Methods, systems, devices, equipment and media for assessing axial force in air supply duct connection systems

Abstract

This invention discloses a method, system, device, equipment, and medium for assessing the axial force of an air supply duct connection system. It applies to the field of axial force assessment technology for duct connection systems, specifically to the air supply duct connection system of a train. The air supply duct connection system includes a pipe, a pipe fitting, and a nut. The pipe and pipe fitting are sealed together by a flared conical surface fit structure. The nut is threadedly connected to the pipe fitting to ensure tight contact between the pipe and the pipe fitting. The axial force assessment method for the air supply duct connection system includes: acquiring real-time axial force data of the nut during train operation; determining, based on the real-time axial force data, whether the real-time axial force of the nut remains less than a first preset threshold for a first preset time; if so, triggering a first-level warning. When the real-time axial force remains less than the first preset threshold for a first preset time, it indicates a risk of leakage, triggering a first-level warning, thus achieving online safety assessment of the sealing performance of the air supply duct connection system to reduce sudden leakage failures.

Description

Technical Field

[0001] This invention relates to the field of axial force assessment technology for pipeline connection systems, and more specifically, to a method, system, device, equipment, and medium for assessing axial force in air supply pipeline connection systems. Background Technology

[0002] The air supply pipelines of rail vehicles are mainly used to transport compressed air, and the sealing performance of the air supply pipeline connection system is directly related to the driving safety. At present, the pipes of the air supply pipeline connection system are made of stainless steel or carbon steel pipes, and the sealing performance of stainless steel or carbon steel pipe connections has been verified in the operation of rail vehicles (such as EMU trains) for many years.

[0003] However, with the increasing demand for lightweight rail vehicles, aluminum alloy pipes and fittings have begun to be introduced into air supply duct connection systems. Unlike the sealing structure of stainless steel pipes, aluminum alloy pipes use a flared conical surface fit structure to achieve a tight seal at the pipe connection. The axial force generated by tightening the nut and pipe fitting threads ensures a tight seal between the pipe and the flared conical surface fit structure. In other words, the axial force of the nut is a key indicator for achieving an effective seal in the air supply duct connection system.

[0004] However, in the relevant technologies, during the assembly of the air supply pipeline connection system, the nuts are simply tightened according to a certain torque value, without any subsequent axial force monitoring measures.

[0005] During long-term operation of rail vehicles, the connection parts of the air supply pipeline connection system are affected by multiple factors such as vibration, impact, temperature changes and airflow pulsation, which can easily lead to loose nuts, resulting in a decrease in the sealing performance of the air supply pipeline connection system. In severe cases, it can even lead to air leakage, affecting the operational safety of rail vehicles.

[0006] Therefore, how to evaluate the sealing performance of the air supply pipeline connection system based on axial force is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a method for evaluating the axial force of an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on the axial force.

[0008] Another objective of this invention is to provide an axial force evaluation system for an air supply duct connection system, which implements the aforementioned axial force evaluation method for an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on the axial force.

[0009] Another object of the present invention is to provide an axial force evaluation device for an air supply duct connection system, corresponding to the above-mentioned axial force evaluation method for an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on axial force.

[0010] Another object of the present invention is to provide an axial force evaluation device for an air supply duct connection system, corresponding to the above-mentioned axial force evaluation method for an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on axial force.

[0011] Another object of the present invention is to provide a computer-readable storage medium corresponding to the above-described method for evaluating the axial force of an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on the axial force.

[0012] To achieve the above objectives, the present invention provides the following technical solution:

[0013] An axial force evaluation method for an air supply pipeline connection system is applied to the air supply pipeline connection system of a train. The air supply pipeline connection system includes a pipe, a pipe joint, and a nut. The pipe and the pipe joint are sealed and abutted by a flared conical surface mating structure. The nut is threadedly connected to the pipe joint so that the pipe and the pipe joint are tightly abutted.

[0014] The method for evaluating the axial force of the air supply duct connection system includes:

[0015] Acquire real-time axial force data of the nut during train operation;

[0016] Based on the real-time axial force data, determine whether the real-time axial force of the nut has been less than a first preset threshold for a first preset time.

[0017] If so, a Level 1 warning will be triggered.

[0018] Optionally, after determining whether the real-time axial force of the nut has remained below a first preset threshold for a first preset time, the method further includes:

[0019] If the real-time axial force of the nut continues for a period of time that is not less than the first preset threshold, the axial force attenuation rate of the nut is obtained based on the real-time axial force data.

[0020] Determine whether the axial force attenuation rate continues for a second preset time greater than a second preset threshold;

[0021] If so, a Level 2 warning will be triggered.

[0022] Optionally, after acquiring the real-time axial force data of the nut during train operation, the method further includes:

[0023] Based on the real-time axial force data, the axial force fluctuation amplitude and axial force fluctuation frequency of the nut are obtained;

[0024] Obtain the pipeline pressure data of the air supply pipeline connection system, and calculate the pipeline pressure fluctuation frequency based on the pipeline pressure data;

[0025] Determine whether the amplitude of the axial force fluctuation is greater than a third preset threshold, and determine whether the frequency of the axial force fluctuation matches the frequency of the pipeline pressure fluctuation;

[0026] If the amplitude of the axial force fluctuation is greater than the third preset threshold, and the frequency of the axial force fluctuation matches the frequency of the pipeline pressure fluctuation, an emergency warning is triggered.

[0027] Optionally, after determining whether the real-time axial force of the nut has remained below a first preset threshold for a first preset time, the method further includes:

[0028] If the real-time axial force of the nut is maintained for less than the first preset time, the pipeline pressure fluctuation amplitude of the air supply pipeline connection system and the vibration acceleration of the nut are obtained.

[0029] Calculate the first correlation coefficient between the real-time axial force, the pipeline pressure fluctuation amplitude, and the vibration acceleration;

[0030] Determine whether the first correlation coefficient is greater than or equal to the fourth preset threshold;

[0031] If so, trigger the Level 1 warning.

[0032] Optionally, after determining whether the axial force attenuation rate continues for a second preset time greater than a second preset threshold, the method further includes:

[0033] If the axial force attenuation rate continues for a period of time longer than the second preset threshold, the pipeline pressure fluctuation amplitude of the train's air supply pipeline is obtained.

[0034] Calculate the second correlation coefficient between the axial force attenuation rate and the pipeline pressure fluctuation amplitude;

[0035] Determine whether the second correlation coefficient is greater than or equal to the fifth preset threshold;

[0036] If so, the level 2 warning will be triggered.

[0037] Optionally, after determining whether the axial force fluctuation amplitude is greater than a third preset threshold and whether the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency, the method further includes:

[0038] If the amplitude of the axial force fluctuation is greater than the third preset threshold, and the frequency of the axial force fluctuation matches the frequency of the pipeline pressure fluctuation, the vibration peak frequency of the pipeline connection system is obtained.

[0039] Calculate the third correlation coefficient between the axial force fluctuation frequency and the vibration peak frequency;

[0040] Determine whether the third correlation coefficient is greater than or equal to the sixth preset threshold;

[0041] If so, the aforementioned emergency warning will be triggered.

[0042] Optionally, real-time axial force data of the nut during train operation is obtained, including:

[0043] When the measured sound detected by the ultrasonic sensor installed at one end of the nut is obtained, the ultrasonic sensor generates ultrasonic waves using the piezoelectric effect, and the measured sound time is the time it takes for the ultrasonic wave detected by the ultrasonic sensor to travel back and forth between the two ends of the nut inside the nut.

[0044] According to the preset calibration formula, the real-time axial force of the nut corresponding to the measured sound time is obtained.

[0045] Optionally, the preset calibration formula is: F=[(t-t0)-k1(T-T0)]k2;

[0046] Wherein, F is the axial force of the nut, t is the measured acoustic time, t0 is the initial acoustic time after the nut is installed, T is the measured temperature of the nut, T0 is the initial temperature when the nut is calibrated under load, k1 is the temperature calibration coefficient, and k2 is the load calibration coefficient.

[0047] Optionally, before acquiring the real-time axial force data of the nut during train operation, the method further includes:

[0048] During the assembly stage of the air supply pipeline connection system, as detected by the ground detection device, the static axial force generated after the nut is connected to the pipe joint is obtained.

[0049] The initial acoustic time is calibrated using the static axial force and according to the preset calibration formula.

[0050] Optionally, the first preset threshold includes a dynamic threshold, and before determining whether the real-time axial force of the nut remains less than the first preset threshold for a first preset time, it further includes:

[0051] After the train has accumulated a preset time or a preset mileage, a dynamic threshold range of axial force under different working conditions is formed based on the historical axial force data of the train under different working conditions.

[0052] The dynamic threshold is determined based on the lower limit of the dynamic threshold range.

[0053] Optionally, based on historical axial force data under different train operating conditions, a dynamic threshold range for axial force under different operating conditions is formed, including:

[0054] Based on historical axial force data of trains under different operating conditions, calculate the 95% confidence interval of axial force under different operating conditions;

[0055] Determining the dynamic threshold based on the lower limit of the dynamic threshold range includes:

[0056] Based on the 95% confidence interval, the dynamic threshold is obtained according to the formula Lnew=min(P5)-δ;

[0057] Wherein, Lnew is the dynamic threshold, P5 is the 5th percentile value of the 95% confidence interval, min(P5) is the minimum value of the 5th percentile value corresponding to all operating conditions, and δ is the preset normal number.

[0058] Optionally, the first preset threshold includes an initial threshold, and before determining whether the real-time axial force of the nut remains less than the first preset threshold for a first preset time, it further includes:

[0059] The critical axial force of the nut at the connection between the air supply pipeline and the pipe joint, as detected by the ground detection device, is obtained when the air supply pipeline connection system is about to leak air.

[0060] Before the train has accumulated a preset time or a preset mileage, the critical axial force is used as the initial threshold.

[0061] An axial force assessment system for an air supply duct connection system is applied to the air supply duct connection system of a train. The air supply duct connection system includes a pipe, a pipe fitting, and a nut. The pipe and the pipe fitting are sealed together via a flared conical surface mating structure. The nut is threadedly connected to the pipe fitting to ensure tight contact between the pipe and the pipe fitting. The axial force assessment system for the air supply duct connection system includes:

[0062] A ground-based testing device is used to acquire the static axial force generated after the nut is connected to the pipe joint during the assembly stage of the air supply pipeline connection system.

[0063] An online monitoring device is used to acquire real-time axial force data of the nut during train operation;

[0064] The data processing system is used to implement any of the above-mentioned methods for evaluating the axial force of the air supply pipeline connection system.

[0065] An axial force assessment device for an air supply pipeline connection system is applied to the air supply pipeline connection system of a train. The air supply pipeline connection system includes a pipe, a pipe joint, and a nut. The pipe and the pipe joint are sealed and abutted by a flared conical surface mating structure. The nut is threadedly connected to the pipe joint so that the pipe and the pipe joint are tightly abutted.

[0066] The axial force assessment device for the air supply pipeline connection system includes:

[0067] A real-time axial force acquisition module is used to acquire real-time axial force data of the nut during train operation;

[0068] An axial force determination module is used to determine, based on the real-time axial force data, whether the real-time axial force of the nut remains less than a first preset threshold for a first preset time.

[0069] The first-level early warning module is used to trigger a first-level early warning if the real-time axial force of the nut is less than the first preset threshold for the first preset time.

[0070] An axial force assessment device for an air supply duct connection system includes:

[0071] Memory, used to store computer programs;

[0072] A processor is used to implement the steps of any of the above-described methods for evaluating the axial force of an air supply duct connection system when executing the computer program.

[0073] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above-described methods for evaluating the axial force of an air supply duct connection system.

[0074] The axial force evaluation method for air supply pipeline connection systems provided by this invention has at least the following beneficial effects:

[0075] By monitoring the axial force of the nut online in real time and comparing it with a first preset threshold, it is determined whether the axial force is continuously lower than the first preset threshold. When the real-time axial force of the nut is less than the first preset threshold for a first preset time, it indicates that the axial force of the nut does not meet the requirements and there is a risk of leakage. Therefore, a first-level warning is triggered at this time to realize the online safety assessment of the sealing performance of the air supply pipeline connection system. This is to remind the staff that there is a risk of air leakage at the connection between the pipes and pipe joints of the air supply pipeline connection system, so that the staff can carry out maintenance in time to reduce sudden leakage failures.

[0076] The axial force evaluation system for air supply pipeline connection system provided by the present invention is used to implement the above-mentioned axial force evaluation method for air supply pipeline connection system, and has at least the beneficial effects of the above-mentioned axial force evaluation method for air supply pipeline connection system.

[0077] The axial force evaluation device for the air supply pipeline connection system provided by the present invention corresponds to the above-mentioned axial force evaluation method for the air supply pipeline connection system and has at least the beneficial effects of the above-mentioned axial force evaluation method for the air supply pipeline connection system.

[0078] The axial force assessment device for the air supply pipeline connection system provided by the present invention corresponds to the above-mentioned axial force assessment method for the air supply pipeline connection system and has at least the beneficial effects of the above-mentioned axial force assessment method for the air supply pipeline connection system.

[0079] The computer-readable storage medium provided by the present invention corresponds to the above-described method for evaluating the axial force of the air supply duct connection system and has at least the beneficial effects of the above-described method for evaluating the axial force of the air supply duct connection system. Attached Figure Description

[0080] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0081] Figure 1 A flowchart illustrating an axial force evaluation method for an air supply duct connection system provided in a specific embodiment of the present invention;

[0082] Figure 2 A flowchart illustrating an axial force evaluation method for an air supply duct connection system, provided in another specific embodiment of the present invention;

[0083] Figure 3 This is a structural block diagram of the axial force evaluation device for the air supply pipeline connection system provided in a specific embodiment of the present invention;

[0084] Figure 4 The structural block diagram of the axial force evaluation device for the air supply pipeline connection system provided in a specific embodiment of the present invention is shown.

[0085] Figure label:

[0086] 11-Real-time axial force acquisition module; 12-Axial force judgment module; 13-Level 1 early warning module;

[0087] 21-Memory; 22-Processor. Detailed Implementation

[0088] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0089] The core of this invention is to provide a method for evaluating the axial force of an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on axial force. Another core of this invention is to provide an axial force evaluation system for an air supply duct connection system, used to implement the above-mentioned method for evaluating the axial force of an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on axial force. Another core of this invention is to provide an axial force evaluation device for an air supply duct connection system, corresponding to the above-mentioned method for evaluating the axial force of an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on axial force. Another core of this invention is to provide a computer-readable storage medium, corresponding to the above-mentioned method for evaluating the axial force of an air supply duct connection system, so as to evaluate the sealing performance of the air supply duct connection system based on axial force.

[0090] Please refer to Figure 1 This invention provides a method for evaluating the axial force of an air supply duct connection system, applied to the air supply duct connection system of a train. The air supply duct connection system includes a pipe, a pipe fitting, and a nut. The pipe and the pipe fitting are sealed together by a flared conical surface mating structure. The nut is threadedly connected to the pipe fitting to ensure tight contact between the pipe and the pipe fitting. The method for evaluating the axial force of the air supply duct connection system includes steps S1-S3:

[0091] S1: Obtain real-time axial force data of the nut during train operation.

[0092] It should be noted that the real-time axial force data here refers to the dynamic axial force value data of the nut collected by the online monitoring device while the train is in operation, which reflects the preload state of the nut. This embodiment does not specifically limit the online monitoring device, as long as it can collect the real-time axial force data of the nut during train operation. For example, the online monitoring device is the ultrasonic sensor located on one end face of the nut, as mentioned below.

[0093] S2: Based on the real-time axial force data, determine whether the real-time axial force of the nut has been less than the first preset threshold for a first preset time.

[0094] It should be noted that the first preset threshold refers to the minimum safe axial force required to maintain a reliable seal in the air supply duct connection system. The first preset threshold can be a given axial force value or a dynamic threshold obtained based on historical train operation data. Furthermore, this embodiment does not limit the specific value of the first preset time; the first preset time is used to eliminate the influence of short-term fluctuations.

[0095] S3: If so, trigger a Level 1 warning.

[0096] It should be noted that a Level 1 warning means that when the real-time axial force of the nut remains below a first preset threshold for a first preset time, a corresponding warning message is output. This warning message can be a pop-up window on the vehicle monitoring interface, an audible alert, or an indicator light alarm. A Level 1 warning indicates a potential sealing risk at the connection points of the air supply duct system, but has not yet reached a level of serious air leakage, allowing for early detection and maintenance of the deteriorated airtightness of the air supply duct system.

[0097] In other words, this embodiment of the invention monitors the axial force of the nut online in real time and compares the real-time axial force of the nut with a first preset threshold to determine whether the axial force is continuously lower than the first preset threshold. When the real-time axial force of the nut is less than the first preset threshold for a first preset time, it indicates that the axial force of the nut does not meet the requirements and there is a risk of leakage. Therefore, a first-level warning is triggered at this time to realize the online safety assessment of the sealing performance of the air supply pipeline connection system, so as to remind the staff that there is a risk of air leakage at the connection between the pipes and pipe joints of the air supply pipeline connection system, so that the staff can perform maintenance in time to reduce sudden leakage failures.

[0098] Further, please refer to Figure 2 In some embodiments, after determining whether the real-time axial force of the nut has been less than a first preset threshold for a first preset time, steps S4-S6 are further included:

[0099] S4: If the real-time axial force of the nut continues for a first preset time and is not less than a first preset threshold, the axial force decay rate of the nut is obtained based on the real-time axial force data.

[0100] It should be noted that the axial force decay rate refers to the rate of change of axial force per unit time, which reflects the trend of axial force change.

[0101] S5: Determine whether the axial force decay rate continues for a second preset time longer than the second preset threshold.

[0102] It should be noted that the second preset threshold refers to the maximum normal attenuation rate of the axial force allowed by the air supply duct connection system. Additionally, the second preset time is used to avoid misjudgments caused by short-term operating disturbances.

[0103] S6: If so, trigger a level 2 warning.

[0104] It should be noted that a Level 2 warning refers to the output of a warning message when the axial force attenuation rate of the nut exceeds a second preset threshold for a second preset time. This warning message can be a pop-up window on the vehicle monitoring interface, an audible alert, or an indicator light alarm. Level 1 and Level 2 warnings represent different degrees of deterioration in the sealing performance of the air supply duct connection system.

[0105] In other words, this embodiment provides an early warning based on the trend of axial force change when the axial force is not lower than the first preset threshold. It can be understood that when the axial force is not lower than the first preset threshold, but the axial force is continuously and rapidly decreasing, it indicates that the air supply pipeline connection system may have entered the stage of deterioration of sealing performance, and a risk warning needs to be issued in advance, that is, to identify the trend of deterioration of sealing performance in advance.

[0106] Further, please refer to Figure 2 In some embodiments, after acquiring the real-time axial force data of the nut during train operation, the method further includes:

[0107] S7: Based on real-time axial force data, obtain the axial force fluctuation amplitude and axial force fluctuation frequency of the nut.

[0108] In other words, this embodiment extracts the dynamic oscillation characteristics of the axial force based on real-time axial force data, namely, the axial force fluctuation amplitude and the axial force fluctuation frequency. The axial force fluctuation amplitude refers to the range of change of the axial force relative to its average value within a certain time range. The magnitude of the axial force fluctuation amplitude can reflect the degree of abnormality. For example, under normal operating conditions, affected by factors such as train vibration, braking impact, or track irregularities, the axial force will fluctuate slightly. For instance, the normal fluctuation range of the axial force is ≤±3%. However, under air leakage conditions, due to enhanced airflow pulsation, the axial force oscillation will be significantly enhanced. Furthermore, the axial force fluctuation frequency refers to the periodic characteristic of the axial force oscillation.

[0109] S8: Obtain pipeline pressure data of the air supply pipeline connection system, and calculate the pipeline pressure fluctuation frequency based on the pipeline pressure data.

[0110] It should be noted that pipeline pressure data refers to the real-time measured internal pressure parameters of the air supply pipeline. Pipeline pressure fluctuation frequency refers to the periodic frequency of pipeline pressure oscillation, which can reflect the characteristics of leaking airflow.

[0111] S9: Determine whether the axial force fluctuation amplitude is greater than the third preset threshold, and determine whether the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency.

[0112] It should be noted that the third preset threshold refers to the maximum allowable normal axial force fluctuation range. When the axial force fluctuation range exceeds the third preset threshold, it indicates that abnormal oscillation has occurred. For example, the axial force fluctuation range can be ±10%. In addition, the matching of axial force fluctuation frequency and pipeline pressure fluctuation frequency means that the axial force fluctuation frequency and the pipeline pressure fluctuation frequency are consistent.

[0113] S10: If the axial force fluctuation amplitude is greater than the third preset threshold, and the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency, an emergency warning is triggered.

[0114] In other words, when the axial force fluctuation amplitude exceeds the third preset threshold and the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency simultaneously, based on dual-condition coupling, it is ensured that the abnormal oscillation originates from air leakage, thus triggering an emergency warning. The emergency warning indicates a significant risk of air leakage in the air supply pipeline connection system.

[0115] In other words, in this embodiment, even if the real-time axial force of the nut does not last for a first preset time less than a first preset threshold, or the axial force decay rate does not last for a second preset time greater than a second preset threshold, it is still possible that the air supply pipeline connection system has leaked, causing the internal airflow to pulsate periodically, thereby causing abnormal high-frequency fluctuations in the axial force of the nut. This embodiment identifies whether the air supply pipeline has leaked significantly based on the judgment of the axial force fluctuation amplitude and the coupling relationship between the axial force fluctuation frequency and the pipeline pressure fluctuation frequency, and issues an emergency warning in a timely manner to improve the safety of train operation.

[0116] In addition, to improve the accuracy of issuing the first-level warning, in some embodiments, after determining whether the real-time axial force of the nut has been less than a first preset threshold for a first preset time, the following steps are also included:

[0117] If the real-time axial force of the nut is less than the first preset threshold for a first preset time, the pipeline pressure fluctuation amplitude and the vibration acceleration of the nut in the air supply pipeline connection system are obtained.

[0118] Calculate the first correlation coefficient between real-time axial force, pipeline pressure fluctuation amplitude, and vibration acceleration;

[0119] Determine whether the first relevance coefficient is greater than or equal to the fourth preset threshold;

[0120] If so, a Level 1 warning will be triggered.

[0121] It should be noted that pipeline pressure fluctuation amplitude refers to the range of variation in internal pipeline pressure around the average pressure value. Vibration acceleration refers to the dynamic acceleration response of the nut when subjected to vibration excitation during operation. The first correlation coefficient refers to the degree of correlation between real-time axial force, pipeline pressure fluctuation amplitude, and vibration acceleration. The first correlation coefficient can be the Pearson coefficient, and its calculation method can be found in relevant technologies, which will not be elaborated here.

[0122] In other words, in this embodiment, when the real-time axial force of the nut remains less than a first preset threshold for a first preset time, before triggering a first-level warning, the system further determines whether there is a coupling relationship between the real-time axial force, the pipeline pressure fluctuation amplitude, and the vibration acceleration. When the first correlation coefficient between the real-time axial force, the pipeline pressure fluctuation amplitude, and the vibration acceleration is greater than or equal to a fourth preset threshold, it indicates that the three are highly correlated, indicating that the current decrease in axial force is not a random fluctuation. This allows for a more accurate identification of the true sealing degradation state of the air supply pipeline connection system and reduces the probability of false alarms. For example, the fourth preset threshold is 0.8.

[0123] In addition, to improve the accuracy and reliability of the secondary warning, in some embodiments, after determining whether the axial force attenuation rate continues for a second preset time greater than a second preset threshold, the following steps are also included:

[0124] If the axial force attenuation rate continues for a second preset time longer than a second preset threshold, the pipeline pressure fluctuation amplitude of the train's air supply pipeline is obtained.

[0125] Calculate the second correlation coefficient between the axial force attenuation rate and the pipeline pressure fluctuation amplitude;

[0126] Determine whether the second relevance coefficient is greater than or equal to the fifth preset threshold;

[0127] If so, a Level 2 warning will be triggered.

[0128] In other words, in this embodiment, when the axial force attenuation rate persists for a second preset time longer than a second preset threshold, before triggering a secondary warning, a further determination is made as to whether there is a coupling relationship between the axial force attenuation rate and the pipeline pressure fluctuation amplitude. When the second correlation coefficient between the axial force attenuation rate and the pipeline pressure fluctuation amplitude is greater than or equal to a fifth preset threshold, it indicates that there is a high correlation between the two, indicating that the air supply pipeline connection system has entered a continuous abnormal state caused by seal deterioration. Based on the axial force attenuation trend and the coupling relationship between the axial force attenuation rate and the pipeline pressure fluctuation amplitude, a secondary warning is issued, thereby ensuring the accuracy and reliability of the secondary warning. For example, the fifth preset threshold is 0.8. The second correlation coefficient refers to the degree of correlation between the axial force attenuation rate and the pipeline pressure fluctuation amplitude. The second correlation coefficient can be the Pearson coefficient, and its calculation method can be referred to relevant technologies, which will not be elaborated here.

[0129] In addition, to improve the accuracy and reliability of emergency warnings, in some embodiments, after determining whether the axial force fluctuation amplitude is greater than a third preset threshold and whether the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency, the method further includes:

[0130] If the amplitude of axial force fluctuation is greater than the third preset threshold, and the frequency of axial force fluctuation matches the frequency of pipeline pressure fluctuation, the main peak frequency of vibration of the pipeline connection system is obtained.

[0131] Calculate the third correlation coefficient between the axial force fluctuation frequency and the vibration peak frequency;

[0132] Determine whether the third relevance coefficient is greater than or equal to the sixth preset threshold;

[0133] If so, trigger an emergency warning.

[0134] It should be noted that the dominant vibration frequency refers to the frequency at which the structural vibration is most intense in the structural vibration spectrum. The third correlation coefficient refers to the degree of correlation between the axial force fluctuation frequency and the dominant vibration frequency. The third correlation coefficient can be the Pearson coefficient, and its calculation method can be found in relevant technologies, which will not be elaborated here. For example, the sixth preset threshold is 0.8.

[0135] In other words, in this embodiment, when the axial force fluctuation amplitude is greater than the third preset threshold and the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency, before triggering the emergency warning, it is further determined whether there is a coupling relationship between the axial force fluctuation frequency and the vibration peak frequency. When the third correlation coefficient between the axial force fluctuation frequency and the vibration peak frequency is greater than or equal to the sixth preset threshold, it indicates that there is a high correlation between the two, indicating that the air leakage has caused structural resonance and the air supply pipeline connection system has entered a serious abnormal state, thus triggering the emergency warning.

[0136] It should be noted that the above embodiments do not limit the specific method of obtaining the real-time axial force data of the nut during train operation, as long as the real-time axial force data of the nut during train operation can be obtained.

[0137] In some embodiments, acquiring real-time axial force data of the nut during train operation includes:

[0138] The measured sound time is the time it takes for the ultrasonic wave detected by the ultrasonic sensor installed at one end of the nut to travel back and forth between the two ends of the nut. The ultrasonic sensor generates ultrasonic waves using the piezoelectric effect.

[0139] According to the preset calibration formula, the real-time axial force of the nut corresponding to the measured sound time is obtained.

[0140] In other words, this embodiment uses an ultrasonic sensor on one end of the nut, for example, a permanent thin-film sensor. Based on the theory of acoustoelasticity, when the nut is subjected to stress, its crystal structure undergoes slight deformation, causing a change in the propagation speed of ultrasonic waves in the material. This results in a change in the acoustic time of the ultrasonic waves traveling back and forth between the two ends inside the nut. That is, by utilizing the piezoelectric effect of the ultrasonic sensor, ultrasonic waves are generated inside the nut. By measuring the time it takes for the ultrasonic waves to travel back and forth inside the nut (i.e., the measured acoustic time), the real-time axial force state of the nut can be indirectly reflected. Based on a pre-established calibration formula, the real-time axial force of the nut can be obtained. In other words, by collecting the real-time acoustic time through the ultrasonic sensor, the real-time axial force data of the nut during train operation can be obtained. This enables online real-time monitoring of axial force without manual intervention, and is suitable for long-term detection needs under complex working conditions.

[0141] It should be noted that this embodiment does not impose specific limitations on the above-mentioned preset calibration formula, as long as it can reflect the relationship between the axial force of the nut and the sound time.

[0142] In some embodiments, the preset calibration formula is: F=[(t-t0)-k1(T-T0)]k2; where F is the axial force of the nut, t is the measured sound time, t0 is the initial sound time after the nut is installed, T is the measured temperature of the nut, T0 is the initial temperature when the nut is calibrated under load, k1 is the temperature calibration coefficient, and k2 is the load calibration coefficient.

[0143] In other words, this embodiment considers the influence of temperature and load changes on ultrasonic wave propagation when determining the preset calibration formula, and performs temperature compensation correction and load compensation correction to ensure measurement accuracy.

[0144] It should be noted that the temperature calibration coefficient k1 is obtained through temperature calibration experiments, which include:

[0145] Place the nut inside the temperature chamber;

[0146] Adjust the ambient temperature inside the temperature chamber according to the preset temperature step size;

[0147] The propagation time of ultrasonic waves at different temperatures was collected;

[0148] The temperature calibration coefficient k1 is obtained by fitting the relationship between acoustic time and temperature.

[0149] In practical applications, temperature calibration experiments show that sound time increases with increasing temperature. Through data fitting, sound time and temperature exhibit an approximately linear relationship. Therefore, the temperature calibration coefficient k1 in the preset calibration formula can be understood as the slope value of sound time changing with temperature during temperature calibration.

[0150] Additionally, it should be noted that the load calibration factor k2 is obtained through load calibration experiments, which include:

[0151] Under the preset temperature conditions, install the nut on the tensile testing machine;

[0152] Apply the load step by step according to the preset load increment;

[0153] Record the propagation time of ultrasonic waves under different loads;

[0154] The load calibration coefficient k2 is obtained by fitting the relationship between the load and the acoustic time difference.

[0155] In practical applications, load calibration experiments show that as the load (equivalent to the axial force on the nut) increases, the acoustic time also gradually increases. Through data fitting, it can be found that the acoustic time and the load difference are approximately linearly related. Therefore, the load calibration coefficient k2 in the preset calibration formula can be understood as the slope of the load change with respect to the acoustic time difference.

[0156] In addition, in actual online monitoring, by directly measuring the measured acoustic time t of ultrasonic wave propagation and the measured temperature T of the nut, the real-time axial force of the nut can be obtained according to the aforementioned preset calibration formula; the difference in axial force, that is, the dynamic change in axial force, can also be calculated. For example, the axial force at the first moment is: F1=[(t1-t0)-k1(T1-T0)]k2; the axial force at the second moment is: F2=[(t2-t0)-k1(T2-T0)]k2, and the difference in axial force between the two moments is: ∆F=F2-F1=[(t2-t0)-k1(T2-T0)]k2-[(t1-t0)-k1(T1-T0)]k2=[(t2-t1)-k1(T2-T1)] k2, that is, ∆F=[∆t-k1∆T]k2, as can be seen from this formula, this formula eliminates the error caused by the initial sound time t0 and the initial state of the nut (such as the thread depth, nut structure, etc.).

[0157] In addition, to ensure the accuracy of the initial acoustic time t0, in some embodiments, before acquiring the real-time axial force data of the nut during train operation, the following steps are also included:

[0158] During the assembly stage of the air supply pipeline connection system detected by the ground detection device, the static axial force generated after the nut and pipe joint are connected is obtained.

[0159] The initial sound time is calibrated using static axial force and according to a preset calibration formula.

[0160] In other words, this embodiment utilizes a ground-based detection device to detect the static axial force generated after the nut and pipe joint are connected during the assembly stage of the air supply duct connection system. Because the ground-based detection device has fewer interference factors, its influence on the actual axial force value is smaller. Therefore, the measurement result is closer to the true axial force magnitude. This embodiment uses the static axial force detected by the ground-based detection device as a benchmark to calibrate the initial acoustic time of online monitoring, thereby eliminating system errors and combining ground-based detection with online monitoring to improve the consistency of data across the entire scenario. It can be understood that the static axial force F can be measured by the ground-based detection device. Simultaneously, during the assembly stage of the air supply duct connection system, after the nut and pipe joint are connected, the ultrasonic sensor measures the current actual acoustic time t. By obtaining the measured temperature T of the nut, and according to the preset calibration formula F=[(t-t0)-k1(T-T0)]k2, the corrected t0 can be calculated in reverse. The corrected t0 is used as a benchmark for online monitoring of the real-time axial force of the nut.

[0161] It should be noted that this embodiment does not limit the specific structure of the ground detection device, as long as the ground detection device can detect the static axial force generated after the nut and pipe joint are connected during the assembly stage of the air supply pipeline connection system. For example, the ground detection device may include a simulated pipe joint, a simulated pipe, a simulated nut, a simulated gasket, a pressure sensor, and a base. The connection structure between the simulated pipe joint and the simulated pipe is the same as the connection structure between the pipe and the pipe joint in the air supply pipeline connection system. The thread connection parameters between the simulated nut and the simulated pipe are the same as the thread connection parameters between the nut and the pipe joint in the air supply pipeline connection system. The contact state between the simulated nut and the simulated gasket is the same as the contact state between the nut and the gasket in the air supply pipeline connection system. The pressure sensor is located between the base and the simulated pipe joint and is an external sensor. When the simulated nut and the simulated pipe joint are threadedly connected, the axial force is directly measured using the pressure sensor. Using a ground-based testing device, a simulated nut is tightened with a torque wrench. Different torques are applied to pipes of different specifications, and the axial force is detected by a pressure sensor. This axial force is the nut's axial force. Nuts of the same specification can be tested multiple times, and the average value of the multiple tests is taken as the static axial force.

[0162] In some embodiments, the first preset threshold includes a dynamic threshold, and before determining whether the real-time axial force of the nut remains less than the first preset threshold for a first preset time, the method further includes:

[0163] After the train has accumulated a preset time or a preset mileage, a dynamic threshold range of axial force under different working conditions is formed based on the historical axial force data of the train under different working conditions.

[0164] The dynamic threshold is determined based on the lower limit of the dynamic threshold range.

[0165] In other words, this embodiment adaptively updates the dynamic threshold of axial force corresponding to different working conditions based on historical axial force data. After the train has accumulated a certain time or mileage, it constructs a safe range of axial force corresponding to each working condition based on the historical axial force data collected over a long period of time or mileage under different operating conditions. That is, the dynamic threshold range of axial force under different working conditions. The lower limit value is extracted from the dynamic threshold range, and the dynamic threshold is determined based on the lower limit value as the standard for judging the real-time axial force of the nut. In other words, this scheme adaptively corrects the first preset threshold during train operation, so that the first preset threshold matches different working conditions, reduces the false alarm rate, and improves the accuracy of long-term monitoring.

[0166] Furthermore, in some embodiments, based on historical axial force data under different train operating conditions, a dynamic threshold range for axial force under different operating conditions is formed, including:

[0167] Based on historical axial force data of trains under different operating conditions, calculate the 95% confidence interval of axial force under different operating conditions;

[0168] The dynamic threshold is determined based on the lower limit of the dynamic threshold range, including:

[0169] Based on the 95% confidence interval, the dynamic threshold is obtained according to the formula Lnew=min(P5)-δ;

[0170] Where Lnew is the dynamic threshold, P5 is the 5th percentile value of the 95% confidence interval, min(P5) is the minimum value of the 5th percentile value corresponding to all operating conditions, and δ is the preset normal number.

[0171] In other words, after the train has accumulated a preset time or mileage, and enough operating condition data has been collected, the historical axial force data is classified according to operating conditions. For example, operating conditions include vehicle braking, vehicle traction, different vehicle speeds, vehicle static conditions, and different temperatures. Then, for each type of operating condition, the 95% confidence interval of the corresponding axial force value is calculated. Based on the 95% confidence interval of the axial force value, the 5th percentile value P5 of each operating condition is determined. The minimum value of the 5th percentile value P5 of all operating conditions, i.e., min(P5), is used as the lower limit of the dynamic threshold interval. Then, min(P5)-δ is used as the dynamic threshold. δ is a pre-set positive number.

[0172] For example, all real-time axial force data collected under the same operating conditions (such as the same temperature and pressure) within a preset time or mileage (e.g., a period of time in the past, such as the last 7 days) are sorted from smallest to largest. The real-time axial force value at the 5th percentile is the 5th percentile value P5. This indicates that within the preset time or mileage, the real-time axial force value is higher than P5 95% of the time, and only at 5% of extreme moments is the real-time axial force value lower than P5. P5 represents the normal fluctuation limit under this operating condition. Furthermore, it is understood that during train operation, multiple 95% confidence intervals for axial force will occur. In this embodiment, the minimum value of the 5th percentile value P5 among the 95% confidence intervals corresponding to all operating conditions is taken as the lower limit of the dynamic threshold interval. Based on the lower limit value min(P5), δ is further reduced as a buffer to prevent false alarms caused by random noise or small statistical fluctuations in the data. Finally, Lnew is used as the first preset threshold for judging the real-time axial force of the nut at the current moment. If the real-time axial force of the nut monitored in real time is lower than Lnew, a first-level warning is issued.

[0173] Furthermore, in some embodiments, the first preset threshold includes an initial threshold, and before determining whether the real-time axial force of the nut remains less than the first preset threshold for a first preset time, it further includes:

[0174] The critical axial force of the nut at the point where air leakage is about to occur in the air supply pipeline connection system detected by the ground detection device;

[0175] Before the train accumulates a preset time or a preset mileage, the critical axial force is used as the initial threshold.

[0176] In other words, in the initial stage, for example, before the train has accumulated a preset time or preset mileage, the critical axial force detected by the ground detection device is used as the first preset threshold; after the train has accumulated a preset time or preset mileage, the above method is used to determine a dynamic threshold as the first preset threshold. This scheme can ensure the accuracy of the first preset threshold.

[0177] In addition, in some embodiments, the method for evaluating the axial force of the air supply duct connection system further includes:

[0178] The signal input from the manual calibration interface is acquired, and the first preset threshold, initial acoustic time, and / or the drift coefficient of the ultrasonic sensor are reset.

[0179] In addition to the above-mentioned method for evaluating the axial force of the air supply duct connection system, the present invention also provides an axial force evaluation system for the air supply duct connection system. The axial force evaluation system for the air supply duct connection system includes a ground detection device, an online monitoring device, and a data processing system. The ground detection device is used to acquire the static axial force generated after the nut and pipe joint are connected during the assembly stage of the air supply duct connection system. The online monitoring device is used to acquire the real-time axial force data of the nut during train operation. The data processing system is used to implement the axial force evaluation method for the air supply duct connection system disclosed in any of the above embodiments.

[0180] In other words, the axial force assessment system for the air supply pipeline connection system can realize the axial force assessment method for the air supply pipeline connection system disclosed in any of the above embodiments, and at least has the beneficial effects of the above-mentioned axial force assessment method for the air supply pipeline connection system, which will not be elaborated here.

[0181] Corresponding to the above embodiment of the axial force assessment method for air supply duct connection system, this embodiment of the invention also provides an axial force assessment device for air supply duct connection system. The axial force assessment device for air supply duct connection system described below can be referred to in correspondence with the axial force assessment method for air supply duct connection system described above.

[0182] Please refer to Figure 3 This is the structural frame of the axial force assessment device for an air supply pipeline connection system provided in a specific embodiment of the present invention. This axial force assessment device for an air supply pipeline connection system is applied to the air supply pipeline connection system of a train. The air supply pipeline connection system includes a pipe, a pipe fitting, and a nut. The pipe and the pipe fitting are sealed together by a flared conical surface mating structure. The nut is threadedly connected to the pipe fitting to ensure tight contact between the pipe and the pipe fitting. The axial force assessment device for the air supply pipeline connection system includes:

[0183] The real-time axial force acquisition module 11 is used to acquire the real-time axial force data of the nut during train operation.

[0184] The axial force judgment module 12 is used to determine whether the real-time axial force of the nut has been less than a first preset threshold for a first preset time based on the real-time axial force data.

[0185] The first-level early warning module 13 is used to trigger a first-level early warning if the real-time axial force of the nut is less than a first preset threshold for a first preset time.

[0186] It can be seen that the axial force evaluation device for the air supply pipeline connection system is a virtual device corresponding to the axial force evaluation method for the air supply pipeline connection system. Therefore, the relevant description of the axial force evaluation device for the air supply pipeline connection system can refer to the axial force evaluation method for the air supply pipeline connection system, and it has at least the beneficial effects of the aforementioned axial force evaluation method for the air supply pipeline connection system.

[0187] For the embodiment of the axial force assessment method for the air supply duct connection system mentioned above, please refer to [link / example]. Figure 4 The diagram shows the structure of the axial force assessment device for the air supply duct connection system provided in the embodiment of the present invention. The axial force assessment device for the air supply duct connection system includes a memory 21 and a processor 22. The memory 21 is used to store computer programs. The processor 22 is used to execute the computer programs to implement the steps of the axial force assessment method for the air supply duct connection system disclosed in any of the above embodiments.

[0188] For an introduction to the axial force evaluation device for the air supply pipeline connection system provided by the present invention, please refer to the above embodiment of the axial force evaluation method for the air supply pipeline connection system. The present invention will not be described in detail here.

[0189] Corresponding to the above embodiments of the method for evaluating the axial force of the air supply duct connection system, this embodiment of the invention also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it can implement the steps of the method for evaluating the axial force of the air supply duct connection system disclosed in any of the above embodiments.

[0190] The computer-readable storage medium may include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0191] For a description of the computer-readable storage medium provided by this invention, please refer to the above embodiment of the axial force evaluation method for the air supply pipeline connection system. This invention will not be described in detail here.

[0192] Corresponding to the above embodiments of the method for evaluating the axial force of the air supply duct connection system, this invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the method for evaluating the axial force of the air supply duct connection system disclosed in any of the above embodiments.

[0193] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0194] The axial force assessment method, detection system, and evaluation system for the air supply pipeline connection system provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of this invention.

Claims

1. A method for evaluating the axial force of an air supply duct connection system, characterized in that, An air supply pipeline connection system for trains includes a pipe, a pipe fitting, and a nut. The pipe and the pipe fitting are sealed and abutted by a flared conical surface mating structure. The nut is threadedly connected to the pipe fitting to ensure that the pipe and the pipe fitting are tightly abutted. The method for evaluating the axial force of the air supply duct connection system includes: Acquire real-time axial force data of the nut during train operation; Based on the real-time axial force data, determine whether the real-time axial force of the nut has been less than a first preset threshold for a first preset time. If so, a Level 1 warning will be triggered.

2. The method for evaluating the axial force of an air supply pipeline connection system according to claim 1, characterized in that, After determining whether the real-time axial force of the nut has remained below a first preset threshold for a first preset time, the process further includes: If the real-time axial force of the nut continues for a period of time that is not less than the first preset threshold, the axial force attenuation rate of the nut is obtained based on the real-time axial force data. Determine whether the axial force attenuation rate continues for a second preset time greater than a second preset threshold; If so, a Level 2 warning will be triggered.

3. The method for evaluating the axial force of an air supply duct connection system according to claim 1, characterized in that, After acquiring the real-time axial force data of the nut during train operation, the process also includes: Based on the real-time axial force data, the axial force fluctuation amplitude and axial force fluctuation frequency of the nut are obtained; Obtain the pipeline pressure data of the air supply pipeline connection system, and calculate the pipeline pressure fluctuation frequency based on the pipeline pressure data; Determine whether the amplitude of the axial force fluctuation is greater than a third preset threshold, and determine whether the frequency of the axial force fluctuation matches the frequency of the pipeline pressure fluctuation; If the amplitude of the axial force fluctuation is greater than the third preset threshold, and the frequency of the axial force fluctuation matches the frequency of the pipeline pressure fluctuation, an emergency warning is triggered.

4. The method for evaluating the axial force of an air supply pipeline connection system according to claim 1, characterized in that, After determining whether the real-time axial force of the nut has remained below a first preset threshold for a first preset time, the process further includes: If the real-time axial force of the nut is less than the first preset threshold for the first preset time, the pipeline pressure fluctuation amplitude of the air supply pipeline connection system and the vibration acceleration of the nut are obtained. Calculate the first correlation coefficient between the real-time axial force, the pipeline pressure fluctuation amplitude, and the vibration acceleration; Determine whether the first correlation coefficient is greater than or equal to the fourth preset threshold; If so, trigger the Level 1 warning.

5. The method for evaluating the axial force of an air supply pipeline connection system according to claim 2, characterized in that, After determining whether the axial force attenuation rate continues for a second preset time greater than a second preset threshold, the method further includes: If the axial force attenuation rate continues for a period of time longer than the second preset threshold, the pipeline pressure fluctuation amplitude of the train's air supply pipeline is obtained. Calculate the second correlation coefficient between the axial force attenuation rate and the pipeline pressure fluctuation amplitude; Determine whether the second correlation coefficient is greater than or equal to the fifth preset threshold; If so, the level 2 warning will be triggered.

6. The method for evaluating the axial force of an air supply pipeline connection system according to claim 3, characterized in that, After determining whether the axial force fluctuation amplitude is greater than a third preset threshold and whether the axial force fluctuation frequency matches the pipeline pressure fluctuation frequency, the method further includes: If the amplitude of the axial force fluctuation is greater than the third preset threshold, and the frequency of the axial force fluctuation matches the frequency of the pipeline pressure fluctuation, the vibration peak frequency of the pipeline connection system is obtained. Calculate the third correlation coefficient between the axial force fluctuation frequency and the vibration peak frequency; Determine whether the third correlation coefficient is greater than or equal to the sixth preset threshold; If so, the aforementioned emergency warning will be triggered.

7. The method for evaluating the axial force of an air supply duct connection system according to any one of claims 1-6, characterized in that, Acquire real-time axial force data of the nut during train operation, including: When the measured sound detected by the ultrasonic sensor installed at one end of the nut is obtained, the ultrasonic sensor generates ultrasonic waves using the piezoelectric effect, and the measured sound time is the time it takes for the ultrasonic wave detected by the ultrasonic sensor to travel back and forth between the two ends of the nut inside the nut. According to the preset calibration formula, the real-time axial force of the nut corresponding to the measured sound time is obtained.

8. The method for evaluating the axial force of an air supply duct connection system according to claim 7, characterized in that, The preset calibration formula is: F=[(t-t0)-k1(T-T0)]k2; Wherein, F is the axial force of the nut, t is the measured acoustic time, t0 is the initial acoustic time after the nut is installed, T is the measured temperature of the nut, T0 is the initial temperature when the nut is calibrated under load, k1 is the temperature calibration coefficient, and k2 is the load calibration coefficient.

9. The method for evaluating the axial force of an air supply pipeline connection system according to claim 8, characterized in that, Before acquiring the real-time axial force data of the nut during train operation, the following steps are also included: During the assembly stage of the air supply pipeline connection system, as detected by the ground detection device, the static axial force generated after the nut is connected to the pipe joint is obtained. The initial acoustic time is calibrated using the static axial force and according to the preset calibration formula.

10. The method for evaluating the axial force of an air supply duct connection system according to any one of claims 1-6, characterized in that, The first preset threshold includes a dynamic threshold, and before determining whether the real-time axial force of the nut remains less than the first preset threshold for a first preset time, it further includes: After the train has accumulated a preset time or a preset mileage, a dynamic threshold range of axial force under different working conditions is formed based on the historical axial force data of the train under different working conditions. The dynamic threshold is determined based on the lower limit of the dynamic threshold range.

11. The method for evaluating the axial force of an air supply pipeline connection system according to claim 10, characterized in that, Based on historical axial force data of trains under different operating conditions, dynamic threshold ranges for axial force under different operating conditions are formed, including: Based on historical axial force data of trains under different operating conditions, calculate the 95% confidence interval of axial force under different operating conditions; Determining the dynamic threshold based on the lower limit of the dynamic threshold range includes: Based on the 95% confidence interval, the dynamic threshold is obtained according to the formula Lnew=min(P5)-δ; Wherein, Lnew is the dynamic threshold, P5 is the 5th percentile value of the 95% confidence interval, min(P5) is the minimum value of the 5th percentile value corresponding to all operating conditions, and δ is the preset normal number.

12. The method for evaluating the axial force of an air supply duct connection system according to any one of claims 1-6, characterized in that, The first preset threshold includes an initial threshold, and before determining whether the real-time axial force of the nut remains less than the first preset threshold for a first preset time, it further includes: The critical axial force of the nut at the connection between the air supply pipeline and the pipe joint, as detected by the ground detection device, is obtained when the air supply pipeline connection system is about to leak air. Before the train has accumulated a preset time or a preset mileage, the critical axial force is used as the initial threshold.

13. An axial force evaluation system for an air supply duct connection system, characterized in that, An air supply pipeline connection system for trains includes a pipe, a pipe fitting, and a nut. The pipe and the pipe fitting are sealed and abutted by a flared conical surface mating structure. The nut is threadedly connected to the pipe fitting to ensure that the pipe and the pipe fitting are tightly abutted. The axial force assessment system for the air supply pipeline connection system includes: A ground-based testing device is used to acquire the static axial force generated after the nut is connected to the pipe joint during the assembly stage of the air supply pipeline connection system. An online monitoring device is used to acquire real-time axial force data of the nut during train operation; A data processing system for implementing the axial force evaluation method for the air supply pipeline connection system as described in any one of claims 1-12.

14. An axial force evaluation device for an air supply duct connection system, characterized in that, An air supply pipeline connection system for trains includes a pipe, a pipe fitting, and a nut. The pipe and the pipe fitting are sealed and abutted by a flared conical surface mating structure. The nut is threadedly connected to the pipe fitting to ensure that the pipe and the pipe fitting are tightly abutted. The axial force assessment device for the air supply pipeline connection system includes: A real-time axial force acquisition module is used to acquire real-time axial force data of the nut during train operation; An axial force determination module is used to determine, based on the real-time axial force data, whether the real-time axial force of the nut remains less than a first preset threshold for a first preset time. The first-level early warning module is used to trigger a first-level early warning if the real-time axial force of the nut is less than the first preset threshold for the first preset time.

15. An axial force assessment device for an air supply duct connection system, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the method for evaluating the axial force of an air supply duct connection system as described in any one of claims 1 to 12 when executing the computer program.

16. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the axial force assessment method for an air supply duct connection system as described in any one of claims 1 to 12.

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