A track scale based on fiber grating sensor and load measurement method

Abstract

The present invention provides a track scale based on a fiber optic Bragg grating sensor, which includes a sensor module, a sensing fiber, a transmission optical cable, and a computing unit. The sensor module includes a base and a translation hinge structure. The translation hinge structure includes a translation table that translates relative to the base and at least two connecting rods. One end of the connecting rod is hinged to the base, and the other end is hinged to the translation table. The sensing fiber is fixed to the base and the translation table along the direction in which the translation table can translate relative to the base. The translation hinge structure can drive the sensing fiber to translate under the action of deformation. One end of the transmission optical cable is connected to the sensing fiber, and the other end is connected to the computing unit. The present invention also provides a load measurement method. In the present invention, the track scale based on the fiber optic Bragg grating sensor has high measurement accuracy, is easy to install, has a stable structure, a long service life, and is highly safe.

Description

Technical Field

[0001] The present invention relates to the field of railway detection technology, and in particular to a track scale based on a fiber grating sensor and a load measurement method. Background Art

[0002] As my country's primary mode of freight transportation, railways are a vital component of the country's logistics and transportation system, offering safety, reliability, high capacity, and low costs. However, due to limitations in various factors, railway freight cars have long suffered from overloading, uneven loading, and overweighting. This not only damages rolling stock, significantly reducing its service life and even endangering driving safety, but also severely harms railway lines and switches, posing a significant threat. By monitoring the wheel load on railway freight cars, we can promptly determine whether trains are overloaded, unevenly loaded, or overweighted, effectively preventing accidents.

[0003] Common detection methods require the deployment of electronic equipment such as track electronic pressure sensors or ground sensing coils for assistance. However, during the measurement process, electrical sensors are susceptible to external electromagnetic interference and have cumbersome wiring. They also have defects such as zero drift and temperature drift, which cannot meet the application requirements of long-term, long-distance, and real-time monitoring in harsh environments. Fiber Bragg gratings are widely used in health monitoring due to their resistance to electromagnetic interference, small size, and easy networking. Shear force sensors using fiber Bragg gratings as sensitive elements have broad prospects in track scale detection applications. Currently, there are three types of mechanical principles that can be used in track scales: normal stress type, bending moment type, and shear force type. The commonly used shear force track scale uses an insert-type shear sensor embedded in the hole of the rail web to form a double I-beam system. The rail and shear force sensor are connected by interference fit to form an integrated sensor matrix to transmit the weight of the wheel.

[0004] However, during the drilling process of traditional shear-type track scales, factors such as the position and roughness of the hole, as well as the interference fit between the hole position and the shear sensor, directly affect the measurement accuracy of the shear sensor. High requirements are placed on the accuracy and standardization of the installation operation. Once the drilling fails, the rail needs to be replaced, which is difficult to operate and requires a lot of work. Summary of the Invention

[0005] In view of this, it is necessary to provide a track scale and load measurement method based on fiber optic Bragg grating sensors to solve the problems of accuracy of measurement results and stability of measurement systems of track scales in the existing technology.

[0006] The present invention provides a railway scale based on a fiber grating sensor, comprising:

[0007] A sensor module, a sensing optical fiber, a transmission optical cable, and a computing unit. The sensor module includes a base and a translation hinge structure. The translation hinge structure includes a translation platform that translates relative to the base and at least two connecting rods. One end of the connecting rod is hinged to the base, and the other end is hinged to the translation platform. The sensing optical fiber is fixed to the base and the translation platform along the direction in which the translation platform can translate relative to the base. The translation hinge structure can drive the sensing optical fiber to translate under the action of deformation. One end of the transmission optical cable is connected to the sensing optical fiber, and the other end is connected to the computing unit. The computing unit obtains real-time wavelength data of the sensing optical fiber through the transmission optical cable to measure the wheel load.

[0008] Optionally, the base includes a bottom plate, one end of the connecting rod away from the translation table is hinged to the bottom plate, the bottom plate extends to form fixed brackets located at both ends of the translation direction of the translation table, and the sensing optical fiber is fixed to the fixed brackets.

[0009] Optionally, the connecting rod is hinged to the base plate and the translation table via a flexible hinge.

[0010] Optionally, the sensing optical fiber includes a first fiber grating and a second fiber grating, and the first fiber grating and the second fiber grating are symmetrically arranged to form a differential structure.

[0011] Optionally, one end of the first fiber Bragg grating is fixed to the translation table, and the other end of the first fiber Bragg grating is fixed to one of the fixed brackets; one end of the second fiber Bragg grating is fixed to the translation table, and the other end of the second fiber Bragg grating is fixed to another fixed bracket.

[0012] Optionally, at least two sensor modules are included that can be spaced apart.

[0013] Optionally, the sensor module is made of stainless steel and is integrally formed by wire cutting.

[0014] The present invention also provides a load measurement method based on any of the above-mentioned fiber grating sensor-based railway scales, comprising the steps of:

[0015] The sensor modules are respectively arranged on both sides of the rail waist, and the two sensor modules are symmetrical about the center of the rail waist;

[0016] The two sensor modules detect real-time wavelength data when a vehicle passes by;

[0017] The load is calculated based on the real-time wavelength data detected.

[0018] Optionally, the step of calculating the load based on the detected real-time wavelength data includes:

[0019] Establishing shear force models at the two sensor modules respectively;

[0020] obtaining a first shear force curve and a second shear force curve corresponding to the two sensor modules respectively according to the real-time wavelength data detected by the two sensor modules;

[0021] Obtaining a wavelength variation difference curve according to the first shear force curve and the second shear force curve;

[0022] Differentiating the wavelength variation curve to obtain a wavelength variation difference curve;

[0023] The load is calculated based on the shear force model and the wavelength variation difference curve.

[0024] Optionally, the step calculates the load according to the shear force model and the wavelength variation difference curve. The calculation formula of the load is:

[0025]

[0026] in, is the shear modulus of the rail; is the static distance of the rail section to the center axis; is the moment of inertia of the rail about the central axis; is the gauge factor of the fiber Bragg grating; is the bonding distance of the fiber Bragg grating; A wavelength change detected by the sensor module; is the wavelength change detected by another sensor module, b is the waist thickness of the rail; and H is the horizontal length of the shear force sensor.

[0027] The beneficial effects of the present invention are:

[0028] In the present invention, the base and the translation table are hingedly connected to form a parallelogram mechanism by the connecting rod. The deformation of the parallelogram mechanism causes the translation table to undergo large-scale translation and small-scale rotation. The wheel load is calculated through the wavelength data of the sensing optical fiber. The track scale based on the fiber optic Bragg grating sensor only needs to be glued and fixed to the rail without drilling holes in the rail, which greatly reduces the difficulty of installation and improves the accuracy of the measurement results and the stability of the measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 Schematic diagram of the structure of the railway scale based on the fiber grating sensor in the present invention;

[0031] Figure 2 for Figure 1 Schematic diagram of the structure of the sensor module;

[0032] Figure 3 This is a schematic diagram of the sensor module;

[0033] Figure 4 2. It is a schematic diagram of wheel-rail coupled motion analysis in an embodiment of the present invention;

[0034] Figure 5 2. It is a schematic diagram of the wheel-rail coupling force analysis in an embodiment of the present invention;

[0035] Figure 6 2 is a schematic diagram of a wavelength variation curve according to an embodiment of the present invention;

[0036] Figure 7 is a schematic diagram of shear strain according to an embodiment of the present invention;

[0037] Figure 8 2 is a schematic diagram of a wavelength variation difference curve during driving according to an embodiment of the present invention;

[0038] Among them: 1-base, 11-bottom plate, 12-fixed bracket, 2-double-rod four-hinge structure, 21-translational table, 22-connecting rod, 3-sensing optical fiber, 4-transmission optical cable, 5-computing unit. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0040] like Figure 1 、 Figure 2As shown, an embodiment of the present invention provides a track scale based on a fiber grating sensor, which includes: a sensor module, a sensing fiber 3, a transmission optical cable 4, and a computing unit 5. The sensor module includes a base 1 and a translation hinge structure 2. The translation hinge structure 2 includes a translation table 21 that translates relative to the base and at least two connecting rods 22. One end of the connecting rod 22 is hinged to the base 1, and the other end is hinged to the translation table 21. The sensing fiber 3 is fixed to the base 1 and the translation table 21 along the direction in which the translation table 21 can translate relative to the base 1. The translation hinge structure 12 can drive the sensing fiber 3 to translate under the action of deformation. One end of the transmission optical cable 4 is connected to the sensing fiber 3, and the other end is connected to the computing unit 5. The computing unit 5 obtains real-time wavelength data of the sensing fiber 3 through the transmission optical cable 4 to achieve measurement of wheel load.

[0041] In the present invention, the base 1 and the translation table 21 are hingedly connected with the connecting rod 22 to form a parallelogram mechanism. The deformation of the parallelogram mechanism causes the translation table 21 to undergo large-scale translation and small-scale rotation. The wheel load is calculated by the wavelength data of the sensing optical fiber 3. The track scale based on the fiber optic Bragg grating sensor only needs to be glued and fixed to the rail, without drilling holes in the rail, which greatly reduces the difficulty of installation and improves safety.

[0042] Specifically, the base 1 , the translation table 21 and the connecting rod 22 are made of stainless steel and are integrally formed by wire cutting, which is a simple process.

[0043] It should be noted that the fiber Bragg grating sensor-based track scale of the present invention requires the sensor to be fixed to the structure being measured in its sensitive direction during measurement. Fixing methods include, but are not limited to: applying structural adhesive to the bottom surface of the fiber Bragg grating sensor base 1 and the side of the translation stage 21, and affixing them to the structure being measured; and connecting the side of the fiber Bragg grating sensor to the rail structure using a custom fixture. Compared to the existing drilling installation method of track scales, the solution provided by the present invention is simpler and faster to install.

[0044] Specifically, the base 1 includes a bottom plate 11, and the end of the connecting rod 22 away from the translation table 21 is hinged to the bottom plate 11. The bottom plate 11 extends to form fixed brackets 12 located at both ends of the translation direction of the translation table 21, and the sensing optical fiber 3 is fixed to the fixed brackets 12.

[0045] Furthermore, a fixing surface for fixing the sensing optical fiber 3 is provided at the upper end of the fixing bracket 12 , and the fixing surface and the fixing surface of the translation stage 21 in the natural state are located in the same plane.

[0046] Specifically, the length direction of the translation table 21 is parallel to the length direction of the base plate 11, one end of one connecting rod 22 is hinged to one end of the translation table 21, and the other end of the connecting rod 22 is hinged to the base plate 11, and one end of another connecting rod 22 is hinged to the other end of the translation table 21, and the other end of the connecting rod 22 is hinged to the base plate 11.

[0047] It should be noted that the connection between the connecting rod 22 and the base plate 11 and the translation platform 21 is achieved through flexible hinges. In this embodiment, there are four flexible hinges, which are respectively provided at the two ends of the two connecting rods 22.

[0048] Specifically, the sensing fiber 3 comprises a first fiber Bragg grating (FBG) and a second fiber Bragg grating (FBG), which are symmetrically arranged to form a differential structure. During operation, the translation stage 21 translates, causing the pre-stretched FBG to undergo axial extension and compression. This axial extension and compression results in equal and opposite wavelength shifts in the first and second FBGs. Differentiating the two shifts doubles the sensor's sensitivity while also achieving temperature compensation.

[0049] Furthermore, one end of the first fiber Bragg grating is fixed to the translation table 21, and the other end of the first fiber Bragg grating is fixed to one of the fixed brackets 12; one end of the second fiber Bragg grating is fixed to the translation table 21, and the other end of the second fiber Bragg grating is fixed to another fixed bracket 12.

[0050] It should be noted that the first and second fiber Bragg gratings need to be pre-tensioned before being fixed to effectively sense negative strain. There are various ways to fix the first and second fiber Bragg gratings. In this embodiment, the first and second fiber Bragg gratings are fixed to the fixing bracket 12 and the translation stage 21 using epoxy resin glue.

[0051] The working principle of a track scale based on a fiber grating sensor of the present invention is as follows: the sensor is fixed to the rail structure. When the rail structure is subjected to the load of the wheel, the sensor deforms along the deformation direction along with the structure being measured. The parallelogram mechanism composed of the two connecting rods 22 and four flexible hinges causes the translation platform 21 to translate, thereby causing the first fiber grating and the second fiber grating subjected to pre-tensioned stress to undergo axial stretching and axial compression. This axial stretching and compression causes the first fiber grating and the second fiber grating to produce wavelength drifts of equal magnitude and opposite directions. By differentiating the two, the sensor sensitivity can be doubled, and temperature compensation can be achieved at the same time. The transmission cable 4 imports real-time wavelength data into the calculation unit 5. The calculation unit 5 obtains a wavelength change curve at the measuring point based on the real-time wavelength data, then obtains a wavelength change difference curve based on the wavelength change curve, and finally calculates and weighs according to the wavelength change difference curve.

[0052] The present invention also provides a load measurement method based on the fiber grating sensor-based railway scale, comprising the steps of:

[0053] S1. Arrange the sensor modules on both sides of the rail waist, with the two sensor modules symmetrically positioned about the center of the rail waist;

[0054] S2, the two sensor modules detect real-time wavelength data when a vehicle passes by;

[0055] S3. Calculate the load according to the detected real-time wavelength data.

[0056] Specifically, step S3, calculating the load according to the detected real-time wavelength data, includes:

[0057] S31, establishing shear force models at the two sensor modules respectively;

[0058] S32. Obtaining a first shear force curve and a second shear force curve corresponding to the two sensor modules respectively according to the real-time wavelength data detected by the two sensor modules;

[0059] S33, obtaining a wavelength change difference curve according to the first shear force curve and the second shear force curve;

[0060] S34, performing differentiation on the wavelength variation curve to obtain a wavelength variation difference curve;

[0061] S35. Calculate the load based on the shear force model and the wavelength variation difference curve.

[0062] Furthermore, in step S35, the calculation formula for the load in the load is calculated according to the shear force model and the wavelength change difference curve:

[0063]

[0064] in, is the shear modulus of the rail; is the static distance of the rail section to the center axis; is the moment of inertia of the rail about the central axis; is the gauge factor of the fiber Bragg grating; is the bonding distance of the fiber Bragg grating; A wavelength change detected by the sensor module; is the wavelength change detected by another sensor module, b is the waist thickness of the rail; and H is the horizontal length of the shear force sensor.

[0065] To better illustrate the advantages of the present invention, a model analysis is now conducted on the railway scale based on the fiber grating sensor provided by the present invention:

[0066] like Figure 3 As shown, two connecting rods 22 and four flexible hinges form a parallelogram mechanism. Under the action of , the translation table 21 undergoes large-scale translation and small-scale rotation. Assume that the center distance between the two flexible hinges in the same plane is , the translation displacement of the translation table 21 is , the rotational displacement is From the geometric relationship, we can get:

[0067]

[0068]

[0069] When the center distance between the two flexible hinges is , the translation displacement of the translation table 21 is When , the rotation displacement of the translation table 21 is Only .

[0070] The track scale can optimize the system design based on the following theoretical model.

[0071] Analysis of track scale:

[0072] like Figure 4 、 Figure 5As shown in the figure, when a train passes through the rail, the force analysis of the detection point is as follows: the area between the two sleepers AB is regarded as the monitoring area, the sensor module 1 is arranged on the left side of the center of the rail waist, and this is designated as measurement point 1, and the sensor module 2 is arranged on the right side of the center of the rail waist, and this is designated as measurement point 2. Measurement points 1 and 2 are symmetrical about the center of the rail waist. When the wheels pass through the monitoring area in different directions, the shear force of the cross section of measurement points 1 and 2 is The mechanical analysis is also different. Figure 4 and Figure 5 In the example, S1 and S2 are used to represent measuring point 1 and measuring point 2 respectively. The wavelength variation curves at measuring point 1 and measuring point 2 correspond to wavelength variation curve S1 and wavelength variation curve S2 respectively. After obtaining the wavelength variation at each measuring point, the calculation unit draws the wavelength variation curve S1 according to the change of the wavelength variation over time. Figure 6 The wavelength variation curve is shown.

[0073] Consider a section of rail between two sleepers A and B as a simply supported beam. When the wheel travels on the rail from end A to end B (hereinafter referred to as forward travel), according to the mechanics principle of the beam, first analyze the position where the wheel does not pass through the measuring point. The simply supported beam is in equilibrium under the external force of the wheel. According to the static equilibrium equation, the support reaction force can be calculated as follows:

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] have to

[0080]

[0081]

[0082]

[0083] in, is the resultant force in the X direction, is the resultant force in the Y direction, is the total moment at point A, is the upward support reaction force at point A, is the upward support reaction at point B, is the wheel load, is the distance from the bottom of the wheel to be tested to point A, is the distance between two points AB.

[0084] When analyzing measuring point 1, use the cross section to cut the beam into two sections at the measuring point, such as Figure 6 As shown, the left beam section is taken as the detached body. Since the beam was originally in equilibrium, the detached left beam section also maintains equilibrium. The left beam section has an upward support reaction force and a downward wheel load P. To prevent the left beam section from moving vertically, a vertical internal force must exist on the cross section to balance it.

[0085]

[0086] in, is the shear force at measuring point 1.

[0087] From the above analysis, we can see that when the cross-section method is used to cut the beam into two sections, the internal forces on the same cross section are equal when the left section of the beam is taken as the detached body and the right section of the beam is taken as the detached body, but the directions are opposite. Therefore, the positive and negative signs of the internal forces are determined according to the deformation of the beam caused by the shear force. At the cross section, if a small section is taken out from the beam, if the shear force causes the micro-section to rotate clockwise, the shear force on the cross section is positive; otherwise, it is negative. Therefore, when the bottom of the wheel does not pass through the measuring point, the shear force on the cross section of the measuring point is The relationship between it and the wheel load P is:

[0088] Similarly, when the wheel passes through the measuring point, the shear force of the cross section of the measuring point is The relationship between it and the wheel load P is:

[0089]

[0090] like Figure 7 As shown, when the rail is subjected to shear force When the shear force sensor is attached to the surface with the shear stress Shear deformation generates shear strain .

[0091]

[0092] in, is the shear modulus of the rail; is the static distance of the rail section to the center axis; is the moment of inertia of the rail about the central axis; is the waist thickness of the rail.

[0093] Shear strain is the tilt angle The tangent value of the shear strain can be Expressed as

[0094]

[0095] In the above formula, The displacement difference between the translation table and the base caused by shear deformation; is the horizontal length of the shear sensor.

[0096] And satisfy:

[0097]

[0098] In the above formula, is the stretching distance of the first fiber grating or the compression distance of the second fiber grating.

[0099] The strains generated by the first fiber Bragg grating and the second fiber Bragg grating are equal and opposite, that is, , and under the same temperature field, the wavelength changes of the two fiber Bragg gratings are differentiated to obtain

[0100]

[0101] In the formula is the gauge factor of the fiber Bragg grating. When the central wavelength of the fiber Bragg grating is in the 1500nm band, .

[0102] It can be obtained that when the bottom of the wheel does not pass through the measuring point 1, the wavelength change of the measuring point 1 is The relationship between it and the wheel load P is:

[0103]

[0104] Similarly, when the wheel passes through the measuring point 1, the wavelength change of the measuring point 1 is The relationship between it and the wheel load P is:

[0105]

[0106] For measuring point 2, when the wheel does not pass through or passes through measuring point 2, the wavelength change at measuring point 2 and the cross section The relationship between it and the wheel load P is the same as that at measuring point 1.

[0107] The wavelength variation curve includes a first shear force curve and a second shear force curve; the wavelength variation difference curve = the first wavelength variation curve - the second wavelength variation curve. That is, V = S1 - S2. After obtaining the wavelength variation curve, the wavelength variation difference curve can be obtained by differentiating the wavelength variation curves.

[0108] like Figure 8 As shown, the wavelength variation difference curve is a horizontal curve, and it can be obtained by calculation that the wheel load P and the wavelength variation The relationship between them is:

[0109]

[0110] The beneficial effects of the present invention are:

[0111] 1. The present invention provides a track scale based on a fiber Bragg grating sensor. The two connecting rods and the four flexible hinges form a parallelogram mechanism. The deformation of the parallelogram mechanism causes the translation table to undergo large-scale translation and small-scale rotation, significantly reducing the bending deformation of the fiber Bragg grating and improving the fatigue strength of the fiber Bragg grating, thereby increasing the service life of the fiber Bragg grating sensor. The track scale based on the fiber Bragg grating sensor only needs to be glued and fixed to the rails, without the need to drill holes in the rails, which greatly reduces the difficulty of installation and also improves safety.

[0112] 2. The present invention establishes a mathematical model for a railway scale based on a fiber Bragg grating sensor, which can optimize the design of parameters such as the hinge size and installation position of the sensor to meet the requirements of railway scales in different applications. The railway scale has good application prospects.

[0113] 3. The sensor of the present invention symmetrically arranges two fiber gratings on the translation stage. The center wavelength drifts of the two fiber gratings are equal in magnitude and opposite in direction. Differentiating the two can eliminate the influence of temperature changes and improve the sensitivity of the sensor.

[0114] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A railroad scale based on a fiber grating sensor, characterized in that: include: A sensor module, a sensing fiber, a transmission optical cable, and a computing unit. The sensor module includes a base and a translation hinge structure. The translation hinge structure includes a translation table that translates relative to the base and at least two connecting rods. One end of the connecting rod is hinged to the base, and the other end is hinged to the translation table. The sensing fiber is fixed to the base and the translation table along the direction in which the translation table can translate relative to the base. The translation hinge structure can drive the sensing fiber to translate under the action of deformation. One end of the transmission optical cable is connected to the sensing fiber, and the other end is connected to the computing unit. The computing unit obtains real-time wavelength data of the sensing fiber through the transmission optical cable to measure the wheel load. The sensing fiber includes a first fiber grating and a second fiber grating. The first fiber grating and the second fiber grating are symmetrically arranged to form a differential structure.

2. The railroad scale based on fiber grating sensor according to claim 1, characterized in that: The base includes a bottom plate, one end of the connecting rod away from the translation table is hinged to the bottom plate, the bottom plate extends to form fixed brackets respectively located at both ends of the translation direction of the translation table, and the sensing optical fiber is fixed to the fixed brackets.

3. The railroad scale based on fiber grating sensor according to claim 2, characterized in that: The connecting rod is hinged to the base plate and the translation platform through a flexible hinge.

4. The railroad scale based on a fiber Bragg grating sensor according to claim 1, characterized in that: One end of the first fiber Bragg grating is fixed to the translation table, and the other end of the first fiber Bragg grating is fixed to one of the fixing brackets; one end of the second fiber Bragg grating is fixed to the translation table, and the other end of the second fiber Bragg grating is fixed to another fixing bracket.

5. The railroad scale based on fiber grating sensor according to claim 1, characterized in that: The device comprises at least two sensor modules that can be spaced apart from each other.

6. The railroad scale based on fiber grating sensor according to claim 1, characterized in that: The sensor module is made of stainless steel and is integrally formed by wire cutting.

7. A method for measuring wheel load, based on the track scale based on fiber grating sensor according to any one of claims 1 to 6, characterized in that: Including steps: The sensor modules are respectively arranged on both sides of the rail waist, and the two sensor modules are symmetrical about the center of the rail waist; The two sensor modules detect real-time wavelength data when a vehicle passes by; The load is calculated based on the real-time wavelength data detected.

8. The method for measuring wheel load according to claim 7, wherein: The steps for calculating the load based on the detected real-time wavelength data include: Establishing shear force models at the two sensor modules respectively; obtaining a first shear force curve and a second shear force curve corresponding to the two sensor modules respectively according to the real-time wavelength data detected by the two sensor modules; Obtaining a wavelength variation difference curve according to the first shear force curve and the second shear force curve; Differentiating the wavelength variation curve to obtain a wavelength variation difference curve; The load is calculated based on the shear force model and the wavelength variation difference curve.

9. The method for measuring wheel load according to claim 8, wherein: Step 1: The calculation formula for calculating the load in the load is as follows based on the shear force model and the wavelength change difference curve: in, is the shear modulus of the rail; is the static distance of the rail section to the center axis; is the moment of inertia of the rail about the central axis; is the gauge factor of the fiber Bragg grating; is the bonding distance of the fiber Bragg grating; A wavelength change detected by the sensor module; is the wavelength change detected by another sensor module, b is the waist thickness of the rail; and H is the horizontal length of the shear force sensor.

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