Bridge cable corrosion sensor

Abstract

The application discloses a bridge cable corrosion sensor, which comprises a main body, an expansion block, a sliding block, a fixing block, a fiber grating and a connecting rod. The main body comprises a bottom plate and at least one wall plate, and the wall plate is installed on the bottom plate. The expansion block is slidingly installed on the bottom plate, and the expansion block and the wall plate enclose a cavity for accommodating a corrosion test piece. The corrosion expansion of the corrosion test piece can drive the expansion block to slide on the bottom plate. The sliding block is slidingly installed on the bottom plate, the fixing block is installed on the bottom plate, and the fixing block is located in the movement direction of the sliding block. One end of the fiber grating is fixed on the fixing block, and the other end of the fiber grating is installed on the sliding block. One end of the connecting rod is hinged to the expansion block, and the other end of the connecting rod is hinged to the sliding block. The sliding of the expansion block drives the sliding block to move away from the fixing block through the connecting rod, and the fiber grating is strained under tension. The bridge cable corrosion sensor can fully utilize the rust expansion force, the measurement result is accurate, and the process of steel bar corrosion can be directly reflected.

Description

Technical Field

[0001] This invention relates to the field of cable corrosion technology, and more specifically to a bridge cable corrosion sensor. Background Technology

[0002] Cable-stayed bridges have become the preferred choice for long-span bridges due to their advantages such as large span, uniform internal force distribution, aesthetically pleasing design, and high load-bearing capacity. The cables, as the "lifeline" of a cable-stayed bridge, transfer the load from the main girder to the bridge towers while also restraining the deformation of the towers, playing a crucial role in the bridge's structural integrity. However, during operation, cable corrosion becomes an unavoidable problem. Although modern cables have multiple protective systems, over time, due to environmental corrosion and the coupled effects of long-term loads, cables will still slowly corrode, and may even suddenly break, leading to bridge damage. To prevent accidents, in recent years, cables have needed to be replaced due to corrosion, on average every fifteen to twenty years.

[0003] Given the above-mentioned cable corrosion, it is especially necessary to conduct health monitoring of the cables during their service life. If the working condition and health status of the structure cannot be monitored and accurately assessed, an accident will have an extremely negative impact on economic and social benefits.

[0004] Traditional methods for detecting steel wire corrosion mainly include: ultrasonic testing, magnetic leakage testing, radiation testing, magnetic expansion sensing, and visual inspection. Currently, visual inspection is the most widely used method in practical engineering. However, the equipment used in traditional methods is bulky and complex, and lacks real-time monitoring capabilities.

[0005] As an emerging sensing technology, fiber optic gratings (FBGs) are being integrated into cables to form intelligent systems that monitor internal corrosion in real time and determine the degree of corrosion, becoming a major direction for future cable corrosion assessment. Research on FBGs in corrosion monitoring is still in the experimental stage, mainly focusing on long-period gratings with external alloy coatings for corrosion sensors and pre-stressed fiber optic grating corrosion sensors. While these two methods offer high accuracy, they are difficult to directly reflect the corrosion process of the reinforcing steel because the primary corrosion target is not the steel itself. Summary of the Invention

[0006] Therefore, it is necessary to provide a bridge cable corrosion sensor to address the problems that existing steel wire corrosion detection methods lack real-time monitoring capabilities and are difficult to directly reflect the steel bar corrosion process.

[0007] A bridge cable corrosion sensor, comprising:

[0008] The main body includes a base plate and at least one wall panel, wherein the wall panel is mounted on the base plate;

[0009] An expansion block is slidably mounted on the base plate. The expansion block and the wall plate form a cavity for accommodating the corrosion test specimen. The corrosion expansion of the corrosion test specimen can drive the expansion block to slide on the base plate.

[0010] A slider is slidably mounted on the base plate;

[0011] A fixing block is mounted on the base plate, and the fixing block is located in the direction of movement of the slider;

[0012] A fiber optic grating, one end of which is fixed to the fixing block, and the other end of which is mounted on the slider; and

[0013] A connecting rod, one end of which is hinged to the expansion block, and the other end of which is hinged to the slider, slides the expansion block through the connecting rod, driving the slider to move away from the fixed block, and the fiber grating is subjected to tension and generates strain.

[0014] The aforementioned bridge cable corrosion sensor uses a fiber Bragg grating as the sensing element. This element is lightweight, has a small radius, stable chemical properties, and is unaffected by electromagnetic interference. Its high sensitivity and measurement accuracy are unmatched by traditional measuring equipment, enabling real-time monitoring. Furthermore, compared to direct-wound sensors, this type of sensor detects a wider range of corrosion, fully utilizes rust expansion force, and yields more accurate measurement results, directly reflecting the process of steel reinforcement corrosion.

[0015] In one embodiment, the wall panel is provided with a first groove, and the expansion block is provided with a second groove that matches the first groove, the first groove and the second groove forming the cavity.

[0016] In one embodiment, the wall panel is provided with multiple sets of corrosion holes, which are connected to the first groove.

[0017] In one embodiment, a guide block is further included, which is mounted on the base plate. The guide block has a guide hole, and the expansion block has a guide post, which is slidably inserted into the guide hole.

[0018] In one embodiment, an elastic element is provided within the guide hole, which provides an elastic force to keep the expansion block in contact with the corrosion test specimen.

[0019] In one embodiment, the base plate is provided with a guide rail, and the slider is slidably disposed on the guide rail.

[0020] In one embodiment, a slider cover plate is also included, which is installed on the slider. Both the slider cover plate and the fixing block are provided with receiving grooves for accommodating fiber Bragg gratings, and the fiber Bragg gratings are fixed in the receiving grooves with adhesive.

[0021] In one embodiment, the expansion block is provided with a connecting block, one end of the connecting rod is hinged to the connecting block, and the other end of the connecting rod is hinged to the slider cover plate.

[0022] In one embodiment, there are multiple wall panels arranged along the periphery of the base plate, with no wall panel forming a notch on one side of the base plate, and two wall panels located on the axis of the fiber grating respectively having an insertion hole and an exit hole.

[0023] In one embodiment, a main cover plate is also included, which covers the wall plate, and the main cover plate, the wall plate, and the base plate form an internal space for accommodating components. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0025] Figure 1 This is a schematic diagram of the structure of a bridge cable corrosion sensor in one embodiment;

[0026] Figure 2 for Figure 1 The diagram shows the bridge cable corrosion sensor after the main cover plate has been removed.

[0027] Figure 3 for Figure 2 The top view of the bridge cable corrosion sensor shown.

[0028] Figure 4 for Figure 2 A schematic diagram of the main structure;

[0029] Figure 5 for Figure 2 Schematic diagram of the structure of the expansion block;

[0030] Figure 6 This is a schematic diagram showing the stretching of the fiber grating as the connecting rod rotates.

[0031] Figure label:

[0032] 10-Main body, 12-Base plate, 14-Wall panel, 142-First groove, 144-Etching hole, 16-In-hole, 18-Out-hole, 20-Expansion block, 22-Second groove, 24-Guide post, 26-Connecting block, 30-Slider, 32-Guide rail, 34-Slider cover plate, 40-Fixing block, 42-Receiving groove, 50-Fiber grating, 60-Connecting rod, 70-Main body cover plate. Detailed Implementation

[0033] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0034] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0036] Please see Figure 1 and Figure 2 One embodiment of the bridge cable corrosion sensor includes a main body 10, an expansion block 20, a slider 30, a fixing block 40, a fiber optic grating 50, and a connecting rod 60.

[0037] Please refer to the following: Figure 3 The main body 10 is used to install other components of the bridge cable corrosion sensor. The main body 10 includes a base plate 12 and at least one wall plate 14, which is mounted on the base plate 12 and is used to cooperate with the expansion block 20. In one embodiment, there are multiple wall plates 14, which are arranged along the periphery of the base plate 12, and one side of the base plate 12 is not provided with a wall plate 14, forming a notch.

[0038] Specifically, the base plate 12 is rectangular in shape, and there are three wall panels 14. One of the long sides of the base plate 12 is not provided with a wall panel 14 to form an opening. Of course, in other embodiments, the shape of the base plate 12 and the number of wall panels 14 can be flexibly adjusted as needed.

[0039] The expansion block 20 is slidably mounted on the base plate 12. The expansion block 20 and the wall plate 14 form a cavity for accommodating the corrosion test specimen. The corrosion expansion of the corrosion test specimen can drive the expansion block 20 to slide on the base plate 12.

[0040] Please refer to the following: Figure 4 In one embodiment, the wall panel 14 is provided with a first groove 142, and the expansion block 20 is provided with a second groove 22 that matches the first groove 142. The first groove 142 and the second groove 22 form a cavity. Specifically, the first groove 142 is formed on the wall panel 14 along the long side of the base plate 12.

[0041] It is understood that in other embodiments, the cavity accommodating the corrosion test specimen may also be formed in other ways. For example, a groove may be formed on the wall panel 14, while the expansion block 20 may not have a groove, and the sidewall of the expansion block 20 may fit into the groove to form a cavity. Alternatively, the wall panel 14 may not have a groove, but a groove may be formed on the expansion block 20, and the sidewall of the main body 10 may fit into the groove to form a cavity.

[0042] Based on the above embodiments, the wall panel 14 is further provided with multiple sets of corrosion holes 144, which are connected to the first groove 142. External corrosive media enter the cavity through the corrosion holes 144, causing the corrosion test piece inside the cavity to corrode and expand, pushing the expansion block 20 to slide on the base plate 12. The multiple sets of corrosion holes 144 are evenly spaced along the extension direction of the first groove 142 to achieve uniform corrosion of the corrosion test piece.

[0043] In one embodiment, the corrosion test specimen is a high-strength galvanized steel wire. The diameter of the high-strength galvanized steel wire can be 5-7 mm. It is understood that the corrosion test specimen can be changed depending on the specific corrosion monitoring target.

[0044] Please see Figure 2 and Figure 5 In one embodiment, to ensure the stability of the expansion block 20's sliding motion, the bridge cable corrosion sensor further includes a guide block 28. The guide block 28 is mounted on the base plate 12 and has a guide hole. The expansion block 20 has a guide post 24, which is slidably inserted into the guide hole. The guide hole of the guide block 28, in conjunction with the guide post 24, can guide and limit the sliding motion of the expansion block 20, ensuring the stability of the expansion block 20's movement.

[0045] In one embodiment, to prevent the expansion block 20 from rotating due to uneven corrosion of the corrosion test piece, two guide posts 24 are provided, one at each end of the expansion block 20. Two guide blocks 28 are correspondingly provided, and the two guide posts 24 are inserted into the guide holes of the two guide blocks 28. Specifically, the guide post 24 is inserted 7mm into the guide hole, and a clearance fit of H6 / P5 is provided between the guide post 24 and the guide hole.

[0046] In one embodiment, an elastic element is provided within the guide hole. This elastic element provides elastic force to keep the expansion block 20 in contact with the corrosion test specimen, preventing any gap between the expansion block 20 and the corrosion test specimen, and ensuring that the corrosion expansion of the corrosion test specimen can act on the expansion block 20. Specifically, the elastic element can be a spring. Of course, the elastic element can also be other structures that can provide elastic force, such as a rubber column.

[0047] The slider 30 is slidably mounted on the base plate 12. In one embodiment, the base plate 12 is provided with a guide rail 32, and the slider 30 is slidably disposed on the guide rail 32, thereby achieving slidable mounting of the slider 30 on the base plate 12. The slider 30 contains stainless steel balls to ensure smooth sliding between the slider 30 and the guide rail 32, providing corrosion resistance while significantly reducing the impact of friction, thus improving accuracy. The slider 30 and the guide rail 32 are cast from S55C steel, which has good corrosion resistance and hardness.

[0048] It is understood that in other embodiments, the slider 30 can be slidably mounted on the base plate 12 in other ways, such as by providing a groove on the base plate 12 and sliding the slider 30 within the groove.

[0049] The fixing block 40 is mounted on the base plate 12, and the fixing block 40 is located in the movement direction of the slider 30 to avoid the sliding movement direction from making an angle with the axis of the fiber grating 50 after the fiber grating 50 is installed. In one embodiment, the fixing block 40 is fixed to the base plate 12 by bolts.

[0050] One end of the fiber Bragg grating 50 is fixed to the fixing block 40, and the other end of the fiber Bragg grating 50 is mounted on the slider 30. In one embodiment, the bridge cable corrosion sensor also includes a slider cover plate 34, which is mounted on the slider 30. Both the slider cover plate 34 and the fixing block 40 are provided with receiving grooves 42 for accommodating the fiber Bragg grating 50, and the fiber Bragg grating 50 is fixed in the receiving grooves 42 with adhesive.

[0051] In one embodiment, two sidewalls located on the axis of the fiber optic grating 50 are respectively provided with insertion holes 16 and exit holes 18, wherein the optical fiber and sheath can be inserted into the main body 10 through the insertion holes 16, and then the optical fiber and sheath can be exited outside the main body 10 through the exit holes 18. Specifically, the base plate 12 is rectangular, and the insertion holes 16 and exit holes 18 are respectively located on the two sidewalls 14 of the short side of the base plate 12.

[0052] One end of the connecting rod 60 is hinged to the expansion block 20, and the other end of the connecting rod 60 is hinged to the slider 30. The sliding of the expansion block 20 is transmitted to the slider 30 through the connecting rod 60 via its displacement, driving the slider 30 to move away from the fixed block 40. The fiber grating 50 is stretched and strained, resulting in wavelength shift. The degree of corrosion is determined by detecting the wavelength shift.

[0053] In one embodiment, the expansion block 20 is provided with a connecting block 26, one end of the connecting rod 60 is hinged to the connecting block 26, and the other end of the connecting rod 60 is hinged to the slider cover plate 34. Specifically, bearings are provided in the connecting rod 60 and the slider cover plate 34 and in the connecting rod 60 and the connecting block 26 for rotation. The inner ring of the bearing is tightly fitted, and the outer ring is clearance fitted.

[0054] Please refer to it again. Figure 1 In one embodiment, the bridge cable corrosion sensor also includes a main cover plate 70, which covers the wall plate 14. The main cover plate 70, the wall plate 14, and the base plate 12 form an internal space for accommodating components. The expansion block 20, the slider 30, the fixing block 40, the fiber optic grating 50, and the connecting rod 60 are housed in the internal space. The fiber optic grating 50 does not come into contact with the external environment, has a high survival rate in practical applications, and can ensure long-term real-time monitoring.

[0055] In one embodiment, apart from the slider 30 and the guide rail 32, the other components of the bridge cable corrosion sensor are made of 6061 aluminum alloy, which is not affected by the corrosion of high-strength steel wire and has a lower cost, thus improving the durability of the sensor.

[0056] The working principle of the aforementioned bridge cable corrosion sensor is as follows:

[0057] Push the expansion block 20 to open the cavity, and then place the corrosion test piece into the cavity. Release the expansion block 20, and the expansion block 20 will return to its original position under the action of the elastic element in the guide block 28, maintaining contact with the corrosion test piece.

[0058] Then, the two ends of the fiber optic grating 50 are respectively installed in the receiving groove 42 of the slider cover plate 34 and the fixing block 40, and then glue is applied to fix the fiber optic grating 50. Finally, the main body cover plate 70 is placed on the wall panel 14 and fixed by bolts to achieve the closure of the space inside the main body 10.

[0059] The corrosive medium is injected into the cavity through the corrosion hole 144, causing the corrosion test piece in the cavity to corrode and generate an expansion effect. This pushes the expansion block 20 away from the wall plate 14 and slides it away. The connecting rod 60 transmits its displacement to the slider 30, causing the slider 30 to move away from the fixed block 40. As a result, the fiber optic grating 50 is stretched and strained, resulting in wavelength shift. The degree of corrosion is determined by detecting the wavelength shift.

[0060] Please see Figure 6 In this diagram, let point A be the hinge point between connecting rod 60 and expansion block 20, point C be the hinge point between connecting rod 60 and slider 30, point C also be the connection point between fiber optic grating 50 and slider 30, and point D be the connection point between connecting rod 60 and fixed block 40. Point A is perpendicular to point O from fiber optic grating 50, and the angle between connecting rod 60 and line OA is θ. After connecting rod 60 rotates, point A moves to A', and point C moves to C'.

[0061] The relationship between the physical quantity monitored by the fiber optic grating 50 sensor designed in this invention and the grating wavelength satisfies the following expression:

[0062]

[0063] In the formula, k T Δλ is the sensor sensitivity coefficient; Δλ is the change in grating wavelength; ΔD is the change in wire diameter; L1 is the length of the connecting rod 60; L is the length of the fiber optic grating 50.

[0064] The aforementioned bridge cable corrosion sensor uses a fiber Bragg grating 50 as its sensing element. This element is lightweight, has a small radius, stable chemical properties, and is unaffected by electromagnetic interference. Its high sensitivity and measurement accuracy are unmatched by traditional measuring equipment. Secondly, compared to direct-wound types, this type of sensor detects a wider range of corrosion, fully utilizes rust expansion force, and yields more accurate measurements, directly reflecting the steel reinforcement corrosion process. Finally, the fiber Bragg grating 50 is placed inside the sensor, not in contact with the external environment, resulting in a high survival rate in practical applications and ensuring long-term real-time monitoring.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A bridge cable corrosion sensor, characterized in that, include: The main body includes a base plate and at least one wall panel, wherein the wall panel is mounted on the base plate; An expansion block is slidably mounted on the base plate. The expansion block and the wall plate form a cavity for accommodating the corrosion test specimen. The corrosion expansion of the corrosion test specimen can drive the expansion block to slide on the base plate. A slider is slidably mounted on the base plate; A fixing block is mounted on the base plate, and the fixing block is located in the direction of movement of the slider; A fiber optic grating, one end of which is fixed to the fixing block, and the other end of which is mounted on the slider; and A connecting rod, one end of which is hinged to the expansion block and the other end of which is hinged to the slider, slides the expansion block through the connecting rod, driving the slider to move away from the fixed block, and the fiber grating is stretched and generates strain; It also includes a guide block, which is mounted on the base plate. The guide block has a guide hole, and the expansion block has a guide post, which is slidably inserted into the guide hole.

2. The bridge cable corrosion sensor according to claim 1, characterized in that, The wall panel is provided with a first groove, and the expansion block is provided with a second groove that matches the first groove. The first groove and the second groove together form the cavity.

3. The bridge cable corrosion sensor according to claim 2, characterized in that, The wall panel is provided with multiple sets of corrosion holes, and the multiple sets of corrosion holes are connected to the first groove.

4. The bridge cable corrosion sensor according to claim 1, characterized in that, An elastic element is provided inside the guide hole, which provides elastic force to keep the expansion block in contact with the corrosion test piece.

5. The bridge cable corrosion sensor according to claim 1, characterized in that, The base plate is provided with a guide rail, and the slider is slidably mounted on the guide rail.

6. The bridge cable corrosion sensor according to claim 1, characterized in that, It also includes a slider cover plate, which is installed on the slider. Both the slider cover plate and the fixing block are provided with receiving grooves for accommodating fiber Bragg gratings. The fiber Bragg gratings are fixed in the receiving grooves with adhesive.

7. The bridge cable corrosion sensor according to claim 6, characterized in that, The expansion block is provided with a connecting block, one end of the connecting rod is hinged to the connecting block, and the other end of the connecting rod is hinged to the slider cover plate.

8. The bridge cable corrosion sensor according to claim 1, characterized in that, The number of wall panels is multiple, and the multiple wall panels are arranged along the periphery of the base plate. One side of the base plate is not provided with a wall panel to form a notch. Two wall panels located on the axis of the fiber grating are respectively provided with an insertion hole and an exit hole.

9. The bridge cable corrosion sensor according to claim 1, characterized in that, It also includes a main cover plate, which covers the wall plate, and the main cover plate, the wall plate and the bottom plate form an internal space for accommodating the components.

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