A method for calculating the static rigidity of a continuous railway track field fastener assembly

Abstract

The application discloses a continuous railway track field fastener assembly static stiffness calculation method, comprising the following steps: installing a fastener assembly static stiffness detection device; loading the center of a fastener node on a rail to collect force and displacement information of n fastener nodes; establishing a mathematical model of a continuous long rail and the fastener nodes; establishing a corresponding relationship between the loading force of the rail and the stress at the fastener nodes; performing iterative calculation of the assembly static stiffness at the fastener nodes; drawing a force-displacement curve and a stiffness curve; wherein the fastener assembly static stiffness detection device is arranged to be fixed on the railway track and capable of applying a vertical load to the rail and measuring the vertical displacement of the rail at the fastener node position. The application reflects the assembly state of the fastener in the current continuous line in real time, and improves the detection status of high cost of single piece and small batch in the laboratory.

Description

Technical Field

[0001] This invention relates to the field of track inspection, and more specifically, to a method for calculating the static stiffness of on-site fastener assembly for continuous railway tracks. Background Technology

[0002] Based on the current fastening systems used in my country's railways, these systems are divided into high-speed railway fastening systems and conventional railway fastening systems. High-speed railways primarily use WJ-7, WJ-8, and Vosssloh300-1 fasteners, as well as elastic clip type IV, elastic clip type V, FC, and SFC fasteners. Conventional railways mainly use 70-type plate fasteners, elastic clip type I, elastic clip type II, and elastic clip type III fasteners, which are mostly used in ballasted tracks. The assembly stiffness of a fastener refers to the vertical force required to generate a unit vertical displacement of the rail on the fastener assembly. It reflects the real-time working status of the fastener on the rail, and therefore, its detection can reflect the real-time health status of the railway line.

[0003] Currently, the static stiffness testing of fastening systems is mainly conducted in a laboratory environment according to the People's Republic of China Railway Industry Standard TB / T3396.3-2015 "Test Methods for Fastening Systems of High-Speed ​​Railways Part 3: Determination of Assembly Static Stiffness". The main testing instruments include rails, loading equipment, displacement sensors, load sensors, and recording equipment. The test specimens include sleepers and fasteners. The specific principle involves applying a load perpendicular to the bottom surface of the rail (assembled on a single rail bearing surface) to the assembled fastening system using a testing machine, and measuring the displacement of the rail relative to the sleeper under the load.

[0004] The static stiffness of fastener assembly under this method can only be tested for a single fastener group. At the same time, laboratory testing suffers from problems such as long transportation time and high cost, and cannot reflect the actual working status of continuous fastener clamping on the railway track in real time. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating the static stiffness of on-site fastener assembly for continuous railway tracks. This method can be used to plot force-displacement curves and stiffness curves, thereby reflecting the assembly status of fasteners in the current continuous track in real time and improving the current situation of high cost for single-piece and small-batch testing in the laboratory.

[0006] To achieve the above objectives, the present invention provides a method for calculating the static stiffness of on-site fastener assembly for continuous railway tracks, which includes the following steps:

[0007] S500, a device for detecting the static stiffness of fastener components;

[0008] S510, load is applied at the center of the rail at the fastener node, and force and displacement information of n fastener nodes is collected;

[0009] S520, establish a mathematical model for continuous long rails and fastener nodes;

[0010] S530, establish the correspondence between the rail loading force and the force at the fastener node;

[0011] S540, perform iterative calculation of the static stiffness of the assembly at the fastener node;

[0012] S550, plot force-displacement curves and stiffness curves;

[0013] The static stiffness testing device for the fastener assembly is configured to be fixed on the railway track and capable of applying a vertical load toward the rail, as well as measuring the vertical displacement of the rail at the fastener node position.

[0014] Preferably, in step S510, after calibrating the displacement sensor and the loading device facing the rail, a load is applied to the rail, and at each fastener node, the load is applied over time. The changes correspond to different loading forces. Until it is loaded to a fixed value Loading then stops.

[0015] Preferably, in step S530, the load applied to each fastener node is recorded. and displacement at time and ,in, , Then, continuous rail loading force is applied. and the actual load force separated to a single fastener The establishment of the mathematical model will apply the force. and The load force transmitted to each fastener node in the continuous track is obtained through calculations performed using the established mathematical model in the analysis component. and ,in, .

[0016] Preferably, in step S540, the calculated loading force is... and and the displacement of the corresponding nodes. and And obtain an assembly static stiffness according to the stiffness calculation formula. The value is then determined based on the obtained assembly static stiffness. Values ​​and displacements Then, the loading force of the fastener is iterated in reverse through the established continuous track model. This process is repeated, iterating continuously to approach the true reality. Value and value.

[0017] Preferably, steps S510-S540 are repeated multiple times, with a pause of 3-10 seconds after each unloading. Continue loading, and use the average value of multiple tests as the static stiffness of the fastener assembly.

[0018] Preferably, the static stiffness detection device for the fastener assembly includes: a displacement sensor, a data acquisition component, an online detection and analysis component, a support frame, and a hydraulic jack mounted on the support frame for applying a vertical load to the rail. A loading platform is provided between the hydraulic jack and the rail, and a pressure sensor is provided between the loading platform and the hydraulic jack.

[0019] Preferably, the hydraulic jack is a hollow hydraulic jack, the pressure sensor is a hollow pressure sensor, and the loading platform is provided with a rod shaft that can pass through the hollow pressure sensor, the hollow hydraulic jack, and the support frame in sequence.

[0020] Preferably, the support frame includes a portal frame and U-shaped support plates disposed at both ends of the portal frame, and the U-shaped support plates are provided with through holes for mounting spiral rail spikes.

[0021] Preferably, the two ends of the portal frame are provided with U-shaped grooves for avoiding the spiral rail spike, and the outer edges of the two ends of the portal frame are provided with mounting seats for installing fastening bolts. The mounting seats, U-shaped grooves and spiral rail spikes at the same end are displaced on the same plane.

[0022] Preferably, the mounting holes on the portal frame corresponding to the fastening bolts are elongated holes extending along the length of the parallel rail.

[0023] According to the above technical solution, the present invention can draw force-displacement curves and stiffness curves based on the static stiffness calculation method of the on-site fastener assembly of continuous railway tracks, thereby reflecting the assembly status of fasteners in the current continuous line in real time and improving the current situation of high cost of single-piece and small-batch testing in the laboratory.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0026] Figure 1This is a schematic diagram of the calculation method for the static stiffness of on-site fastener assembly of continuous railway tracks;

[0027] Figure 2 It is a mathematical model of continuous track on railway site;

[0028] Figure 3 This is a static stiffness test diagram of the continuous railway track fastener assembly on site in Example 1;

[0029] Figure 4 This is a static stiffness test diagram of the continuous railway track fastener assembly in Example 2.

[0030] Explanation of reference numerals in the attached figures

[0031] 1-Support frame; 2-Railway track; 3-Displacement sensor; 4-Acquisition component; 5-Online detection and analysis component; 6-Hollow hydraulic jack; 7-Hollow pressure sensor; 8-Loading platform; 9-Rod shaft; 10-Gantry frame; 11-Spiral rail spike; 12-U-groove; 13-U-shaped support plate; 14-Mounting base. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] In this invention, unless otherwise stated, directional terms such as "up, down, left, right, front, back, inside, outside" in the terminology only represent the orientation of the term in its normal use or are common terms understood by those skilled in the art, and should not be regarded as a limitation on the term.

[0034] See Figure 1 The flowchart shown illustrates the method for calculating the static stiffness of on-site fastener assembly for continuous railway tracks. This method includes the following steps:

[0035] S500, a device for detecting the static stiffness of fastener components;

[0036] S510, load is applied at the center of the rail at the fastener node, and force and displacement information of n fastener nodes is collected;

[0037] S520, establish a mathematical model for continuous long rails and fastener nodes;

[0038] S530, establish the correspondence between the rail loading force and the force at the fastener node;

[0039] S540, perform iterative calculation of the static stiffness of the assembly at the fastener node;

[0040] S550, plot force-displacement curves and stiffness curves;

[0041] The static stiffness testing device for the fastener assembly is configured to be fixed on the railway track 2 and capable of applying a vertical load toward the rail, as well as measuring the vertical displacement of the rail at the fastener node position.

[0042] By implementing the above technical solution, the static stiffness calculation method for the on-site fastener assembly of continuous railway tracks can be used to plot force-displacement curves and stiffness curves, thereby reflecting the assembly status of multiple fasteners in the current continuous line in real time. This improves the current situation of high cost for single-piece and small-batch testing in the laboratory, and the assembly stiffness test results are stable and reliable, avoiding the disadvantages of current laboratory testing such as single-piece testing, high cost, and long time.

[0043] In step S500, the device is moved to the center of the fasteners being tested and locked, so that the loading head is located at the center of the rail, and a load perpendicular to the bottom surface of the rail is applied to the top surface of the rail. Simultaneously, the vertical displacement of the rail is measured using displacement sensor 3.

[0044] In this embodiment, the detection method involves applying force. and Displacement difference and average value measured by lower displacement sensor 3 If the difference is greater than 20%, a repeat test should be conducted, and the test value should not be used.

[0045] Furthermore, the detection method of the present invention can adapt to the temperature and humidity environment on site, has a certain degree of stability, and is adaptable to different site conditions and different types of fasteners.

[0046] In step S510, after calibrating the displacement sensor 3 and the loading device facing the rail, a load is applied to the rail, and at each fastener node, the load is adjusted over time. The changes correspond to different loading forces. Until it is loaded to a fixed value Loading then stops.

[0047] In step S530, the load applied to each fastener node is recorded. and displacement at time and ,in, , ;

[0048] Then, continuous rail loading force is applied. and the actual load force separated to a single fastener The establishment of the mathematical model will apply the force. and The load force transmitted to each fastener node in the continuous track is obtained through calculations performed using the established mathematical model in the analysis component. and ,in, .

[0049] In step S540, based on the calculated loading force and and the displacement of the corresponding nodes. and And obtain an assembly static stiffness according to the stiffness calculation formula. The value is then determined based on the obtained assembly static stiffness. Values ​​and displacements Then, the loading force of the fastener is iterated in reverse through the established continuous track model. This process is repeated, iterating continuously to approach the true reality. Value and value.

[0050] Repeat steps S510-S540 multiple times, pausing for 3-10 seconds after each uninstallation. The loading process continues, and the average value of multiple tests is used as the static stiffness of the fastener assembly. This method makes the calculated data more accurate and valuable for reference.

[0051] In this embodiment, the static stiffness detection device for the fastener assembly includes: a displacement sensor 3, a data acquisition component 4, an online detection and analysis component 5, a support frame 1, and a hydraulic jack installed on the support frame 1 for applying a vertical load to the rail. A loading platform 8 is provided between the hydraulic jack and the rail, and a pressure sensor is provided between the loading platform 8 and the hydraulic jack.

[0052] Two displacement sensors 3 are located on the left and right sides of each fastener node. The displacement value at the corresponding position of the fastener node can be taken as the average value of the two displacement sensors 3. The acquisition component 4 is connected to the displacement sensors 3 and the pressure sensor to collect displacement data and applied pressure values. The online detection and analysis component 5 is used to analyze and calculate the collected data to obtain force-displacement curves and stiffness curves.

[0053] In this embodiment, the hydraulic jack is a hollow hydraulic jack 6, the pressure sensor is a hollow pressure sensor 7, and the loading platform 8 is provided with a rod shaft 9 that can pass through the hollow pressure sensor 7, the hollow hydraulic jack 6, and the support frame 1 in sequence.

[0054] During assembly, the rod shaft 9 is passed through the hollow pressure sensor 7 and the hollow hydraulic jack 6 in sequence. The force exerted by the rail on the loading platform 8 is transmitted to the hollow hydraulic jack 6 after passing through the hollow pressure sensor 7, thus making it easy to measure the magnitude of the loading force.

[0055] In this embodiment, the support frame 1 includes a portal frame 10 and U-shaped support plates 13 disposed at both ends of the portal frame 10. The U-shaped support plates 13 are provided with through holes for installation with spiral rail spikes 11. The portal frame 10 has two structures: one is installed on the sleeper by pre-embedded sleeves pre-embedded in the sleeper, and the other is installed on the original fastener using the spiral rail spikes 11 from the original fastener.

[0056] In this embodiment, the two ends of the portal frame 10 are provided with U-shaped grooves 12 for avoiding the spiral rail spikes 11, and the outer edges of the two ends of the portal frame 10 are provided with mounting seats 14 for installing fastening bolts. The mounting seats 14, U-shaped grooves 12 and spiral rail spikes 11 at the same end are displaced on the same plane. This arrangement makes the support more stable.

[0057] In this embodiment, the mounting holes on the portal frame 10 corresponding to the fastening bolts are configured as elongated holes extending along the length of the parallel rail. The elongated holes allow for fine-tuning of the position during assembly.

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0059] Example 1

[0060] like Figure 3 As shown, the device is installed at the pre-embedded sleeve on the sleeper to detect the static stiffness of the fastener assembly. The real-time displacement of the fastener node can be obtained through displacement sensor 3. However, the force loaded on the upper surface of the rail cannot be fully transmitted to the fastener. Therefore, the correspondence between the rail loading force and the force on the fastener node is determined.

[0061] In railway operations, the forces transmitted from the wheels to the rails can be broadly categorized into vertical forces perpendicular to the rail surface, horizontal forces perpendicular to the rail axis, and longitudinal horizontal forces parallel to the rail axis. Chinese standards employ a continuous supported beam model for simulation calculations of the vertical static force analysis of the rails.

[0062] like Figure 2 As shown, the continuous support beam model considers the sleeper support as a beam continuously supporting the rail, uniformly distributed within the sleeper spacing, with its support stiffness being the elastic modulus of the rail foundation. The vertical load on the rail refers to the vertical dynamic wheel load exerted on the rail by the train wheels during operation. Under a single static wheel load, assuming the rail is a continuous support beam model, the rail is a beam on a continuous elastic support, and the displacement curve under static load is assumed to be... Assuming The reaction force of the foundation under the track at the coordinates and The displacement of the rails is proportional to the deformation of the foundation, which is composed of continuously arranged but independent linear springs. The deformation of each spring depends only on the force acting on it and is independent of the deformation of the adjacent springs.

[0063]

[0064] in, The elastic modulus of the rail. Let be the moment of inertia of the rail section about the horizontal axis.

[0065] Boundary conditions: Under a single load, since the rail is assumed to be infinitely long, the point of application of the load can always be considered as a symmetrical point. Half of the analysis, the boundary conditions are: when The displacement is bounded; at the point of application of the load, the rail rotation angle is 0 ( The sum of the reactions of the foundation under the rail is equal to the rail load. Stress on the fastener nodes:

[0066]

[0067] in: The distance between the rail supports; The elastic coefficient of the rail foundation; For the rail support stiffness; F For wheel load, The elastic modulus of the rail. Let be the moment of inertia of the rail section about the horizontal axis. .

[0068] By establishing the relationship between the loading force and the forces between the fastener nodes, the mathematical model of the rail node in Example 1 was completed. Then, iterative calculations of the fastener assembly stiffness values ​​were performed.

[0069] During the loading of the rail, two loading forces were recorded. and its actual displacement under two loading forces The stiffness of the elastic pad being tested is preset to be... The sleeper pressure is calculated based on the pre-set pad stiffness and the loading force on the rail. And the stiffness under actual displacement is obtained according to the stiffness calculation formula. .

[0070] Set error limits ,when Then let The calculation process is obtained by iterating once. This process is repeated iteratively to solve for the stiffness of the pad. When... Then the current K 2n This is the obtained stiffness value of the elastic pad.

[0071] Based on the iterative calculation process and results, plot the force-displacement curve and the stiffness iteration curve.

[0072] Example 2

[0073] like Figure 4 As shown, the device is installed at the pre-embedded sleeve at the fastener location to test the static stiffness of the fastener assembly. Unlike Example 1, in this case, the fastener assembly at the loading point is completely removed, eliminating its elasticity. Based on the design, the railway rail and fastener model is simplified, resulting in the following mathematical model of the overall design: the fastener at the loading point is disengaged, causing the static stiffness of the assembly at the loading point to disappear. The model can be equivalent to a continuous support beam with springs, and the force at the loading point... F It can be equivalent to the loading force during continuous loading. F This set of fasteners generates an upward elastic force. F 弹 The combined force.

[0074] The continuous support beam model considers the sleeper support as a beam uniformly distributed within the sleeper spacing, continuously supporting the rail. Its support stiffness is the elastic modulus of the rail foundation. The vertical load on the rail refers to the vertical dynamic wheel load exerted on the rail by the train wheels during operation. Under a single static wheel load, assuming the rail is a continuous support beam model, the rail is a beam on a continuous elastic support, and the displacement curve under static load is assumed to be... Assuming The reaction force of the foundation under the track at the coordinates and The displacement of the rails is proportional to the deformation of the foundation, which is composed of continuously arranged but independent linear springs. The deformation of each spring depends only on the force acting on it and is independent of the deformation of the adjacent springs.

[0075]

[0076] in, The elastic modulus of the rail. Let be the moment of inertia of the rail section about the horizontal axis.

[0077] Boundary conditions: Under a single load, since the rail is assumed to be infinitely long, the point of application of the load can always be considered as a symmetrical point. Half of the analysis, the boundary conditions are: when The displacement is bounded; at the point of application of the load, the rail rotation angle is 0 ( The total reaction force of the foundation under the rail is equal to the rail load. Stress on the fastener joint:

[0078]

[0079] in: The distance between the rail supports; The elastic coefficient of the rail foundation; For the rail support stiffness; F For wheel load, The elastic modulus of the rail. Let be the moment of inertia of the rail section about the horizontal axis. .

[0080] By establishing the relationship between the loading force and the forces between the fastener nodes, the mathematical model of the rail node in Example 1 was completed. Then, iterative calculations of the fastener assembly stiffness values ​​were performed.

[0081] The iterative process for calculating the stiffness value of the fastener elastic pad is shown in the flowchart. During the loading of the rail, two loading forces are recorded. and its actual displacement under two loading forces The stiffness of the elastic pad being tested is preset to be... The sleeper pressure is calculated based on the pre-set pad stiffness and the loading force on the rail. And the stiffness under actual displacement is obtained according to the stiffness calculation formula. .

[0082] Set error limits ,when Then let The calculation process is obtained by iterating once. This process is repeated iteratively to solve for the stiffness of the pad. When... Then the current This is the obtained stiffness value of the elastic pad.

[0083] Based on the iterative calculation process and results, plot the force-displacement curve and the stiffness iteration curve.

[0084] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0086] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for calculating the static stiffness of continuous railway track fastener assembly on site, characterized in that, The method for calculating the static stiffness of continuous railway track fastener assembly on site includes the following steps: S500, a device for detecting the static stiffness of fastener components; S510, load is applied at the center of the rail at the fastener node, and force and displacement information of n fastener nodes is collected; S520, establish a mathematical model for continuous long rails and fastener nodes; S530, establish the correspondence between the rail loading force and the force at the fastener node; S540, perform iterative calculation of the static stiffness of the assembly at the fastener node; S550, plot force-displacement curves and stiffness curves; The fastener assembly static stiffness testing device is configured to be fixed on the railway track (2) and capable of applying a vertical load toward the rail, and capable of measuring the vertical displacement of the rail at the fastener node position. In step S510, after calibrating the displacement sensor (3) and the loading device facing the rail, a load is applied to the rail, and at each fastener node, the load is applied over time. The changes correspond to different loading forces. F t and displacement D t Until it is loaded to a fixed value Loading then stops; In step S530, the load applied to each fastener node is recorded. and displacement at time and ,in, , ; Then, continuous rail loading force is applied. and the actual load force separated to a single fastener The establishment of the mathematical model will apply the force. and The load force transmitted to each fastener node in the continuous track is obtained through calculations performed using the established mathematical model in the analysis component. and ,in, ; During the loading of the rail, two loading forces were recorded. and and its actual displacement under two loading forces and The preset stiffness of the fastener node is The stiffness of the pre-set fastener nodes and the force applied on the rail and Calculate the loading force of the fastener node And the stiffness under actual displacement is obtained according to the stiffness calculation formula. ; Set error limits ,when Then let The calculation process is obtained by iterating once. And so on, the stiffness of the fastener nodes is solved iteratively. Then the current K 2n This is the obtained stiffness value of the fastener node; Repeat steps S510-S540 multiple times, pausing for 3-10 seconds after each uninstallation. Continue loading, and use the average value of multiple tests as the static stiffness of the fastener assembly.

2. The method for calculating the static stiffness of continuous railway track fastener assembly on site according to claim 1, characterized in that, The static stiffness detection device for the fastener assembly includes: a displacement sensor (3), a data acquisition component (4), an online detection and analysis component (5), a support frame (1), and a hydraulic jack installed on the support frame (1) for applying a vertical load to the rail. A loading platform (8) is provided between the hydraulic jack and the rail, and a pressure sensor is provided between the loading platform (8) and the hydraulic jack.

3. The method for calculating the static stiffness of continuous railway track fastener assembly on site according to claim 2, characterized in that, The hydraulic jack is a hollow hydraulic jack (6), the pressure sensor is a hollow pressure sensor (7), and the loading platform (8) is provided with a rod shaft (9) that can pass through the hollow pressure sensor (7), the hollow hydraulic jack (6) and the support frame (1) in sequence.

4. The method for calculating the static stiffness of continuous railway track fastener assembly on site according to claim 2, characterized in that, The support frame (1) includes a portal frame (10) and U-shaped support plates (13) disposed at both ends of the portal frame (10). The U-shaped support plates (13) are provided with through holes for installation with spiral rail spikes (11).

5. The method for calculating the static stiffness of continuous railway track on-site fastener assembly according to claim 4, characterized in that, The two ends of the gantry frame (10) are provided with U-shaped grooves (12) for avoiding the spiral spikes (11), and the outer edges of the two ends of the gantry frame (10) are provided with mounting seats (14) for installing fastening bolts. The mounting seats (14), U-shaped grooves (12) and spiral spikes (11) at the same end are located on the same plane.

6. The method for calculating the static stiffness of continuous railway track fastener assembly on site according to claim 5, characterized in that, The mounting holes on the portal frame (10) corresponding to the fastening bolts are set as elongated holes extending along the length of the parallel rail.

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