temperature changes, the ultra-weak fiber grating is affected by the thermal photoeffect and the thermal expansion of the acrylic coating, causing the center wavelength of the ultra-weak fiber grating to change, thereby realizing the measurement of the change of the external temperature; 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.

[0046] In the application of the utility model, the thickness of the humidity-sensitive polyimide material or the non-humidity-sensitive material coating layer can be adjusted to adjust the temperature and humidity measurement range and measurement accuracy of the sensor array.

[0047] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the utility model and are not limiting. Although the utility model has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the utility model can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions of the utility model, and all of them should be covered in the scope of the claims of the utility model.

Claims

1. An ultra-weak fiber grating temperature and humidity sensing intelligent strand, characterized in that, 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 tube (214), a spiral armor braid layer (215), an outer layer stainless steel wire (216), a center stainless steel wire (217), and a strand braid layer (218). The humidity ultra-weak fiber grating array (211) and the temperature ultra-weak fiber grating array (212) are combined with the Kevlar fiber (213), and then wrapped by the spiral armor tube (214), and the spiral armor braid layer (215) is wrapped outside the spiral armor tube (214) to form a temperature and humidity intelligent monofilament; the temperature and humidity intelligent monofilament is twisted with five outer layer stainless steel wires (216) and a center stainless steel wire (217) to form a cable, and a strand braid layer (218) is braided outside, and the center stainless steel wire (217) is located at the geometric center of the temperature and humidity intelligent monofilament and the five outer layer stainless steel wires (216). 2.The ultra-weak fiber grating temperature and humidity sensing smart strand according to claim 1, characterized in that, The Kevlar fiber (213) has a diameter of 50 um and is a continuous filament. 3.The ultra-weak fiber grating temperature and humidity sensing smart yarn of claim 1, wherein, The spiral armor braid layer (215) is braided by stainless steel wires with a diameter of 0.2 mm, and the spiral armor braid layer (215) is externally coated with the spiral armor tube (214). 4.The ultra-weak fiber grating temperature and humidity sensing smart yarn of claim 1, wherein, The strand braid layer (218) is braided by stainless steel wires with a diameter of 0.2 mm.

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