Method for detecting longitudinal resistance of seamless track under coupling action of temperature and dynamic load

Abstract

The invention provides a method for detecting longitudinal resistance of a continuously welded track under the coupling action of temperature and dynamic load, and relates to the technical field of track traffic, comprising the following steps: acquiring parameter information of the continuously welded track to be detected; constructing a physical model of the to-be-detected seamless track based on the parameter information; carrying out temperature-load collaborative loading and temperature compensation based on the parameter information and the physical model to obtain experimental data in the loading process; constructing a temperature-load-displacement three-dimensional constitutive curved surface based on experimental data; constructing a temperature-load coupling function based on the three-dimensional constitutive curved surface, and calculating the longitudinal resistance of the continuously welded track to be detected through the temperature-load coupling function; and extrapolating the longitudinal resistance of the to-be-detected seamless track to obtain the longitudinal resistance of the similar seamless track. The method solves the problem that an existing seamless track longitudinal resistance detection method cannot comprehensively consider the combined action of double factors of temperature change and train dynamic load.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, and more specifically, to a method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load. Background Technology

[0002] In the field of high-altitude railways, seamless tracks are widely used because they effectively reduce track joints and improve the smoothness of train operation and passenger comfort. However, the unique climatic conditions of high-altitude areas, especially the significant temperature differences and the frequent dynamic loads of trains, pose severe challenges to the stability and safety of seamless tracks. Traditional methods for detecting longitudinal resistance of seamless tracks, such as strain gauge measurement and vibration analysis, have revealed a series of problems when faced with the complex environment of the coupling effect of railway temperature and dynamic loads.

[0003] Existing methods for detecting the longitudinal resistance of seamless railway tracks focus on the single impact of train dynamic loads or changes in ambient temperature on the longitudinal resistance, failing to comprehensively consider the complex situation under the combined effect of temperature changes and train dynamic loads. In actual railway operation, seamless railway tracks are often simultaneously subjected to large fluctuations in ambient temperature and the dynamic loads of frequent train operations. The combined effect of these two factors on the longitudinal resistance of the track is more complex and critical. Summary of the Invention

[0004] The purpose of this invention is to provide a method for detecting the longitudinal resistance of seamless railway tracks under the coupled effects of temperature and dynamic loads, thereby improving the aforementioned problems. To achieve this objective, the technical solution adopted by this invention is as follows:

[0005] Firstly, this application provides a method for detecting the longitudinal resistance of seamless railway tracks under the coupled effects of temperature and dynamic loads, including:

[0006] Obtain parameter information of the seamless line to be inspected;

[0007] A physical model of the seamless line to be detected is constructed based on parameter information;

[0008] Based on parameter information and physical models, temperature-load synergistic loading and temperature compensation are performed to obtain experimental data during the loading process. The experimental data includes temperature, load and rail displacement at each time point.

[0009] A three-dimensional constitutive surface relating temperature, load, and displacement was constructed based on experimental data;

[0010] A temperature-load coupling function is constructed based on a three-dimensional constitutive surface, and the longitudinal resistance of the seamless track to be tested is calculated through the temperature-load coupling function.

[0011] The longitudinal resistance of similar seamless lines is obtained by extrapolating from the longitudinal resistance of the seamless line to be tested.

[0012] The beneficial effects of this invention are as follows: The detection method designed in this invention fully considers the coupling effect of temperature change rate and dynamic load frequency on the longitudinal resistance of seamless railway tracks. By constructing a three-dimensional constitutive surface and a temperature-load coupling function, high-precision modeling of the longitudinal resistance is achieved. The accuracy of detection is improved by introducing a correction factor to compensate for the loading hysteresis effect. Furthermore, this method supports extrapolating the detection results to seamless railway tracks with similar structures and operating conditions, expanding its applicability. Compared with traditional methods, this invention has higher physical consistency and engineering practicality, and is suitable for safety monitoring and maintenance in various seamless railway track scenarios, including high-speed railways and heavy-haul railways.

[0013] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the process for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load, as described in an embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0017] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] Example 1:

[0019] This embodiment provides a method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load.

[0020] See Figure 1 The figure shows that the method includes steps S1, S2, S3, S4, S5 and S6.

[0021] Step S1: Obtain parameter information of the seamless line to be tested;

[0022] In step S1, the step of obtaining the parameter information is as follows:

[0023] Step S11: Obtain the material property parameters of the seamless track to be tested, including rail material parameters, sleeper and fastener parameters, and temperature-related parameters;

[0024] In this embodiment, the rail material parameters include elastic modulus, Poisson's ratio, coefficient of thermal expansion, yield strength, and material density. The sleeper and fastener parameters include fastener stiffness, damping coefficient, elastic modulus of the track material, and ballast friction coefficient. Temperature-related parameters include material thermal conductivity, specific heat capacity, and thermal softening coefficient.

[0025] Step S12: Obtain the geometric structure parameters of the seamless line to be inspected, including the line geometric parameters and fastener arrangement parameters;

[0026] In this embodiment, the track geometry parameters include sleeper spacing, rail cross-sectional dimensions, and track curvature radius. Fastener arrangement parameters include fastener spacing, fastening force, and spring clip type.

[0027] Step S13: Obtain the environmental and load parameters of the seamless line to be tested, including the actual temperature range and actual dynamic load of the seamless line to be tested.

[0028] In this embodiment, the actual temperature range is the temperature of the environment where the seamless track to be tested is located, for example, -30℃ to +40℃. The actual dynamic load is the real, changing dynamic load that the track structure experiences during normal operation of the seamless track, usually caused by train operation.

[0029] Step S14: Use material property parameters, geometric parameters, and environmental and load parameters as parameter information for the seamless line to be tested.

[0030] Step S2: Construct a physical model of the seamless line to be detected based on the parameter information;

[0031] Step S3: Based on parameter information and physical model, perform temperature-load coordinated loading and temperature compensation to obtain experimental data during the loading process. The experimental data includes temperature, load and rail displacement at each time point.

[0032] Step S3 includes:

[0033] Step S31: Obtain the actual temperature range and actual dynamic load based on the parameter information;

[0034] Step S32: Design a temperature cyclic loading scheme and a dynamic load time-varying scheme based on the actual temperature range and the actual dynamic load. The temperature cyclic loading scheme includes the temperature change rate, and the dynamic load time-varying scheme includes the load frequency.

[0035] In this embodiment, the temperature range covering the normal operating temperature of the circuit under different environmental conditions needs to be precisely set according to the experimental requirements and the material properties of the seamless circuit, in order to ensure the comprehensiveness and accuracy of the experiment. For example, it is designed to perform multiple cycles of temperature loading and load loading (simulating day and night) over 12 hours, such as dynamic continuous temperature loading at a temperature change rate of ±5℃ / h within the range of -30℃ to +40℃, and dynamic load is applied simultaneously.

[0036] Step S33: Construct the temperature loading function and the dynamic load loading function based on the temperature cyclic loading scheme and the dynamic load time-varying scheme;

[0037] In this embodiment, parameters such as the magnitude, frequency, and waveform of the load need to be precisely set according to experimental requirements. These parameters must fully consider the actual working conditions and possible extreme situations of the seamless circuit. A load generator can be used to generate dynamic loads from the preset load parameters and apply them to the physical model of the seamless circuit.

[0038] The waveform of the dynamic load can be set to various waveforms such as sine wave, square wave, and triangular wave according to experimental requirements to meet the simulation needs under different conditions. To more comprehensively simulate the dynamic load characteristics under actual conditions, multiple loads of different frequencies can be combined and applied. Therefore, a time-dependent dynamic load loading function can be constructed, and its waveform can be set to sine wave, square wave, etc., according to experimental requirements. For example, the dynamic load loading function as a sine wave load can be expressed as:

[0039]

[0040] In the formula, F(t) represents the sinusoidal load with respect to time t, F0 represents the load amplitude of the sinusoidal load, and ω represents the load frequency. Indicates the initial phase.

[0041] Step S34: Perform temperature-load synergistic loading and temperature compensation on the physical model using the temperature loading function and dynamic load loading function, and obtain experimental data during the loading process.

[0042] In step S34, the coordinated loading and temperature compensation of temperature and load includes:

[0043] Step A1: Calculate the required loading temperature and load at each moment using the temperature loading function and the dynamic load loading function;

[0044] Step A2: Apply the corresponding loading temperature and load to the physical model at each time step;

[0045] In this embodiment, during temperature loading, environmental simulation devices such as heating lamps and cooling fans are used to simulate the impact of natural factors such as sunlight and temperature changes on the track temperature, thereby simulating temperature variations under different seasons and weather conditions. Once the environmental change simulation begins, a high-precision temperature control system, including heating / cooling elements, temperature sensors, and a controller, is immediately activated. The temperature sensors monitor the temperature of the seamless track in real time and feed the data back to the controller. The controller then adjusts the heating / cooling power based on a built-in PID control algorithm and the temperature error (the difference between the target temperature and the actual temperature). This adjustment continues until the temperature reaches the target temperature and remains stable. Simultaneously, temperature changes are continuously monitored and fine-tuned to ensure the accuracy and stability of temperature control. The target temperature is the calculated loading temperature.

[0046] The temperature control algorithm can use the PID control algorithm, and its formula is:

[0047]

[0048] In the formula, u(t) represents the output power at time t, e(t) represents the temperature error at time t, and K p K i and K d Both represent control coefficients, and e(τ) represents the temperature error at time τ.

[0049] The PID control algorithm, through the adjustment of three parameters—proportional (P), integral (I), and derivative (D)—achieves precise temperature control, ensuring that the temperature of the seamless circuit is accurately controlled within the target range. Furthermore, the controller can quickly adjust the output power of the heating or cooling equipment based on the deviation between the current temperature and the set temperature, thus responding rapidly to temperature changes. Integral control eliminates steady-state errors, and derivative control anticipates and suppresses temperature change trends. The PID algorithm ensures that the temperature remains stable after reaching the target range, avoiding excessive fluctuations.

[0050] During dynamic load application, a load generator applies the load calculated by the dynamic load application function to the physical model of the seamless track. Load sensors monitor the magnitude of the load applied to the track in real time and feed the data back to the control system. The control system then dynamically adjusts the output of the load generator using a PID algorithm to ensure that the actual applied load force value (including load amplitude, load frequency, and waveform) is consistent with the parameters in the dynamic load application function, with the error controlled within ±2%.

[0051] Step A3: Obtain the rail displacement and applied load at each moment during the loading process;

[0052] Step A4: If the rail displacement exceeds the preset displacement, then expand the loading temperature range.

[0053] In this embodiment, when the rail displacement exceeds the theoretical value by 15%, the material has entered the nonlinear response stage (such as plastic deformation or microcrack propagation). At this point, the loading temperature range is extended (e.g., adjusted from -30℃ to +40℃ to -35℃ to +45℃). The purpose of this extension is to facilitate the identification of material phase transition points. For example, some rail alloys undergo a ductile-brittle transition at extreme low temperatures (e.g., -35℃), leading to a sharp drop in resistance. Extension can reveal interface failure mechanisms; for example, at high temperatures (e.g., 45℃), the friction coefficient at the ballast-sleeper interface decreases by 40% to 60% due to softening of the asphalt pad. Extension also facilitates the establishment of subsequent safety thresholds, determining the resistance attenuation inflection point through over-limit tests, and providing early warning thresholds for actual line maintenance (e.g., emergency intervention is required if displacement exceeds 8mm).

[0054] Step A5: If the applied load exceeds the preset load, temperature compensation is performed to increase the rate of temperature change and recalculate the required loading temperature. The recalculated loading temperature is then applied to the physical model.

[0055] In this embodiment, the essence of the load coupling requirement actually refers to the intensity of the interaction between mechanical vibration and temperature change. At higher load frequencies (typically exceeding 25Hz), the fretting friction at the contact surface caused by mechanical vibration significantly increases, leading to fluctuations in electrical contact resistance of 15%–25%, thus affecting the uniformity of eddy current heating and the stability of temperature control. According to the energy conservation relationship of thermo-mechanical coupling, higher frequencies require the system to have a faster temperature rise response to maintain thermo-mechanical coupling balance. Therefore, the control system under high-frequency dynamic loads must meet the coupling requirements of temperature response and vibration frequency to avoid data distortion or model deviation.

[0056] In this step, when the load frequency is >25Hz (simulating dense train passage), temperature compensation is performed, that is, the temperature change rate is increased synchronously (±10℃ / h).

[0057] Temperature compensation can reproduce the heat accumulation effect. High-frequency loads lead to heat accumulation due to wheel-rail friction. Actual measurements show that when 30 trains pass every 10 minutes, the rail temperature can rise by up to 12°C. It can also match the thermo-mechanical coupling timescale; rapid temperature change (10°C / h) synchronizes the material's heat conduction with the mechanical response of high-frequency loads, avoiding the thermal hysteresis distortion caused by traditional slow temperature change (5°C / h). Simultaneously, it can stimulate dynamic recrystallization. Under high-temperature rapid cycling, the grain boundary sliding rate of the rail increases, and a critical phenomenon of a 20%–30% decrease in resistance can be observed.

[0058] In step S34, the steps for obtaining the experimental data are as follows:

[0059] Step B1: Obtain the loading temperature and load at each moment during the loading process, as the temperature and load at the corresponding time point;

[0060] Step B2: Obtain images of the physical model at each moment during the loading process;

[0061] Step B3: Extract feature points from each image using an image recognition algorithm. These feature points represent the locations of rail deformation on the physical model.

[0062] Step B4: Obtain the location of feature points in each image;

[0063] Step B5: By spatially transforming the position of the feature point in each image with the initial position, calculate the rail displacement at each time point during the loading process with respect to the initial position, where the initial position is the position of the feature point before loading.

[0064] In this embodiment, the formula for spatial transformation is:

[0065]

[0066] In the formula, Δx and Δy represent the actual displacement of the feature point in the x and y directions, respectively; x1 and x2 represent the abscissas of the feature point before and after loading, respectively; y1 and y2 represent the ordinates of the feature point before and after loading, respectively; and d... pixel f' represents the camera's pixel size, f' represents the camera's focal length, and D represents the shooting distance from the camera to the physical model.

[0067] Step S4: Construct a three-dimensional constitutive surface relating temperature, load, and displacement based on experimental data;

[0068] In this embodiment, a three-dimensional constitutive relationship between temperature, load, and displacement is constructed based on experimental data, that is, the nonlinear response characteristics of the rail under thermo-mechanical coupling are characterized by a three-dimensional constitutive surface.

[0069] In step S4, the construction steps of the three-dimensional constitutive surface are as follows:

[0070] Step S41: Take the average value of the rail displacement at different time points under the same temperature and load to obtain the average displacement value;

[0071] In this embodiment, experimental data is obtained through dense sampling (e.g., at 0.5°C intervals). The average value of rail displacement at multiple time points under the same temperature and load in the experimental data is obtained.

[0072] Step S42: Construct multiple sparse sampling points based on the average values ​​of temperature, load, and displacement;

[0073] Step S43: Divide all sparse sampling points according to whether temperature compensation is performed, to obtain uncompensated sampling points and compensated sampling points;

[0074] In this embodiment, the classification is based on whether temperature compensation is performed, i.e., by the load magnitude. Sparse sampling points with a frequency greater than 25Hz are classified as compensated sampling points. Compensated sampling points indicate significant eddy current heating compensation behavior, requiring modeling of hysteresis effects.

[0075] Step S44: Perform interpolation and fitting operations based on the uncompensated sampling points to obtain an initial three-dimensional function of temperature-load-displacement;

[0076] In this embodiment, interpolation and fitting operations (such as polynomial fitting, spline interpolation, Kriging interpolation, etc.) are used to model the uncompensated sampling points to obtain an initial three-dimensional function. The initial three-dimensional function is the ideal response under the condition of no thermo-mechanical hysteresis compensation.

[0077] Step S45: Construct a correction factor to compensate for the lag effect based on the compensated sampling points;

[0078] In this embodiment, the displacement response deviation caused by coupling effects such as eddy current heating under high-frequency dynamic load is corrected by a correction factor.

[0079] In step S45, the construction step of the correction factor is as follows:

[0080] Step S451: Input the temperature and load of each compensated sampling point into the initial three-dimensional function to obtain the corresponding displacement prediction value;

[0081] Step S452: Calculate the difference between each predicted displacement value and the mean displacement value in the corresponding compensated sampling points to obtain the corresponding displacement correction amount;

[0082] Step S453: Perform interpolation and fitting operations on the temperature, load, and corresponding displacement corrections to obtain correction factors related to the load frequency and temperature change rate.

[0083] Step S46: Construct a three-dimensional constitutive surface about temperature-load-displacement based on the initial three-dimensional function and correction factor.

[0084] In this embodiment, the obtained three-dimensional constitutive surface with respect to temperature-load-displacement is ΔX=f(T,F,ω,ΔT), where ΔX represents the rail displacement, f(T,F,ω,ΔT) represents the three-dimensional function with respect to T, F, ω and ΔT, T represents temperature, F represents load, ω represents load frequency, and ΔT represents the rate of temperature change, i.e. temperature gradient.

[0085] And f(T,F,ω,ΔT)=f′(T,F)+η(ω,ΔT), where f′(T,F) represents the initial three-dimensional function with respect to T and F, and η(ω,ΔT) represents the correction factor with respect to ω and ΔT.

[0086] Therefore, by embedding the time variable into the fitting process of the three-dimensional constitutive surface (temperature-load-displacement), the three-dimensional constitutive surface is generated by interpolation based on densely sampled data. Its essence is to reflect the influence of the time dimension through parametric mapping (load frequency ω, temperature change rate ΔT). By establishing a correction factor, it is not necessary to construct an explicit four-dimensional surface. The correction factor compensates for the hysteresis effect, ensuring that the three-dimensional constitutive surface represents the longitudinal resistance evolution law under continuous time-varying working conditions.

[0087] Step S5: Construct a temperature-load coupling function based on the three-dimensional constitutive surface, and calculate the longitudinal resistance of the seamless track to be tested through the temperature-load coupling function;

[0088] In this embodiment, a temperature-load coupling function is constructed by combining the constitutive equations of mechanics of materials (such as the nonlinear relationship between displacement and resistance) and a three-dimensional constitutive surface. The longitudinal resistance of a seamless track under any temperature and load can be directly calculated through the temperature-load coupling function.

[0089] In step S5, the construction of the temperature-load coupling function based on the three-dimensional constitutive surface includes:

[0090] Step S51: Based on the nonlinear relationship between displacement and resistance in mechanics of materials, construct the displacement-resistance function;

[0091] In this embodiment, the displacement-resistance function adopts the classical elastoplastic constitutive relation, namely Hooke's law, specifically:

[0092] R = KΔX

[0093] In the formula, R represents longitudinal resistance, K represents longitudinal stiffness coefficient, and ΔX represents rail displacement.

[0094] Step S52: Input the rail displacement in the three-dimensional constitutive surface into the displacement-resistance function for calculation to obtain the corresponding longitudinal resistance, and construct a dataset related to temperature, load, load frequency, temperature change rate and corresponding longitudinal resistance.

[0095] Step S53: Perform multivariate fitting using the dataset, with temperature, load, load frequency and temperature change rate as input variables and longitudinal resistance as output variable, to obtain the temperature-load coupling function.

[0096] In this embodiment, the dynamic mapping between rail displacement and longitudinal resistance is realized by fitting the function expression based on multiple regression analysis or machine learning algorithm (such as neural network), and the temperature-load coupling function R = f(F, ΔT, T, ω) is obtained. The temperature-load coupling function is used for quantitative correlation, where R represents longitudinal resistance, T represents temperature, F represents load, ω represents load frequency, and ΔT represents temperature change rate, i.e. temperature gradient.

[0097] Step S6: Extrapolate the longitudinal resistance of the seamless line to be tested to obtain the longitudinal resistance of similar seamless lines.

[0098] Step S6 includes:

[0099] Step S61: Calculate the scaling factor using the elastic modulus of the track material and the sleeper spacing of the seamless track to be tested and similar seamless tracks;

[0100] In this embodiment, since the longitudinal resistance of the seamless line to be tested has been calculated using the temperature-load coupling function, the seamless line to be tested is taken as the known reference line, and the similar seamless line is taken as the new line to be solved. The similar seamless line has been determined as the similar line of the reference line.

[0101] The formula for the scaling factor is:

[0102]

[0103] In the formula, λ represents the scaling factor, and E 新 and E 基 L represents the elastic modulus of the track material for similar seamless tracks and reference tracks, respectively. 新 and L 基 These represent the sleeper spacing of similar seamless tracks and the reference track, respectively.

[0104] Step S62: Construct a temperature-load coupling function for a similar seamless circuit by using a scaling factor and the temperature-load coupling function of the seamless circuit to be detected;

[0105] In this embodiment, the longitudinal resistance calculation formula of the reference line is mapped to the new line using a scaling factor, specifically as follows:

[0106] R 新 =λ·R 基

[0107] In the formula, R 新 R represents the longitudinal resistance of a similar seamless track, λ represents the scaling factor, and R 基 The longitudinal resistance of the reference line is calculated using the temperature-load coupling function of the reference line.

[0108] Step S63: Calculate the longitudinal resistance of the similar seamless track using the temperature-load coupling function of the similar seamless track.

[0109] In step S6, the determination step for similar seamless lines is as follows:

[0110] Step C1: Obtain the dimensional analysis parameters of the seamless track to be tested and the target seamless track. The dimensional analysis includes load amplitude, elastic modulus of track material, sleeper spacing, load frequency and material density.

[0111] Step C2: Calculate the dimensionless parameters of the seamless circuit to be tested and the target seamless circuit based on the dimensional analysis parameters;

[0112] In this embodiment, the dimensionless parameter includes a first dimensionless parameter and a second dimensionless parameter. The calculation formula for the dimensionless parameter is as follows:

[0113]

[0114] In the formula, π1 represents the first dimensionless parameter, π2 represents the second dimensionless parameter, F′ represents the load amplitude, E represents the elastic modulus of the track material, L represents the sleeper spacing, ρ represents the material density, and ω represents the load frequency.

[0115] The first and second dimensionless parameters of the seamless circuit to be detected, as well as the first and second dimensionless parameters of the target seamless circuit, are calculated using the formula for calculating dimensionless parameters.

[0116] Step C3: Determine whether the similarity criterion is met based on the dimensionless parameter. If so, the target seamless line is a similar seamless line to the seamless line to be detected.

[0117] In this embodiment, if the absolute difference between the first dimensionless parameter of the seamless line to be detected and the target seamless line is less than 0.15, and the absolute difference between the second dimensionless parameter of the seamless line to be detected and the target seamless line is less than 0.15, then the target seamless line can be used as a similar seamless line to the seamless line to be detected, that is, the temperature-load coupling function of the seamless line to be detected is extrapolated to the similar seamless line for use.

[0118] This is because the relationship between temperature, dynamic load and longitudinal resistance varies among different seamless tracks, but this can be mitigated by extrapolating to reduce repeated testing and mapping the relationship.

[0119] Example 2:

[0120] In this embodiment, a cross-scale extrapolation application is presented. Specifically, the information of the baseline line is: 60kg / m rail, E 基 =210GPa, L 基 =0.6m. Through the temperature-load coupling function of the reference line, the longitudinal resistance of the reference line is 12kN / m when the temperature is 40℃, the load amplitude is 50kN, and the load frequency is 2Hz.

[0121] The new line information is: 75kg / m rail, E 新 =200GPa, L 新 =0.7m, the longitudinal resistance needs to be calculated when the temperature is 40℃, the load amplitude is 60kN, and the load frequency is 1.8Hz.

[0122] Based on the above information, a similarity verification was performed to determine whether the similarity criteria were met. Calculations showed that the first dimensionless parameter of the baseline and the new line were 6.61 × 10⁻⁶. -7 and 6.12×10 -7 The second dimensionless parameters of the baseline and the new line are 0.021 and 0.019, respectively.

[0123] When performing similarity verification, |6.61×10 -7 -6.12×10 -7 |=0.49×10 -7Since |0.021-0.019| = 0.002, both of which are less than 0.15, the new line is a similar line to the baseline line and can be extrapolated for longitudinal resistance.

[0124] Therefore, the scaling factor λ is calculated to be 1.30, and the longitudinal resistance of the new line at a temperature of 40℃, a load amplitude of 60kN, and a load frequency of 1.8Hz is 15.6kN / m.

[0125] Verification showed that the actual test result of the new line at a temperature of 40℃, a load amplitude of 60kN, and a load frequency of 1.8Hz was 16.1kN / m, with an error of only 3.1%.

[0126] In summary, the method designed in this invention comprehensively considers the coupled effects of temperature change rate and load frequency on rail displacement and longitudinal resistance. By constructing a three-dimensional constitutive surface and a temperature-load coupling function, high-precision modeling and evaluation of the longitudinal resistance of seamless tracks under real operating conditions are achieved. Simultaneously, the method of extracting rail displacement using image recognition and constructing a correction factor effectively compensates for the loading hysteresis effect, improving the accuracy and robustness of data processing.

[0127] Furthermore, this method acquires data through experiments using a physical model and introduces similarity criteria and scaling strategies, enabling the extrapolation of detection results to similar lines under different structures and operating conditions, significantly expanding the applicability of the detection method. Compared to traditional detection methods that rely on field tests or simplified assumptions, this invention has stronger physical consistency and engineering adaptability, making it suitable for seamless line condition assessment and safe operation and maintenance in various typical operating scenarios such as high-speed railways and heavy-haul railways.

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0129] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for detecting the longitudinal resistance of seamless railway tracks under the coupled effects of temperature and dynamic load, characterized in that, include: Obtain parameter information of the seamless line to be tested; A physical model of the seamless line to be detected is constructed based on parameter information; Based on parameter information and physical models, temperature-load synergistic loading and temperature compensation are performed to obtain experimental data during the loading process. The experimental data includes temperature, load and rail displacement at each time point. A three-dimensional constitutive surface relating temperature, load, and displacement was constructed based on experimental data; A temperature-load coupling function is constructed based on a three-dimensional constitutive surface, and the longitudinal resistance of the seamless track to be tested is calculated through the temperature-load coupling function. The longitudinal resistance of similar seamless lines is obtained by extrapolating from the longitudinal resistance of the seamless line to be tested.

2. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 1, characterized in that... The steps for obtaining the parameter information are as follows: Obtain the material property parameters of the seamless track to be inspected, including rail material parameters, sleeper and fastener parameters, and temperature-related parameters; Obtain the geometric structure parameters of the seamless line to be inspected, including the line geometric parameters and fastener arrangement parameters; Obtain the environmental and load parameters of the seamless line to be tested, including the actual temperature range and actual dynamic load of the seamless line to be tested. Material property parameters, geometric parameters, and environmental and load parameters are used as parameter information for the seamless line to be tested.

3. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 1, characterized in that... The temperature-load synergistic loading and temperature compensation based on parameter information and physical model yields experimental data during the loading process, including: Obtain the actual temperature range and actual dynamic load based on the parameter information; Based on the actual temperature range and the actual dynamic load, design a temperature cyclic loading scheme and a dynamic load time-varying scheme. The temperature cyclic loading scheme includes the temperature change rate, and the dynamic load time-varying scheme includes the load frequency. Construct temperature loading functions and dynamic load loading functions based on temperature cyclic loading scheme and dynamic load time-varying scheme; The physical model was subjected to coordinated temperature-load loading and temperature compensation using temperature loading functions and dynamic load loading functions, and experimental data were obtained during the loading process.

4. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 3, characterized in that... The aforementioned temperature-load coordinated loading and temperature compensation includes: The required loading temperature and load at each moment are calculated using the temperature loading function and the dynamic load loading function. At each moment, the physical model is subjected to the corresponding loading temperature and load. Obtain the rail displacement and applied load at each moment during the loading process; If the rail displacement exceeds the preset displacement, the loading temperature range will be expanded. If the applied load exceeds the preset load, temperature compensation is performed to increase the rate of temperature change and recalculate the required loading temperature. The recalculated loading temperature is then applied to the physical model.

5. The method for detecting the longitudinal resistance of seamless tracks under the coupled action of temperature and dynamic load as described in claim 4, characterized in that... The steps for obtaining the experimental data are as follows: The loading temperature and load at each moment during the loading process are obtained and used as the temperature and load at the corresponding time points. Get images of the physical model at each moment during the loading process; Feature points are extracted from each image using an image recognition algorithm. These feature points represent the locations of rail deformation on the physical model. Obtain the location of feature points in each image; By spatially transforming the position of feature points in each image with the initial position, the rail displacement at each time point during the loading process with respect to the initial position is calculated. The initial position is the position of the feature points when no loading is applied.

6. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 1, characterized in that... The steps for constructing the three-dimensional constitutive surface are as follows: The average displacement value is obtained by taking the average value of the rail displacement at different time points under the same temperature and load. Multiple sparse sampling points are constructed based on the average values ​​of temperature, load, and displacement; All sparse sampling points are divided into uncompensated sampling points and compensated sampling points according to whether temperature compensation is performed. Interpolation and fitting operations are performed based on uncompensated sampling points to obtain an initial three-dimensional function of temperature-load-displacement; A correction factor for compensating for lag effects is constructed based on the compensated sampling points; A three-dimensional constitutive surface relating temperature, load, and displacement is constructed based on the initial three-dimensional function and the correction factor.

7. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 6, characterized in that... The steps for constructing the correction factor are as follows: The temperature and load at each compensated sampling point are input into the initial three-dimensional function to obtain the corresponding displacement prediction value; The corresponding displacement correction amount is obtained by calculating the difference between each predicted displacement value and the mean displacement value in the corresponding compensated sampling points. Interpolation and fitting operations are performed on temperature, load, and corresponding displacement corrections to obtain correction factors related to load frequency and temperature change rate.

8. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 1, characterized in that... The construction of the temperature-load coupling function based on the three-dimensional constitutive surface includes: Based on the nonlinear relationship between displacement and resistance in mechanics of materials, a displacement-resistance function is constructed. The rail displacement in the three-dimensional constitutive surface is input into the displacement-resistance function for calculation to obtain the corresponding longitudinal resistance, and a dataset related to temperature, load, load frequency, temperature change rate and corresponding longitudinal resistance is constructed. Multivariate fitting was performed on the dataset, with temperature, load, load frequency and temperature change rate as input variables and longitudinal drag as output variable, to obtain the temperature-load coupling function.

9. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 1, characterized in that... The extrapolation of the longitudinal resistance of the seamless track to be tested to obtain the longitudinal resistance of similar seamless tracks includes: The scaling factor is calculated based on the elastic modulus of the track material and the sleeper spacing of the seamless track to be tested and similar seamless tracks. By using a scaling factor and the temperature-load coupling function of the seamless line to be detected, a temperature-load coupling function for a similar seamless line is constructed. The longitudinal resistance of a similar seamless track is calculated using a temperature-load coupling function.

10. The method for detecting the longitudinal resistance of seamless tracks under the coupled effects of temperature and dynamic load as described in claim 1, characterized in that... The steps for determining similar seamless lines are as follows: Obtain dimensional analysis parameters for the seamless track to be tested and the target seamless track. The dimensional analysis includes load amplitude, elastic modulus of track material, sleeper spacing, load frequency, and material density. Calculate the dimensionless parameters of the seamless line to be detected and the target seamless line based on the dimensional analysis parameters. The similarity criterion is determined based on the dimensionless parameter. If it is, the target seamless line is a similar seamless line to the seamless line to be detected.

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