WO2024067233A1 - Bulge self-sensing plate type support, manufacturing method, monitoring system and monitoring method - Google Patents

Abstract

A monitoring method for a monitoring system of a bulge self-sensing plate type support. The plate type support is based on a circular plate type support (1), spirally wound strain sensing optical fibers (2) are arranged and fixed on the annular side face of the circular plate type support (1). The monitoring system is based on the plate type support, and by means of a transmission optical fiber (3), the strain sensing optical fibers (2) of a plurality of plate type supports (1) and an optical fiber signal analysis device (4) are connected in series to form a circuit. The monitoring method comprises: B1, measuring an optical power loss value; B2, calculating a bulging strain value of a circular plate type support (1); B3, repeatedly calculating to obtain all bulging strain values; and B4, determining the health condition of the support according to the change in the bulging strain value.

Description

Plate support with self-sensing bulge, manufacturing method, monitoring system and monitoring method

This application claims priority to Chinese patent application 202211170369.8 filed on September 26, 2022.

Technical Field

The present invention relates to the technical field of bridge bearing mechanical response monitoring, and in particular to a bulge self-sensing plate-type bearing and a manufacturing method, a monitoring system and a monitoring method.

Background technique

Bridge bearings are important components of bridge structures. They connect the upper and lower structures of bridges. Their main function is to transfer the upper load of the bridge structure to the lower structure. They can coordinate the deformation of the upper structure and play an important role in ensuring the normal operation of the bridge. Therefore, the health of the bearings is related to the safe operation of the entire bridge structure. There are many types of defects and diseases in bridge bearings. The uneven bulging of plate rubber bearings is a typical defect. When the plate rubber and the reinforcing steel plate in the bearing are poorly bonded, the steel plate and rubber will debond under the load, causing uneven bulging. In severe cases, bulging, cracking, and even bursting will occur.

Bridge bearing monitoring is often a relatively weak link in bridge health monitoring. The loss or damage of bearings is difficult to detect and correct in time, which may cause the main structure of the bridge to tilt at the least or fall off at the worst. Previous monitoring methods mainly relied on manual inspection. Point sensors represented by strain gauges and displacement gauges are often difficult to function due to the size and durability of the sensors themselves. With the development of drones and photography technology, monitoring methods based on automatic inspections and fixed-point video technology have begun to emerge. Constrained by the location of the bridge and the limited space of the bearings, manual inspection methods cannot detect the stress conditions of the bearings and cannot determine the actual working status of the bearings. Point monitoring methods are limited by the climate and environment of the bridge and are difficult to ensure quality. New monitoring methods cannot take into account costs, and the above monitoring technologies are difficult to achieve wide-area coverage and ultra-high-definition coverage. Long-term real-time monitoring makes it difficult to reconcile the contradiction between cost and massive, continuous measurements, and thus it is impossible to monitor the health status of bridge bearings in real time.

With the continuous expansion of the number of bridges in my country, the number of bearings equipped is in the hundreds of millions. The detection workload of bridge bearings is complicated, and intelligent bearing monitoring methods and systems with high automation and large coverage are still in the exploratory stage. In response to the above problems, focusing on the key issue of uneven bulging defect disease detection of plate-type rubber bearings, a real-time intelligent perception method for plate-type bearings and uneven bulging defect diseases is designed for long-term, durable and automated use.

Summary of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies of manual inspection in the prior art, to provide a plate bearing with self-sensing bulging and a manufacturing method, a monitoring system and a monitoring method, which solve the problems that rectangular plate rubber bearings rely on manual regular inspections, have high manpower and material costs, limited inspection frequency, and cannot fully and timely detect the defects of bridge components such as bearings. Reasonable layout methods and layout parameters are determined to facilitate the interpretation and analysis of detection parameters, and can simultaneously perform online self-sensing monitoring of uneven bulging defects of massive bearings, can continuously monitor with high precision, high durability, long distance and long duration, and carry out targeted on-site inspections and maintenance. It has the advantages of wide coverage and low cost, and has good engineering application value.

In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

The bulge self-sensing plate support includes a circular plate support and a strain sensing optical fiber. The strain sensing optical fiber is spirally wound around the side of the circular plate support with the vertical center axis of the circular plate support as the center. The strain sensing optical fiber is wound around the side of the circular plate support for multiple turns and fixed. The strain sensing optical fiber has a head end and a tail end for external connection. The existing bridge support inspection is carried out by regular on-site inspections. This method has limited inspection frequency, high manpower and material costs, low efficiency, and cannot detect abnormalities of bridge supports in a timely manner. This solution uses a circular plate support, and the strain sensing optical fiber can be smoothly wound into a spiral. status to avoid breakage. At the same time, the winding setting of the strain sensing optical fiber can simplify the calculation. The bulging condition of the circular plate support can be monitored through the optical power loss value and the curvature radius change value of the strain sensing optical fiber. The deformation can be monitored in real time to understand the actual bulging condition of the circular plate support and carry out targeted on-site inspection and maintenance.

In a preferred embodiment of the present invention, the strain sensing optical fiber is a single-mode optical fiber, and the outer diameter of the strain sensing optical fiber is ≤1 mm. By setting the single-mode optical fiber, it is convenient to set it on the side of the circular plate support, which can improve the optical fiber sensing accuracy.

In a preferred embodiment of the present invention, the winding number n of the strain sensing optical fiber is in the range of [10, 15]; by setting the winding number, a sufficient number of optical fiber windings is ensured, which helps to demodulate the optical fiber sensing signal while avoiding excessive increase in the sensing gauge length and reducing the sensing performance.

In a preferred embodiment of the present invention, the side of the circular plate support is provided with a spiral groove around itself, and the groove is used to embed the strain sensing optical fiber; through the setting of the groove shape, it is convenient to spirally wind the strain sensing optical fiber to form a spiral shape.

In a preferred embodiment of the present invention, the depth of the groove is 1.5-2.5 mm. The groove is provided to ensure that the strain sensing optical fiber can be embedded in the side of the circular plate support, so that it is convenient to wind it on the circular plate support.

In a preferred embodiment of the present invention, the above-mentioned plate support also includes packaging glue, and the strain sensing optical fiber and the circular plate support are fixed by the packaging glue; through the setting of the packaging glue, the strain sensing optical fiber can be fixed, and at the same time, protection is formed on the outside of the strain sensing optical fiber to avoid damage caused by external loads acting on the optical fiber, thereby ensuring that the accuracy of the test is not affected.

The monitoring system of the plate-type support with bulge self-sensing adopts the plate-type support with bulge self-sensing. The monitoring system includes a circular plate support, a strain sensing optical fiber, a transmission optical fiber and an optical fiber signal analysis device. The head ends and tail ends of the strain sensing optical fibers of multiple circular plate supports are respectively connected to the transmission optical fibers. The optical fiber signal analysis device and the multiple strain sensing optical fibers are connected in series through the transmission optical fiber to form a loop. Through the transmission optical fiber, multiple circular plate supports can be connected in series and connected to the optical fiber signal analysis device. The real-time optical power loss value of the strain sensing optical fiber is measured by the optical fiber signal analysis device, which can provide data support for analyzing the bulging condition of the circular plate support, can perform real-time monitoring remotely, and realize online analysis of a large number of circular plate supports.

In a preferred embodiment of the present invention, the transmission optical fiber is armored optical fiber; the armored optical fiber can protect the portion between different circular plate supports, thereby preventing the optical fiber from being affected by external loads and ensuring the transmission of optical fiber signals.

A method for manufacturing a plate-type support with self-sensing bulge, and manufacturing the plate-type support with self-sensing bulge, the manufacturing method comprises the following steps:

A1. A spiral groove is arranged on the annular side of the circular plate support, which is wound around the circular plate support for multiple turns, and the groove is cleaned with a cleaning liquid;

A2. Lay the strain sensing optical fiber tightly in the groove. During the laying, the strain sensing optical fiber is stretched and laid by applying prestress, and the strain sensing optical fiber is tested to ensure that the strain sensing optical fiber is intact.

A3. Reserve a section of strain sensing optical fiber outside the two ends of the groove, and use them as the head and tail ends of the strain sensing optical fiber respectively. Inject packaging glue into the groove to seal the groove. Finally, apply a layer of packaging glue with a thickness of 0.5 to 1.5 mm on the side of the strain sensing optical fiber.

By first setting a groove on the side of the circular plate support, laying the strain sensing optical fiber, and finally encapsulating it with glue, the strain sensing optical fiber can be combined on the basis of the circular plate support to form an overall circular plate support as a module, which is convenient for connection when networking as a monitoring system, and the networking connection is convenient and fast. Quick.

The monitoring method of the plate bearing monitoring system with bulge self-sensing adopts the above-mentioned plate bearing monitoring system with bulge self-sensing, and the circular plate bearing is pre-set during the bridge construction. The monitoring method includes the following steps:

B1. Measure the initial optical power loss value, actual optical power loss value and curvature radius change value of a single-turn strain sensing optical fiber through an optical fiber signal analysis device;

B2. Calculate the bulging strain value ε _i of the strain sensing optical fiber at the side of the circular plate support through the change value of the curvature radius of a single circle and the difference in optical power loss:

ΔR _i ＝ε _i R _i

Wherein, ΔB _i is the optical power loss difference of a single-turn strain sensing optical fiber caused by the bulging of the outer side of the circular plate support, Δα _i is the macro bending loss coefficient of the strain sensing optical fiber, that is, the bending optical power loss difference of the unit length of the strain sensing optical fiber, r is the radius of the circular plate support, ε _i is the bulging strain value of the outer side of the circular plate support at the position of the single-turn wound strain sensing optical fiber, d is the winding pitch of the strain sensing optical fiber, and μ is the Poisson's ratio of the circular plate support material; ΔR _i is the change in the radius of curvature caused by the macro bending of the single-turn strain sensing optical fiber, and R _i is the radius of curvature of the single-turn wound strain sensing optical fiber when the circular plate support is not bulging;

B3, repeat steps B1 to B2 until the bulging strain values ε _i of all the strain sensing optical fibers on the side of the circular plate support are calculated;

B4. Judge the health status of each circular plate bearing according to the change of the side bulging strain value ε _i of the circular plate bearing.

The data of the strain sensing optical fiber is obtained through the optical fiber signal analysis device, and then the strain sensing optical fiber is The relationship between the change in the single-circle curvature radius and the difference in optical power loss is used to indirectly calculate the bulging of the circular plate bearing at various positions on the side, and the uneven bulging of the entire circular plate bearing is obtained, which facilitates the conversion of the signal of the optical fiber signal analysis device into the bulging condition and facilitates calculation, thereby realizing online networking monitoring of multiple circular plate bearings, monitoring the health status of the bridge bearings in real time, and promptly discovering abnormal conditions of the bridge bearings.

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

1. The plate support of the present invention is spirally wound around the side of the circular plate support by the strain sensing optical fiber. When the annular side of the circular plate support bulges unevenly, the optical power loss of a single circle of the strain sensing optical fiber can be measured to simplify the calculation. The deformation amount is calculated using the relationship between the optical power loss and the fiber curvature radius, and the deformation of the side of the circular plate support is then monitored in real time. However, the existing monitoring instruments have poor performance in exposed environments, especially bridges in mountainous areas and cold regions. In cold and windy environments, monitoring instruments and sensors are easily damaged. The optical fiber of the present invention is placed in the support, has a small size, is easy to install, is not exposed to the environment, and has high durability. The material of the optical fiber itself makes it durable and stable for a long time. The internal signal transmission accuracy is high. Therefore, the present invention can continuously monitor with high precision and high durability, so as to understand the bulging defects and diseases of the circular plate support and carry out targeted on-site inspections and maintenance.

2. The monitoring system of the plate support of the present invention can realize real-time online health monitoring of massive supports within a limited cost, and can perform continuous monitoring over long distances and for long periods of time. Compared with existing monitoring, it reduces the heavy detection workload faced by detection technologies such as visual detection and point sensing, effectively saves the huge detection costs of emerging monitoring technologies such as video photography and drone telemetry, and provides data support for support maintenance. At the same time, the present invention can achieve expansion and replication, and facilitates networking and connection of multiple circular plate supports to form a self-perceiving monitoring system to obtain abnormal data in a short time.

3. The manufacturing method of the plate support of the present invention has a simple manufacturing process, convenient installation and operation, and has It has the durability to adapt to complex and harsh engineering environments, is easy to carry out on-site, and is convenient to connect when networking into a monitoring system. The networking connection is quick and easy.

4. The monitoring method of the monitoring system of the present invention is to arrange the strain sensing optical fiber on the circular plate support in a spiral winding manner, monitor the strain sensing optical fiber of the circular plate support at different positions through the optical fiber signal analysis device, and use the optical power loss as the indirect measurement physical quantity to realize real-time monitoring and calculation analysis of the uneven bulging of the bridge support, and obtain the uneven bulging condition of the entire circular plate support, so as to facilitate the conversion of the signal of the optical fiber signal analysis device into the bulging condition, facilitate calculation, realize online networking monitoring of multiple circular plate supports, monitor the health status of the bridge support in real time, and discover abnormal conditions of the bridge support in time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a plate-type support with self-sensing bulge according to the present invention;

FIG2 is a partial schematic longitudinal section of a circular plate support of the present invention;

FIG3 is a schematic diagram of a monitoring system for a plate-type support with self-sensing bulge according to the present invention;

FIG4 is a step diagram of a method for manufacturing a plate-type support with self-sensing bulge according to the present invention;

FIG. 5 is a step diagram of a monitoring method of a plate-type support monitoring system with bulge self-sensing according to the present invention.

Markings in the figure: 1-circular plate support; 2-strain sensing optical fiber; 3-transmission optical fiber; 4-optical fiber signal analysis device.

Detailed ways

The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments. The existing technologies all belong to the scope of the present invention.

Example 1

Please refer to Figure 1. This embodiment provides a bulge self-sensing plate support, which includes a circular plate support 1 and a strain sensing optical fiber 2. This embodiment is designed based on the existing circular plate support 1. The circular plate support 1 is made of rubber material. The circular plate support 1 is used for bridge construction. The top and bottom surfaces of the circular plate support 1 are circular surfaces, and its side surface is an annular side surface. The strain sensing optical fiber 2 is arranged on the annular side surface. The strain sensing optical fiber 2 is spirally wound on the annular side surface of the circular plate support 1. After winding, the strain sensing optical fiber 2 has a head end and a tail end reserved on the side surface of the circular plate support 1. The head end and the tail end The ends are respectively used for external connection. For example, when a network is connected, the strain sensing optical fibers 2 of different circular plate supports 1 can be connected through the head end and the tail end; through the circular plate support 1, the strain sensing optical fiber 2 can be smoothly wound into a spiral state. When the circular plate support 1 bulges unevenly, each single circle of the strain sensing optical fiber 2 loop around its vertical central axis generates optical power loss. By measuring the optical power loss value, real-time monitoring of the uneven bulging of the circular plate support 1 is achieved. By interpreting and analyzing the deformation situation, it is easy to understand the actual bulging situation of the circular plate support 1 and carry out targeted on-site inspection and maintenance.

Please refer to Figure 2. In this embodiment, the side of the circular plate support 1 is provided with a spiral groove around itself. The shape of the groove is set to facilitate the strain sensing optical fiber 2 to be spirally wound to form a spiral shape. The winding method can simplify the calculation and easily monitor the bulging condition of the circular plate support 1. The spiral groove is centered around the vertical center axis of the circular plate support 1. At a point on the side of the circular plate support 1 along the vertical direction, there is a gap between adjacent circles of the groove, and the gap distance is the winding pitch. The number of winding turns n of the strain sensing optical fiber 2 is in the range of [10, 15]. The number of winding turns is related to the winding radius, that is, the number of winding turns is related to the curvature radius of the winding. The number of winding turns forms the winding pitch. The denser the wound strain sensing optical fiber 2, the more winding turns there are. By setting the number of winding turns, sufficient light is guaranteed. The number of fiber winding turns is helpful for demodulating the optical fiber sensing signal, while avoiding excessive increase in the sensing gauge length and reducing the sensing performance; when winding, the optimal pitch can be determined by analyzing the total length change of the strain sensing optical fiber 2 under different winding turns. The principle is to minimize the total length change when the optical fiber is subjected to different strains. The analysis shows that the optimal ratio of winding radius to winding pitch is 1:2. However, due to the fact that the radius of the circular plate support 1 is much larger than the support height, the general radius can reach 700mm. It is not feasible to lay out the optical fiber according to the optimal ratio mentioned above. However, since the number of fiber winding turns essentially has little effect on the change of the total length of the optical fiber, after fully considering Under the premise of the purpose of the present invention, that is, to measure uneven bulging, a relatively dense layout is adopted to sense the radial deformation of different positions of the support, thereby achieving the purpose of measuring uneven bulging. Therefore, when the height of a general circular plate support 1 is 100-200 mm, 10-15 turns of optical fiber are laid out to sense the radial displacement of the support at more than 10 different height positions. By connecting the radial displacements at different positions into a straight line, it can be found that different radial displacements appear at those height positions. Through long-term observation, it can be determined which positions are most likely to be damaged, and then the bulging condition of the circular plate support 1 can be analyzed.

In this embodiment, the groove is used to embed the strain sensing optical fiber 2, and the depth of the groove is 1.5 to 2.5 mm, and 1.5 mm, 2.5 mm, or a value in between can be used. For example, 2.0 mm is used in this embodiment. The strain sensing optical fiber 2 is a single-mode optical fiber, and the outer diameter of the strain sensing optical fiber 2 is ≤1 mm. In this embodiment, the outer diameter of the strain sensing optical fiber 2 is 0.9 mm. The setting of the groove depth can provide sufficient embedding space for the strain sensing optical fiber 2, thereby enabling the strain sensing optical fiber 2 to be embedded in the side of the circular plate support 1; through the groove setting, it is ensured that the strain sensing optical fiber 2 can be embedded in the side of the circular plate support 1, so that it is convenient to wind it on the circular plate support 1. When the strain sensing optical fiber 2 is wound, the strain sensing optical fiber 2 is spirally wound around the side of the circular plate-type support 1 with the vertical central axis of the circular plate-type support 1 as the center. The strain sensing optical fiber 2 is wound multiple times on the side of the circular plate-type support 1 and fixed. By setting the single-mode optical fiber, it is convenient to set it on the side of the circular plate-type support 1, which can improve the optical fiber sensing accuracy; the strain sensing optical fiber 2 has a head end and a tail end for external connection. When the plate-type support of this embodiment is used for networking connection, the strain sensing optical fiber 2 The head end is connected to one end of the transmission optical fiber 3 , and the tail end of the strain sensing optical fiber 2 is connected to one end of another section of the transmission optical fiber 3 .

The plate support of the present embodiment also includes packaging glue, which is used for bonding. The strain sensing optical fiber 2 and the circular plate support 1 are fixed by the packaging glue. The packaging glue of the present embodiment adopts AB two-component epoxy resin glue. After the strain sensing optical fiber 2 is embedded in the groove, the head and tail ends of the strain sensing optical fiber 2 are reserved on the outside of both ends of the groove, and then the packaging glue is sealed in the groove. After the bonding is completed, a layer of packaging glue is coated on the side of the circular plate support 1; through the setting of the packaging glue, the strain sensing optical fiber 2 can be fixed, and at the same time, secondary protection is formed on the outside of the strain sensing optical fiber 2 to avoid damage caused by external loads on the optical fiber, thereby ensuring that the accuracy of the test is not affected.

Example 2

Please refer to Figure 3. This embodiment provides a monitoring system for a plate support with self-sensing bulge, which adopts the plate support with self-sensing bulge of Example 1. The monitoring system includes a circular plate support 1, a strain sensing optical fiber 2, a transmission optical fiber 3 and an optical fiber signal analysis device 4. The circular plate support 1 is used in bridge construction. Each bridge is provided with a plurality of different circular plate supports 1. The strain sensing optical fiber 2 is arranged on the circular plate support 1, and different circular plate supports 1 are networked and connected via the transmission optical fiber 3. The optical fiber signal analysis device 4 is connected via the transmission optical fiber 3. Through the transmission optical fiber 3, a plurality of circular plate supports 1 can be connected in series and connected to the optical fiber signal analysis device 4. The real-time optical power loss value of the strain sensing optical fiber 2 is measured by the optical fiber signal analysis device 4, which can provide data support for analyzing the bulge condition of the circular plate support 1, can perform real-time monitoring remotely, and realize online analysis of a large number of circular plate supports 1.

In this embodiment, the transmission optical fiber 3 adopts armored optical fiber, and different circular plate supports 1 are connected through the transmission optical fiber 3. One end of the transmission optical fiber 3 is connected to the head end of the strain sensing optical fiber 2, and one end of the other transmission optical fiber 3 is connected to the tail end of the strain sensing optical fiber 2. In this way, different circular plate supports 1 are connected in sequence. The circular plate type supports 1 are networked. After networking, the strain sensing optical fibers 2 of multiple circular plate type supports 1 are connected in series through the transmission optical fiber 3. After connection, they are connected to the optical fiber signal analysis device 4 through the transmission optical fiber 3. The optical fiber signal analysis device 4 has an input and an output end. The transmission optical fibers 3 at both ends are connected separately after networking. In this way, the strain sensing optical fibers 2 and the optical fiber signal analysis device 4 are connected in series. The optical fiber signal analysis device 4 and multiple strain sensing optical fibers 2 are connected in series through the transmission optical fiber 3 to form a loop. The armored optical fiber can protect the parts between different circular plate type supports 1 to prevent the optical fiber from being affected by external loads, thereby ensuring the transmission of optical fiber signals.

In this embodiment, the optical fiber signal analysis device 4 adopts an OTDR optical fiber power loss meter, which has a measurement wavelength range of 1310nm to 1550nm, a maximum single-mode measurement distance of 260km, a dynamic range of 36dB, a minimum single-mode pulse width of 3ns, an optical power loss resolution of 0.001dB, and a minimum single-mode sampling resolution of 0.04m. The measuring instrument is connected to the armored optical fiber through an FC/APC connector; an OTDR optical fiber power loss meter is used to test the optical power loss value of the optical fiber loop, and the bulge strain value at each position is calculated based on the relationship between the optical power loss value and the optical fiber winding length.

Example 3

Referring to FIG. 4 , this embodiment provides a method for manufacturing a plate-type support with self-sensing bulge. The method for manufacturing the plate-type support with self-sensing bulge in Embodiment 1 includes the following steps:

A1. Set a spiral groove that is wound around the circular plate support 1 for multiple turns on the annular side surface. When setting the groove, draw the groove along the side surface of the circular plate support 1 using ArtCAM engraving software so that the groove is centered on the vertical central axis of the circular plate support 1 and is spirally wound on the side surface of the circular plate support 1. After engraving is completed, use a cleaning solution to clean the groove.

A2. The strain sensing optical fiber 2 is laid tightly in the groove. During the laying, the strain sensing optical fiber 2 is stretched and laid by applying prestress. The strain sensing optical fiber 2 is stretched and laid by applying prestress. Finally, the straightened state is maintained, and the strain sensing optical fiber 2 is tightly laid in the groove along the extension path of the groove on the side of the circular plate support 1. After the strain sensing optical fiber 2 is laid out, the strain sensing optical fiber 2 is tested to ensure that the strain sensing optical fiber 2 is intact.

A3. Reserve a section of strain sensing optical fiber 2 outside the two ends of the groove, and use them as the head end and tail end of the strain sensing optical fiber 2 respectively. Inject packaging glue (AB two-component epoxy resin glue) into the groove to seal the groove. Connect the head end and tail end of the strain sensing optical fiber 2 of each circular plate support 1 to the end of the armored optical fiber respectively. Finally, apply a layer of packaging glue with a thickness of 0.5 to 1.5 mm on the side of the strain sensing optical fiber 2. The coating thickness can be 0.5 mm or 1.5 mm. The present embodiment adopts a thickness of 1.0 mm.

By first setting a groove on the side of the circular plate support 1, laying the strain sensing optical fiber 2, and finally encapsulating it with glue, the strain sensing optical fiber 2 can be combined on the basis of the circular plate support 1 to form an overall circular plate support 1 as a module, which is convenient for connection when networking into a monitoring system, and the networking connection is convenient and fast.

Example 4

Referring to FIG. 5 , this embodiment provides a monitoring method for a plate bearing monitoring system with self-sensing bulge, which adopts the plate bearing monitoring system with self-sensing bulge of Example 2. The circular plate bearing 1 is pre-set during bridge construction. The monitoring method includes the following steps:

B1. Measure the initial optical power loss value, actual optical power loss value and curvature radius change value of the single-turn strain sensing optical fiber 2 through the optical fiber signal analysis device 4. When the circular plate support 1 bulges unevenly, the single-turn wound strain sensing optical fiber 2 is stretched or compressed along with the uneven bulging of the circular plate support 1, causing the curvature radius of the single-turn strain sensing optical fiber 2 to change, thereby causing optical power loss in the loop of the strain sensing optical fiber 2. By measuring the optical power loss value of the optical fiber loop, it is convenient to indirectly calculate the uneven bulging of the circular plate support 1 by using the relationship between the optical power loss value and the curvature radius in the subsequent steps.

B2, calculating the bulging strain value ε _i of the circle of strain sensing optical fiber 2 at the side of the circular plate support 1 through the change value of the curvature radius of a single circle and the difference in optical power loss;

First, the calculation formula of the optical power loss caused by the macro bending of the single-turn winding of the strain sensing optical fiber 2 is obtained:
ΔB _i = Δα _i × ΔL _i

Wherein, ΔB _i is the optical power loss difference of a single turn strain sensing optical fiber 2 caused by the bulging on the outer side of the circular plate support 1, Δα _{i is} the macro bending loss coefficient of the strain sensing optical fiber 2, that is, the bending optical power loss difference per unit length of the strain sensing optical fiber 2, and ΔL _i is the macro bending length change value of the single turn strain sensing optical fiber caused by the bulging on the outer side of the circular plate support 1.

Among them, the properties of optical fiber are obtained:

Wherein, A and B are the calculation parameters of the macro bending loss coefficient of the strain sensing optical fiber 2, and A and B are obtained by the following formulas:

Wherein, λ is the wavelength measured by the optical fiber signal analysis device 4, λ _c is the cutoff wavelength of the strain sensing optical fiber 2, n ₁ and n ₂ are the refractive indices of the core and the cladding of the strain sensing optical fiber 2 respectively, and ΔR _i is the change in the curvature radius caused by the macroscopic bending of the single-turn strain sensing optical fiber 2.

According to the bulging deformation of the circular plate support 1, the curvature radius change value ΔR _i is obtained:
ΔR _i ＝ε _i R _i

Where R _i is the radius of curvature of a single-turn wound optical fiber when the support is not bulging, and ε _i is the bulging strain value of the support periphery at the position of the single-turn wound optical fiber.

The calculation formula for the length change of the macroscopic bending of a single-turn wound optical fiber caused by the bulging of the support periphery is as follows:

Where ΔL _i is the change in the macroscopic bending length of the optical fiber wrapped around the outer bulge of the support in a single circle, d is the winding pitch, r is the radius of the circular plate rubber support, and μ is the Poisson's ratio of the support material.

Substitute formula (3) and (4) into formula (2) to solve, and then combine formula (1), (2), (5) and (6), and according to the data measured by the optical fiber analysis device, obtain the bulging strain ε _i at any circumferential position outside the circular plate support 1. Simplified, it can be solved by the following formula:

ΔR _i ＝ε _i R _i

Among them, ΔB _i is the optical power loss difference of a single turn of strain sensing optical fiber 2 caused by the bulging of the outer side of the circular plate support 1, Δα _{i is} the macro bending loss coefficient of the strain sensing optical fiber 2, that is, the bending optical power loss difference of the strain sensing optical fiber 2 per unit length, r is the radius of the circular plate support 1, ε _i is the bulging strain value of the outer side of the circular plate support 1 at the position of the single turn of strain sensing optical fiber 2, d is the winding pitch of the strain sensing optical fiber 2, and μ is the Poisson's ratio of the material of the circular plate support 1; ΔR _i is the change in curvature radius caused by the macro bending of a single turn of strain sensing optical fiber 2, and R _i is the curvature radius of the single turn of strain sensing optical fiber 2 when the circular plate support 1 is not bulging.

B3, repeat steps B1 to B2 until the bulging strain values ε _i of all the circles of strain sensing optical fibers 2 on the side of the circular plate support 1 are calculated; according to the change of ε _i , the uneven bulging of the circular plate support 1 is obtained. Uneven strain distribution caused by convexity.

B4. According to the change of the side bulging strain value ε _i of the circular plate bearing 1, the health status of each circular plate bearing 1 is judged.

The data of the strain sensing optical fiber 2 is obtained through the optical fiber signal analysis device 4, and the bulging of each position on the side of the circular plate support 1 is indirectly calculated through the relationship between the single-turn curvature radius change value of the strain sensing optical fiber 2 and the optical power loss difference, so as to obtain the uneven bulging condition of the entire circular plate support 1, and conveniently convert the signal of the optical fiber signal analysis device 4 into the bulging condition, which is convenient for calculation, and realizes online networking monitoring of multiple circular plate supports 1, so as to monitor the health status of the bridge support in real time and promptly discover the abnormal condition of the bridge support.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A monitoring method for a plate support monitoring system with self-sensing bulges, characterized in that the monitoring system comprises a plate support with self-sensing bulges, a transmission optical fiber (3) and an optical fiber signal analysis device (4), wherein the plate support with self-sensing bulges comprises a circular plate support (1) and a strain sensing optical fiber (2), wherein the circular plate support (1) is pre-set during bridge construction, wherein the strain sensing optical fiber (2) is spirally wound around the side of the circular plate support (1) with the vertical center axis of the circular plate support (1) as the center, wherein the strain sensing optical fiber (2) is wound around the side of the circular plate support (1) for multiple turns and fixed, wherein the strain sensing optical fiber (2) has a head end and a tail end for external connection, wherein the head end (21) of the strain sensing optical fiber (2) is connected to one end of the transmission optical fiber (3), and the tail end (22) of the strain sensing optical fiber (2) is connected to one end of another section of the transmission optical fiber (3); and the optical fiber signal analysis device 4 is connected via the transmission optical fiber 3;

   The monitoring method includes the following steps:

   B1, measuring the initial optical power loss value, the actual optical power loss value and the curvature radius change value of a single turn of the strain sensing optical fiber (2) by means of the optical fiber signal analysis device (4);

   B2. Calculate the bulging strain value ε _i of the strain sensing optical fiber (2) on the side of the circular plate support (1) through the change value of the curvature radius of a single circle and the difference in optical power loss:
   
   ΔR _i ＝ε _i R _i

   Wherein, ΔB _i is the optical power loss difference of a single turn of the strain sensing optical fiber (2) caused by the bulging of the outer side of the circular plate support (1), Δα _i is the macro bending loss coefficient of the strain sensing optical fiber (2), that is, the bending optical power loss difference of the strain sensing optical fiber (2) per unit length, r is the radius of the circular plate support (1), ε _i is the bulging strain value of the outer side of the circular plate support (1) at the position of the single-turn wound strain sensing optical fiber (2), d is the winding pitch of the strain sensing optical fiber (1), and μ is the Poisson's ratio of the material of the circular plate support (1); ΔR _i is The change in the radius of curvature caused by the macroscopic bending of a single-turn strain sensing optical fiber (1), R _i is the radius of curvature of the single-turn strain sensing optical fiber (2) when the circular plate support (1) is not bulging;

   B3, repeating steps B1 to B2 until the bulging strain values ε _i of all the circles of strain sensing optical fibers (2) on the side of the circular plate support (1) are calculated;

   B4. According to the change of the bulging strain value ε _i of the side of the circular plate bearing (1), the health status of each circular plate bearing (1) is judged.
2. The monitoring method of the bulge self-sensing plate support monitoring system according to claim 1 is characterized in that the strain sensing optical fiber (2) is a single-mode optical fiber, and the outer diameter of the strain sensing optical fiber (2) is ≤1 mm.
3. The monitoring method of the bulge self-sensing plate support monitoring system according to claim 2 is characterized in that the number of winding turns n of the strain sensing optical fiber (2) is in the range of [10, 15].
4. The monitoring method of the bulge self-sensing plate support monitoring system according to claim 1 is characterized in that the side of the circular plate support (1) is provided with a spiral groove surrounding itself, and the groove is used to embed the strain sensing optical fiber (2).
5. The monitoring method of the bulge self-sensing plate support monitoring system according to claim 4 is characterized in that the depth of the groove is 1.5 to 2.5 mm.
6. The monitoring method of the bulge self-sensing plate support monitoring system according to claim 1 is characterized in that it also includes packaging glue, and the strain sensing optical fiber (2) and the circular plate support (1) are fixed by the packaging glue.
7. The monitoring method of the plate-type bearing monitoring system with bulge self-sensing according to claim 1 is characterized in that the plate-type bearing monitoring system with bulge self-sensing comprises a plurality of the circular plate-type bearings (1), The head ends and tail ends of the strain sensing optical fibers (2) of the plurality of circular plate supports (1) are respectively connected to transmission optical fibers (3), and the optical fiber signal analysis device (4) and the plurality of strain sensing optical fibers (2) are connected in series via the transmission optical fibers (3) to form a loop.
8. According to the monitoring method of the monitoring system of the bulge self-sensing plate support according to claim 7, it is characterized in that the transmission optical fiber (3) adopts armored optical fiber.