Intelligent steel strand with strain temperature and humidity multi-parameter sensing function and manufacturing method thereof

Abstract

The invention provides an intelligent steel strand with a strain temperature and humidity multi-parameter sensing function and a manufacturing method of the intelligent steel strand. The intelligent steel strand comprises a central wire with a strain temperature and humidity multi-parameter sensing function and side wires which are formed by common steel wires and are wound around the central wire. According to the intelligent steel strand, under the condition that the original structure is not changed, a hole is formed in the center wire to integrate strain, temperature and humidity optical fiber sensors, and the subsequent manufacturing and processing technology of the steel strand is not affected. According to the intelligent steel strand, the three parameters of stress, temperature and humidity are obtained at the same time, the environment and the stress state of the steel strand can be comprehensively known, and more accurate structure health condition evaluation is provided. In addition, the central wire is divided into a sensing section and a pressure-bearing section which respectively adopt hollow steel tube structures with different thicknesses, so that the arrangement and working performance of the optical fiber and the sensor and the survival rate of the optical fiber at the anchoring position are ensured. The intelligent steel strand has the advantages of being high in survival rate, good in durability, multiple in monitoring parameters, high in precision, not prone to interference and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of structural health monitoring and prestressed engineering structures, and in particular to an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions and a manufacturing method thereof. Background Art

[0002] Steel strand is a kind of steel wire rope made of multiple strands of high-strength steel wires. It is widely used in construction, bridges, prestressed concrete and other fields because of its advantages such as high strength, corrosion resistance, good toughness, ductility and stability. However, traditional steel strands are affected by the working environment and will suffer from fatigue and corrosion during service. If they are not discovered and handled in time, they will threaten the safety of the structure during service. At present, the optical fiber sensor integrated in the intelligent steel strand can only monitor the strain, but it has the disadvantages of low accuracy, large interference and poor stability. In addition, it is difficult to lay temperature and humidity sensors due to the internal space limitation of the steel strand. Temperature data is crucial for temperature compensation of strain data, and humidity is a key factor affecting the corrosion damage of steel strand. Therefore, the development of an intelligent steel strand with the ability to synchronously monitor multiple parameters of strain, temperature and humidity is of great significance for accurately grasping the service performance of the steel strand. Summary of the invention

[0003] The present invention proposes an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions and a manufacturing method thereof, so as to solve the problems of low monitoring accuracy, susceptibility to interference, poor stability and inability to simultaneously monitor strain, temperature and humidity in existing intelligent steel strands.

[0004] The present invention is realized by the following technical scheme. The present invention proposes an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions, the intelligent steel strand comprising: a central wire 1 with strain, temperature and humidity multi-parameter sensing functions and 6 side wires 2 composed of steel wires and wound around the central wire 1;

[0005] The central wire 1 is composed of a sensing section 3 in the middle and pressure-bearing sections 4 at both ends: the sensing section 3 is a hollow steel tube 5 with a relatively thin wall thickness, a sensing optical fiber 6 is arranged in the hollow steel tube 5 with a relatively thin wall thickness, and one or more groups of strain measurement gratings 7, temperature measurement gratings 8 and humidity measurement gratings 9 are arranged in series on the sensing optical fiber 6; the pressure-bearing section 4 is arranged in the clamping anchoring area at both ends of the intelligent steel strand, and a hollow steel tube 10 with a relatively thick wall thickness is used to resist the pressure applied to the intelligent steel strand by the clamping in the anchoring area, so as to avoid damage to the sensing optical fiber 6.

[0006] Furthermore, the outer diameter of the hollow steel pipe 10 of the pressure section 4 is the same as the outer diameter of the hollow steel pipe 5 of the sensing section 3 .

[0007] Furthermore, within a distance where the hollow steel pipe 10 of the pressure section 4 is connected to the hollow steel pipe 5 of the sensing section 3, the outer side of the hollow steel pipe 10 of the pressure section 4 is partially cut so that the outer diameter of the cut portion of the hollow steel pipe 10 of the pressure section 4 is slightly smaller than the inner diameter of the hollow steel pipe 5 of the sensing section 3; the hollow steel pipe 10 of the pressure section 4 is inserted into the hollow steel pipe 5 of the sensing section 3, and the two are connected by welding.

[0008] Furthermore, a hole is punched on the surface of the hollow steel tube 5 of the sensing section 3 near the strain measurement grating 7 , and an adhesive is injected to bond and fix the strain measurement grating 7 to the inner wall of the hollow steel tube 5 of the sensing section 3 .

[0009] Furthermore, a stress-isolating steel casing 11 is provided at the temperature measuring grating 8 for stress isolation.

[0010] Furthermore, the surface of the humidity measuring grating 9 is coated with a humidity sensitive material, and a stress isolating steel casing 12 with ventilation holes is provided for stress isolation. Ventilation holes are provided on the surface of the hollow steel pipe 5 of the sensing section 3 near the humidity measuring grating 9 .

[0011] Furthermore, after the multiple strain measurement gratings 7, temperature measurement gratings 8 and humidity measurement gratings 9 in the sensing section 3 are connected in series with the sensing optical fiber 6, both ends of the sensing optical fiber 6 are led out from the hollow steel pipe 10 of the pressure section 4 and connected to the fiber grating demodulator for measurement.

[0012] The present invention also proposes a method for manufacturing an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions, the method steps comprising:

[0013] Step 1: Determine the strain, temperature and humidity measurement positions of the intelligent steel strand, connect the strain measurement grating 7, the temperature measurement grating 8 with a stress isolation sleeve, and the humidity measurement grating 9 with a stress isolation sleeve with a vent hole with a sensing optical fiber 6 of corresponding length to form a sensing grating string;

[0014] Step 2: Open holes on the surface of the hollow steel tube 5 at the positions of the strain measurement grating 7 and the humidity measurement grating 9 in the sensing section 3;

[0015] Step 3: insert the sensing grating string into the hollow steel tube 5 of the sensing section 3, and inject an adhesive into the opening of the strain measurement grating 7 to fix the strain measurement grating 7;

[0016] Step 4: The two ends of the sensing grating string pass through the hollow steel tube 10 of the pressure section 4 respectively; the cut ends of the hollow steel tube 10 of the pressure section 4 are inserted into the two ends of the hollow steel tube 5 of the sensing section 3, and then the two are connected by welding; finally, a central wire 1 with strain, temperature and humidity multi-parameter sensing functions is formed;

[0017] Step 5: Use the central wire 1 with strain, temperature and humidity multi-parameter sensing functions as the central wire of the intelligent steel strand, use 6 steel wires as the side wires 2 of the intelligent steel strand to wrap around the central wire 1, and twist them into intelligent steel strands with strain, temperature and humidity multi-parameter sensing functions through a machine.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions in the present application integrates strain, temperature and humidity optical fiber sensors by opening a hole inside the central wire without changing the original structure, which does not affect the subsequent manufacturing and processing technology of the steel strand; the central wire is divided into a sensing section and a pressure-bearing section, respectively adopting hollow steel pipe structures of different thicknesses, thereby ensuring the layout and working performance of the optical fiber and sensor and the survival rate of the optical fiber at the anchoring point; the temperature and humidity sensors adopt a stress-isolating steel casing structure to effectively isolate the influence of external stress on the measurement results, thereby ensuring the reliability of the monitoring results; the intelligent steel strand simultaneously obtains the three parameters of stress, temperature and humidity, which can fully understand the environment and stress state of the steel strand, provide more accurate structural health assessment, avoid the interaction between different environmental factors, and improve the accuracy of monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 It is a three-dimensional diagram of the intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions of the present invention;

[0022] Figure 2 This is a cross-sectional view of the intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions of the present invention;

[0023] Figure 3 It is a structural schematic diagram of the central wire sensing section of the intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions of the present invention;

[0024] Figure 4 It is a schematic diagram of the structure of the intelligent steel strand anchoring end with strain, temperature and humidity multi-parameter sensing functions of the present invention;

[0025] Markings in the figure: 1-center wire, 2-side wire, 3-sensing section, 4-pressure-bearing section, 5-sensing section hollow steel pipe, 6-sensing optical fiber, 7-strain measurement grating, 8-temperature measurement grating, 9-humidity measurement grating, 10-pressure-bearing section hollow steel pipe, 11-stress isolation steel casing, 12-stress isolation steel casing with vents. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Combination Figure 1-Figure 4 The present invention proposes an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions, the intelligent steel strand comprising: a central wire 1 with strain, temperature and humidity multi-parameter sensing functions and 6 side wires 2 composed of steel wires and wound around the central wire 1;

[0028] The central wire 1 is composed of a sensing section 3 in the middle and pressure-bearing sections 4 at both ends: the sensing section 3 is a hollow steel tube 5 with a relatively thin wall thickness, a sensing optical fiber 6 is arranged in the hollow steel tube 5 with a relatively thin wall thickness, and one or more groups of strain measurement gratings 7, temperature measurement gratings 8 and humidity measurement gratings 9 are arranged in series on the sensing optical fiber 6; the pressure-bearing section 4 is arranged in the clamping anchoring area at both ends of the intelligent steel strand, and a hollow steel tube 10 with a relatively thick wall thickness is used to resist the pressure applied to the intelligent steel strand by the clamping in the anchoring area, so as to avoid damage to the sensing optical fiber 6.

[0029] The outer diameter of the hollow steel tube 10 of the pressure section 4 is the same as the outer diameter of the hollow steel tube 5 of the sensing section 3. Within a distance where the hollow steel tube 10 of the pressure section 4 is connected to the hollow steel tube 5 of the sensing section 3, the outer side of the hollow steel tube 10 of the pressure section 4 is partially cut so that the outer diameter of the cut portion of the hollow steel tube 10 of the pressure section 4 is slightly smaller than the inner diameter of the hollow steel tube 5 of the sensing section 3; the hollow steel tube 10 of the pressure section 4 is inserted into the hollow steel tube 5 of the sensing section 3, and the two are connected by welding.

[0030] A hole is punched on the surface of the hollow steel tube 5 of the sensing section 3 near the strain measurement grating 7 , and an adhesive is injected to bond and fix the strain measurement grating 7 to the inner wall of the hollow steel tube 5 of the sensing section 3 .

[0031] A stress-isolating steel casing 11 is provided at the temperature measuring grating 8 for stress isolation.

[0032] The surface of the humidity measuring grating 9 is coated with a humidity sensitive material, and a stress isolating steel casing 12 with ventilation holes is provided for stress isolation. Ventilation holes are provided on the surface of the hollow steel pipe 5 of the sensing section 3 near the humidity measuring grating 9 .

[0033] After the multiple strain measurement gratings 7, temperature measurement gratings 8 and humidity measurement gratings 9 in the sensing section 3 are connected in series with the sensing optical fiber 6, both ends of the sensing optical fiber 6 are led out from the hollow steel pipe 10 of the pressure section 4 and connected to the fiber grating demodulator for measurement.

[0034] The present invention proposes an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions. The intelligent steel strand includes a central wire with strain, temperature and humidity multi-parameter sensing functions and side wires composed of ordinary steel wires and wound around the central wire. The intelligent steel strand integrates strain, temperature and humidity optical fiber sensors by opening holes inside the central wire without changing the original structure, and does not affect the subsequent manufacturing and processing technology of the steel strand. The intelligent steel strand simultaneously obtains three parameters of stress, temperature and humidity, which can fully understand the environment and stress state of the steel strand and provide a more accurate assessment of the structural health status. In addition, the central wire is divided into a sensing section and a pressure-bearing section, and hollow steel pipe structures of different thicknesses are respectively used to ensure the layout and working performance of the optical fiber and sensor and the survival rate of the optical fiber at the anchoring point. The intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions in the present invention has the advantages of high survival rate, good durability, multiple monitoring parameters, high precision and low susceptibility to interference.

[0035] The present invention also proposes a method for manufacturing an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions, the method steps comprising:

[0036] Step 1: Determine the strain, temperature and humidity measurement positions of the intelligent steel strand, connect the strain measurement grating 7, the temperature measurement grating 8 with a stress isolation sleeve, and the humidity measurement grating 9 with a stress isolation sleeve with a vent hole with a sensing optical fiber 6 of corresponding length to form a sensing grating string;

[0037] Step 2: Open holes on the surface of the hollow steel tube 5 at the positions of the strain measurement grating 7 and the humidity measurement grating 9 in the sensing section 3;

[0038] Step 3: insert the sensing grating string into the hollow steel tube 5 of the sensing section 3, and inject an adhesive into the opening of the strain measurement grating 7 to fix the strain measurement grating 7;

[0039] Step 4: The two ends of the sensing grating string pass through the hollow steel tube 10 of the pressure section 4 respectively; the cut ends of the hollow steel tube 10 of the pressure section 4 are inserted into the two ends of the hollow steel tube 5 of the sensing section 3, and then the two are connected by welding; finally, a central wire 1 with strain, temperature and humidity multi-parameter sensing functions is formed;

[0040] Step 5: Use the central wire 1 with strain, temperature and humidity multi-parameter sensing functions as the central wire of the intelligent steel strand, use 6 steel wires as the side wires 2 of the intelligent steel strand to wrap around the central wire 1, and twist them into intelligent steel strands with strain, temperature and humidity multi-parameter sensing functions through a machine.

[0041] The present invention relates to an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions. Steel strand is a steel wire rope formed by twisting multiple strands of high-strength steel wires. It is widely used in buildings, bridges, prestressed concrete and other fields because of its advantages such as high strength, corrosion resistance, good toughness, ductility and stability. However, traditional steel strands are affected by the working environment and will experience fatigue and corrosion during service. If they are not discovered and handled in time, they will threaten the safety of the structure during service. The current intelligent steel strand integrated optical fiber sensor can only monitor the strain of the steel strand, but it also has the disadvantages of low accuracy, large interference influence and poor stability. In addition, it is difficult to lay temperature and humidity sensors due to the internal space limitation of the steel strand. Temperature data is crucial for temperature compensation of strain data, and humidity is a key factor affecting corrosion damage of steel strands. To this end, the present invention proposes an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions. Without changing the original structure, the steel strand has a hole opened inside the central wire to integrate strain, temperature and humidity fiber optic sensors, which does not affect the subsequent manufacturing and processing technology of the steel strand; the central wire is divided into a sensing section and a pressure-bearing section, each of which adopts a hollow steel pipe structure of different thicknesses to ensure the layout and working performance of the optical fiber and sensors and the survival rate of the optical fiber at the anchor point; the temperature and humidity sensors adopt a stress-isolating steel casing structure to effectively isolate the influence of external stress on the measurement results, thereby ensuring the reliability of the monitoring results; in addition, the intelligent steel strand can simultaneously obtain three parameters of stress, temperature and humidity, which can fully understand the environment and stress state of the steel strand and provide a more accurate assessment of the structural health status.

[0042] The above is a detailed introduction to the intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions and its manufacturing method proposed in the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. An intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions, characterized in that: The intelligent steel strand comprises: a central wire (1) having a strain, temperature and humidity multi-parameter sensing function and six side wires (2) consisting of steel wires and wound around the central wire (1); The central wire (1) is composed of a sensing section (3) in the middle and pressure-bearing sections (4) at both ends. The sensing section (3) is a hollow steel tube (5) with a relatively thin wall thickness. A sensing optical fiber (6) is arranged in the hollow steel tube (5) with a relatively thin wall thickness. One or more sets of strain measurement gratings (7), temperature measurement gratings (8) and humidity measurement gratings (9) are arranged in series on the sensing optical fiber (6). The pressure-bearing section (4) is arranged in the clamping plate anchoring area at both ends of the intelligent steel strand. A hollow steel tube (10) with a relatively thick wall thickness is used to resist the pressure applied to the intelligent steel strand by the clamping plate in the anchoring area, thereby avoiding damage to the sensing optical fiber (6).

2. The intelligent steel strand according to claim 1, characterized in that: The outer diameter of the hollow steel pipe (10) of the pressure-bearing section (4) is the same as the outer diameter of the hollow steel pipe (5) of the sensing section (3).

3. The intelligent steel strand according to claim 2, characterized in that: Within a distance where the hollow steel pipe (10) of the pressure-bearing section (4) is connected to the hollow steel pipe (5) of the sensing section (3), the outer side of the hollow steel pipe (10) of the pressure-bearing section (4) is partially cut so that the outer diameter of the cut portion of the hollow steel pipe (10) of the pressure-bearing section (4) is slightly smaller than the inner diameter of the hollow steel pipe (5) of the sensing section (3); the hollow steel pipe (10) of the pressure-bearing section (4) is inserted into the hollow steel pipe (5) of the sensing section (3), and the two are connected by welding.

4. The intelligent steel strand according to claim 3, characterized in that: The hollow steel tube (5) of the sensing section (3) is perforated on the surface near the strain measurement grating (7), and an adhesive is injected to bond and fix the strain measurement grating (7) to the inner wall of the hollow steel tube (5) of the sensing section (3).

5. The intelligent steel strand according to claim 4, characterized in that: A stress-isolating steel casing (11) is arranged at the temperature measuring grating (8) to perform stress isolation.

6. The intelligent steel strand according to claim 5, characterized in that: The surface of the humidity measuring grating (9) is coated with a humidity sensitive material, and a stress isolating steel casing (12) with ventilation holes is provided for stress isolation. Ventilation holes are provided on the surface of the hollow steel pipe (5) of the sensing section (3) near the humidity measuring grating (9).

7. The intelligent steel strand according to claim 6, characterized in that: After the multiple strain measurement gratings (7), temperature measurement gratings (8) and humidity measurement gratings (9) in the sensing section (3) are connected in series with a sensing optical fiber (6), both ends of the sensing optical fiber (6) are led out from the hollow steel pipe (10) of the pressure section (4) and connected to a fiber grating demodulator for measurement.

8. A method for manufacturing an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions according to any one of claims 1 to 7, the method steps comprising: Step 1: Determine the strain, temperature and humidity measurement positions of the intelligent steel strand, connect the strain measurement grating (7), the temperature measurement grating with a stress isolation sleeve (8) and the humidity measurement grating with a vent stress isolation sleeve (9) with corresponding lengths of sensing optical fiber (6) to form a sensing grating string; Step 2: opening holes on the surface of the hollow steel tube (5) at the positions of the strain measurement grating (7) and the humidity measurement grating (9) of the sensing section (3); Step 3: insert the sensing grating string into the hollow steel tube (5) of the sensing section (3), and inject an adhesive into the opening of the strain measurement grating (7) to fix the strain measurement grating (7); Step 4: The two ends of the sensing grating string are respectively passed through the hollow steel tube (10) of the pressure-bearing section (4); the cut ends of the hollow steel tube (10) of the pressure-bearing section (4) are inserted into the two ends of the hollow steel tube (5) of the sensing section (3), and then the two are connected by welding; finally, a central wire (1) with strain, temperature and humidity multi-parameter sensing functions is formed; Step 5: Use a central wire (1) with strain, temperature and humidity multi-parameter sensing functions as the central wire of the intelligent steel strand, use 6 steel wires as the side wires (2) of the intelligent steel strand to wrap around the central wire (1), and twist them into an intelligent steel strand with strain, temperature and humidity multi-parameter sensing functions through a machine.

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