Ballastless track joint performance degradation monitoring method and system

Abstract

The invention provides a ballastless track joint performance degradation monitoring method and system, and relates to the technical field of track joint performance monitoring, and the method comprises the steps: knocking a ballastless track plate at a track joint through a force hammer to generate excitation, collecting a vertical vibration acceleration response signal through an acceleration sensor, and synchronously recording the knocking time and static parameters. The vertical vibration acceleration response signal is preprocessed, abnormal pulses and baseline drift are removed, a vibration event sample is formed, and joint mechanics characteristic parameters including a vibration frequency parameter reflecting rigidity degradation and a vibration attenuation parameter reflecting damping are extracted. According to the method, the joint performance evaluation index is calculated in combination with the static parameters, the degradation grade is evaluated after the evaluation index is compared with the preset threshold value, an early warning signal is triggered, the joint degradation grade and position information are provided, and monitoring and evaluation of the joint performance are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of track joint performance monitoring, in particular to a ballastless track joint performance deterioration monitoring method and system. BACKGROUND

[0002] Ballastless track has been widely used in high-speed railway, intercity railway and other fields due to its strong integrity, high stability and low maintenance cost. As a weak link in the structure of the ballastless track system, the track joint is subjected to the combined action of various complex factors such as periodic train load, environmental temperature change and foundation settlement for a long time, and is prone to deterioration phenomena such as joint stiffness reduction, damping performance change and local damage to the joint structure. These deterioration phenomena will directly affect the overall mechanical performance of the track, causing abnormal vibration phenomena during train operation, and even threatening train operation safety in severe cases. For track joint deterioration monitoring, current methods mainly rely on manual detection or periodic inspection by track detection vehicles. These traditional methods have problems such as long detection cycle, lack of real-time performance, high cost and large disturbance to normal operation, which makes it difficult to meet the current high-frequency and high-precision track maintenance requirements. In addition, manual detection often relies on experience, and the reliability and consistency of the detection results are poor, with the risk of detection omission and misjudgment.

[0003] Currently, some studies attempt to reflect the track state through vibration signals during train operation, but there are still many technical problems in practical application. First, there is a lot of noise and interference in the train vibration signal, and the vibration signal characteristics at the track joint position are relatively weak, making it difficult to accurately locate the joint position and extract effective signals. In addition, existing methods usually lack effective data processing techniques, making it difficult to extract key feature parameters of track joint deterioration from vibration signals, resulting in insufficient monitoring accuracy. Especially for changes in track joint stiffness and damping performance, there is currently no mature quantitative evaluation system, which cannot provide accurate judgment basis for the performance deterioration degree of the track joint. In summary, existing technologies still have significant deficiencies in real-time monitoring, data analysis and processing, and quantitative evaluation of track joint performance deterioration, and there is an urgent need for a new method that can accurately locate the track joint deterioration position, realize real-time quantitative analysis of joint performance and dynamic warning, to meet the efficient maintenance and safe operation requirements of railway lines.

[0004] The above information disclosed in the BACKGROUND section is only intended to strengthen the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present application is to provide a ballastless track joint performance deterioration monitoring method and system to solve the problems raised in the background.

[0006] To achieve the above object, the present application provides the following technical solutions: A method for monitoring performance degradation of a ballastless track joint, comprising the following specific steps: S1: A force hammer is used to strike a ballastless track slab at a joint to be monitored to generate an excitation, an acceleration sensor fixedly installed on a foundation structure corresponding to the joint is used to collect a vertical vibration acceleration response signal of the joint caused by the excitation, a striking time is recorded, and a vertical vibration acceleration signal segment associated with the joint is obtained; static force parameters of the joint, including temperature, pressure and pretightening force, are synchronously collected; S2: The vertical vibration acceleration signal segment is preprocessed to remove abnormal pulse signals and constant baseline drift in the data, and a joint vibration event sample is obtained; the abnormal pulse signals are transient signals exceeding a preset vibration amplitude range, and the constant baseline drift is a fixed offset continuously existing in the data; S3: Feature extraction is performed on the joint vibration event sample to obtain a feature parameter set for characterizing mechanical performance of the track joint, the feature parameter set including a vibration frequency feature parameter reflecting stiffness degradation of the joint and a vibration attenuation feature parameter reflecting damping of the joint; S4: Based on the vibration frequency feature parameter, the vibration attenuation feature parameter and the static force parameter, a joint performance evaluation index is determined, the joint performance evaluation index is compared with a preset evaluation threshold, based on a result of the comparison, a degradation level of the track joint to be monitored is determined, and a corresponding early warning signal is triggered, the early warning signal including the degradation level of the track joint to be monitored and position information of the joint.

[0007] Further, in S1, the foundation structure includes a track slab bearing platform, an inner wall of a trackside cable trench or a top of a box girder; For a longitudinal joint between track slabs, an acceleration sensor is fixed to a side surface of a track slab bearing platform on both sides of the joint, and is 0.3-0.5 m away from an edge of the joint; for a transverse joint, a sensor is installed on an inner wall of a trackside cable trench close to the joint or a top of a box girder directly below the joint; the sensor is connected to the foundation structure through a stainless steel support; A temperature sensor, a pressure sensor and a pretightening force sensor are pre-buried in the joint or a tensioning lock during track slab width joint remediation construction, and are respectively used to collect temperature, pressure and pretightening force data of the joint; A standard hammer with a force sensor is used to strike the ballastless track slab 1-2 fastener spacings closest to the joint to be monitored in a vertical direction. The force sensor is used to monitor the striking force in real time and ensures that the peak impact force of a single strike is stable within a preset rated range through a feedback device to generate a standard excitation with consistent energy. At the same time, an accelerometer is used to collect the vibration response at the joint to be monitored in real time and continuously record a signal of a fixed duration at a sampling frequency of not less than 10kHz to ensure complete capture of the waveform from the start of excitation, vibration transmission to complete vibration decay. Finally, a complete vertical vibration acceleration signal segment that strictly corresponds to this standard striking excitation is obtained, and the static parameters at the joint, including temperature, pressure and preload, are collected simultaneously.

[0008] Furthermore, abnormal pulse signals are identified in the vertical vibration acceleration signal segment. A preset vibration amplitude range is defined, and the vertical vibration acceleration signal segment is scanned point by point. When the amplitude of a signal point exceeds the preset vibration amplitude range, the signal point and its adjacent signal points that are consecutive and also exceed the range are determined to constitute abnormal pulse signals. For the identified abnormal pulse signals, an interpolation completion method is used for processing, and the closest abnormal pulse signal is used to complete the interpolation. Based on the mean of normal signal points, the complete data corresponding to the abnormal pulse signal is calculated by linear interpolation and replaced with the original abnormal pulse signal data. Constant baseline drift identification is performed on the vertical vibration acceleration signal after removing abnormal pulse signals. A stable segment without obvious vibration fluctuations is selected in the signal, and the mean value of all signal points in the stable segment is calculated. This mean value is used as the constant baseline drift amount. The constant baseline drift is removed by subtracting the constant baseline drift amount from the value of each signal point in the entire vertical vibration acceleration signal segment, and the joint vibration event sample is obtained. The method for determining the steady segment is as follows: the complete vertical vibration acceleration signal segment is divided into multiple time segments of equal length, and the standard deviation of the vibration signal amplitude of each time segment is calculated according to the following formula: ; In the formula, Indicates the first The standard deviation of the vibration signal amplitude for each time segment is used to quantify the degree of fluctuation in the signal amplitude within that segment. Index for the time segment; This indicates the total number of data points contained within a time segment. For the index of the data points, This represents the arithmetic mean of the vibration signal amplitudes at all data points within a time interval. Indicates the first vibration signal amplitude at each data point All time segments are traversed, and the first 5% of time segments with the smallest standard deviation are screened out, i.e. the stable segments without obvious vibration fluctuation. The preset vibration amplitude range is determined based on amplitude statistical results of historical vertical vibration acceleration signals under a normal state of the operating line.

[0009] Further, the specific execution process of S3 is as follows: The frequency domain signal is obtained by performing Fourier transform on the joint vibration time sample , and the formula is as follows: ; In the formula, is the joint vibration time sample, which is a time sequence signal; is the frequency; is the imaginary unit; is the circular constant; is the time variable; is the natural constant; The power spectral density is calculated based on the frequency domain signal , and the calculation formula is as follows: ; In the formula, is the power spectral density corresponding to the th frequency component, which is used to reflect the vibration energy distribution of the frequency component, is the index of the frequency component; represents the th frequency domain component after Fourier transform; is the fixed sampling frequency of the acceleration sensor; is the total number of signal points of the joint vibration time sample, which is obtained by counting the number of signal points in the sample; In the power spectral density curve , the frequency component with the maximum value of is identified and extracted, i.e. the main peak frequency, which is used to directly reflect the joint stiffness characteristics: when the joint stiffness decreases, it will shift to the low frequency direction; the frequency shift is defined as the vibration frequency characteristic parameter, and the calculation formula is as follows: ; In the formula, is the frequency shift, which is used to quantify the joint stiffness degradation degree; is the reference main peak frequency in the preset joint performance reference parameter set, which is determined according to historical data statistics under the normal state of the line.

[0010] Further, the time domain analysis method is used to analyze the attenuation characteristics of the joint vibration event sample, and the damping variation characteristics of the track joint are extracted, and the specific steps are as follows: The Hilbert transform is used to extract the vibration envelope of the joint vibration event sample In the formula, is the vibration envelope, which is used to represent the change trend of the signal vibration amplitude with time; is the joint vibration time sample, is the Hilbert transform of ; is the ratio of the circumference to the diameter; represents the value of the joint vibration time sample at time , is the integral variable; The vibration envelope is exponentially fitted to obtain the signal attenuation rate , and the signal attenuation rate is defined as the vibration attenuation characteristic parameter; The formula for calculating is as follows: In the formula, is the initial amplitude, is the signal attenuation rate, which is used to represent the change of the joint damping performance; is the system natural frequency; is the time variable; The frequency offset and the signal attenuation rate are integrated to form a characteristic parameter set for representing the mechanical performance of the track joint.

[0011] Further, based on the dimensionless vibration frequency characteristic parameter, the vibration attenuation characteristic parameter and the static force parameter, the joint performance evaluation index is determined, and the formula is as follows: In the formula, is the joint performance evaluation index, which is used to reflect the deterioration degree of the performance of the monitored ballastless track joint; is the signal attenuation rate, is the reference value of the signal attenuation rate; is the frequency offset; , and are preset weights; is the static force parameter, is the index of the static force parameter, respectively corresponds to the temperature, the pressure and the pre-tightening force,​​​​ corresponding to the ideal value of the static parameter.

[0012] Further, the joint performance evaluation index is compared with a preset evaluation threshold to determine the degradation level of the to-be-monitored track joint: If , it is determined that the performance level of the to-be-monitored track joint is normal. If , it is determined that the performance level of the to-be-monitored track joint is slightly degraded. If , it is determined that the performance level of the to-be-monitored track joint is moderately degraded. If , it is determined that the performance level of the to-be-monitored track joint is severely degraded. In the formula, , and are respectively a first evaluation threshold, a second evaluation threshold and a third evaluation threshold, which are determined according to statistical analysis of historical normal data and degraded data. According to the above comparison method, the degradation level of the to-be-monitored track joint is determined, and a corresponding early warning signal is triggered, wherein the early warning signal includes the degradation level of the to-be-monitored track joint and the position information of the joint.

[0013] The application further provides a ballastless track joint performance degradation monitoring system, which is used to execute the ballastless track joint performance degradation monitoring method, and comprises: A data acquisition module is configured to generate an excitation by knocking a ballastless track slab at a to-be-monitored ballastless track joint by a force hammer, acquire a vertical vibration acceleration response signal of the joint caused by the excitation by using an acceleration sensor fixedly installed on a corresponding basic structure of the joint, record a knocking time, and obtain a vertical vibration acceleration signal segment associated with the joint; and simultaneously acquire static parameters of the joint, including temperature, pressure and pretightening force. A data processing module is configured to pre-process the vertical vibration acceleration signal segment, remove abnormal pulse signals and constant baseline drift in the data, and obtain a joint vibration event sample; the abnormal pulse signals are transient signals exceeding a preset vibration amplitude range, and the constant baseline drift is a fixed offset continuously existing in the data. A vibration feature extraction module is configured to extract features of the joint vibration event sample, and obtain a feature parameter set for characterizing mechanical properties of the track joint, wherein the feature parameter set includes a vibration frequency feature parameter reflecting joint stiffness degradation and a vibration attenuation feature parameter reflecting joint damping. The joint performance evaluation module determines a joint performance evaluation index based on the vibration frequency characteristic parameter, the vibration attenuation characteristic parameter and the static force parameter, compares the joint performance evaluation index with a preset evaluation threshold, determines a deterioration level of the to-be-monitored track joint based on a comparison result, and triggers a corresponding early warning signal, wherein the early warning signal includes the deterioration level of the to-be-monitored track joint and position information of the joint.

[0014] Compared with the prior art, the present application has the following beneficial effects: The present application realizes real-time monitoring and data recording of the track joint performance by collecting the vertical vibration acceleration signal by using the on-board acceleration sensor during the train operation and positioning the position of the track joint in combination with the mileage position information. The method removes abnormal pulses and baseline drift in the signal by using pre-processing technology, thereby obtaining clear joint vibration event samples, and further extracts the stiffness change and damping change characteristics of the joint by using frequency domain analysis and time domain analysis, thereby constructing a performance evaluation system based on the frequency offset and the signal attenuation rate. By introducing the joint performance evaluation index, the present application realizes quantitative evaluation of the track joint performance, and dynamically triggers the early warning signal according to the deterioration level, thereby providing a direct basis for subsequent operation and maintenance decisions. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of the overall method of the present application. Figure 2 The figure is a schematic diagram of the overall system module of the present application. Figure 3 The figure is a parallel coordinate image of each item and the dependent variable in the joint performance evaluation index calculation formula. Figure 4 The figure is a line segment diagram of the frequency offset, the signal attenuation rate item and the joint performance evaluation index. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below in combination with specific embodiments.

[0017] It should be noted that the technical terms or scientific terms used in the present application should be understood as the general meaning understood by those skilled in the art unless otherwise defined. The terms "first", "second" and the like used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and the like mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and the like are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0018] Embodiments: Please refer to Figure 1 The present application provides a technical solution: A method for monitoring the performance degradation of a ballastless track joint, comprising the following specific steps: S1: A force hammer is used to knock the ballastless track slab at the joint to be monitored to generate an excitation, an acceleration sensor fixedly installed on the corresponding base structure of the joint is used to collect the vertical vibration acceleration response signal of the joint caused by the excitation, the time of knocking is recorded, and a vertical vibration acceleration signal segment associated with the joint is obtained; The static parameters of the joint are synchronously collected, including temperature, pressure and pretightening force; In the embodiment, the base structure includes a track slab bearing platform, a trackside cable trough inner wall or a box girder top. For the longitudinal joint between the track slabs, the acceleration sensor is fixed to the side surface of the track slab bearing platform on both sides of the joint, 0.3-0.5m away from the edge of the joint; for the transverse joint, the sensor is installed on the inner wall of the trackside cable trough close to the joint or the top of the box girder directly below the joint; the sensor is connected to the base structure through a stainless steel support; The temperature sensor, pressure sensor and pretightening force sensor are pre-buried in the joint or tension lock during the treatment construction of the track slab width joint, and are used to collect the temperature, pressure and pretightening force data of the joint, respectively; A standard force hammer equipped with a force sensor is used to vertically strike the ballastless track slab at 1-2 fastener spacings closest to the joint to be monitored, the force sensor is used to monitor the striking force in real time, and the feedback device is used to ensure that the impact force peak of a single strike is stable within the preset rated range, so as to generate a standard excitation with consistent energy; At the same time, an acceleration sensor is used to collect the vibration response at the joint to be monitored in real time, and a signal with a fixed time length is continuously recorded at a sampling frequency of not less than 10 kHz, so as to ensure that the full process waveform from the beginning of excitation, vibration transmission to complete attenuation of vibration is completely captured, and finally a complete vertical vibration acceleration signal segment strictly corresponding to this standard striking excitation is obtained, and the static force parameters of the joint are synchronously collected, including temperature, pressure and pretightening force.

[0019] In the embodiment, the sensor arrangement and collection method are as follows: during the track slab width-narrow joint treatment construction, the temperature sensor, the pressure sensor and the pretightening force sensor are pre-buried in the joint or the tension lock: the temperature sensor adopts PT100 type, is directly buried in the joint material to monitor the internal temperature distribution; the pressure sensor adopts BCLFT-F miniature column type tension and compression force sensor, is buried in the joint to monitor the pressure borne by the joint; the pretightening force sensor adopts SKP117 type, is installed at the tension lock, and is used to monitor the pretightening force state of the tension lock in real time. All sensor signal lines are introduced into the trackside cable slot vertically, and are protected and fixed through rubber pipes and standard fixtures, and finally are connected to the width-narrow joint comprehensive monitor to realize synchronous, continuous collection and remote transmission of data.

[0020] Collecting the vertical vibration acceleration response signal and the temperature, pressure, pretightening force and other parameters is based on the multi-dimensional characteristics of the performance degradation of the ballastless track joint: the vertical vibration acceleration signal directly reflects the stiffness and damping performance of the joint under dynamic excitation (reflected by frequency offset and attenuation characteristics), which is the core basis for evaluating the mechanical response ability of the joint; the temperature parameter is related to the stress state of the joint due to thermal expansion and cold contraction, and can capture the crack expansion or joint opening caused by temperature change; the pressure parameter represents the load transmission ability of the joint filling material, and its abnormal change can reflect the structural damage such as material crushing and separation from the joint; the pretightening force parameter reflects the constraint effectiveness of the connecting piece such as the tension lock, and is directly related to the overall stability of the joint. By synchronously collecting the above parameters, the dynamic mechanical characteristics and the static stress state can be analyzed cooperatively, and various degradation modes from material degradation to structural failure of the joint are covered, so as to provide complete data support for accurately evaluating the performance of the joint.

[0021] Step S1 generates excitation by force hammer striking on the ballastless track slab, and collects vibration response signals by combining acceleration sensors fixed on the corresponding base structure of the joint, and synchronously collects static force parameters. This method can obtain complete vibration acceleration signals corresponding to the excitation in a standardized and repeatable manner. At the same time, the force sensor monitors the striking force in real time and ensures the consistency of the excitation energy, thereby ensuring the accuracy and consistency of data collection. In addition, the synchronous collection of static force parameters provides key multi-dimensional data support for subsequent evaluation.

[0022] Compared with traditional monitoring techniques, this step can realize more accurate joint vibration response signal collection through standard force hammer excitation and high-precision sensor arrangement, and does not rely on external machinery or vehicle load, thereby avoiding the problem of unstable data caused by changes in the environment or operating conditions. At the same time, the optimized design of the sensor installation position effectively improves the sensitivity and applicability of signal collection. In addition, the synchronous collection of static force parameters provides a more reliable basis for comprehensive analysis and diagnosis of joint deterioration causes.

[0023] Step S1 lays the foundation for data collection and quality control of the overall scheme. By obtaining high-quality vertical vibration acceleration signal segments and static force parameters, it provides a reliable data source for signal preprocessing, feature extraction and performance evaluation in subsequent steps, ensuring the accuracy and traceability of the analysis results. At the same time, the standardized operation of this step simplifies the monitoring process, improves the operability and generalizability of the scheme in practical application, and ultimately realizes efficient monitoring and evaluation of the performance degradation of the track joint.

[0024] S2: pre-processes the vertical vibration acceleration signal segment to remove abnormal pulse signals and constant baseline drift in the data, and obtains a joint vibration event sample; the abnormal pulse signal is a transient signal that exceeds the preset vibration amplitude range, and the constant baseline drift is a fixed offset that continuously exists in the data; In this embodiment, the vertical vibration acceleration signal segment is subjected to abnormal pulse signal identification, and a preset vibration amplitude range is set. The vertical vibration acceleration signal segment is scanned in a point-by-point manner. When the amplitude of a signal point is detected to exceed the preset vibration amplitude range, it is determined that the signal point and the adjacent signal points that are continuous with the signal point and have amplitudes also exceeding the range constitute an abnormal pulse signal. For the identified abnormal pulse signal, the mean value of the nearest normal signal points of the abnormal pulse signal is taken as the basis, the completion data of the abnormal pulse signal corresponding position is calculated by linear interpolation, and the original abnormal pulse signal data is replaced; Constant baseline drift identification is performed on the vertical vibration acceleration signal after removing abnormal pulse signals. A stable segment without obvious vibration fluctuations is selected in the signal, and the mean value of all signal points in the stable segment is calculated. This mean value is used as the constant baseline drift amount. The constant baseline drift is removed by subtracting the constant baseline drift amount from the value of each signal point in the entire vertical vibration acceleration signal segment, and the joint vibration event sample is obtained. The method for determining the steady segment is as follows: the complete vertical vibration acceleration signal segment is divided into multiple time segments of equal length, and the standard deviation of the vibration signal amplitude of each time segment is calculated according to the following formula: ; In the formula, Indicates the first The standard deviation of the vibration signal amplitude for each time segment is used to quantify the degree of fluctuation in the signal amplitude within that segment. The larger the value, the greater the fluctuation of the signal amplitude within that segment; Index for the time segment; This indicates the total number of data points contained within a time segment. For the index of the data points, This represents the arithmetic mean of the vibration signal amplitudes at all data points within a time interval. Indicates the first vibration signal amplitude at each data point By iterating through all time segments, the top 5% of time segments with the smallest standard deviation are selected as stable segments without significant fluctuations. The preset vibration amplitude range is determined based on the amplitude statistics of historical vertical vibration acceleration signals under normal conditions of the ballastless track of the operating line.

[0025] Step S2, by preprocessing the vertical vibration acceleration signal segment to remove anomalous pulse signals and constant baseline drift, significantly improves the validity and accuracy of the data. The identification and repair of anomalous pulse signals ensures signal integrity and avoids interference from sudden anomalous signals in subsequent analysis; the removal of constant baseline drift eliminates fixed offsets in the signal, making the signal more realistically reflect the joint vibration characteristics. This step provides high-quality signal samples for subsequent feature extraction.

[0026] Compared to existing technologies, this step innovatively combines anomalous pulse signal identification and constant baseline drift removal, enabling more accurate identification and correction of interference components in the signal. Traditional methods often ignore local anomalies or fixed drifts in the signal, leading to significant errors in the analysis results. However, by interpolating to repair anomalous signals and performing offset-free processing, the signal quality and consistency are greatly improved, laying a more reliable foundation for subsequent analysis.

[0027] Step S2 plays a key role in signal optimization throughout the scheme, ensuring the accuracy and stability of subsequent vibration feature parameter extraction by removing data interference and improving signal quality. At the same time, this step can reduce the misjudgment rate and improve the reliability of joint performance degradation evaluation, thereby providing necessary data support for accurately judging the state of the track joint and playing an important role in promoting comprehensive and accurate degradation monitoring.

[0028] S3: Feature extraction is performed on the joint vibration event sample to obtain a feature parameter set for representing the mechanical properties of the track joint, which includes a vibration frequency feature parameter reflecting joint stiffness degradation and a vibration attenuation feature parameter reflecting joint damping; In this embodiment, the specific execution process of S3 is as follows: The Fourier transform is used to perform frequency domain analysis on the joint vibration time sample to obtain a frequency domain signal The formula used is as follows: ; In the formula, is the joint vibration time sample, which is a time series signal; is the frequency; is the imaginary unit; is the constant pi; is the time variable; is the natural constant; Based on the frequency domain signal The power spectral density is calculated, and the calculation formula is as follows: ; In the formula, is the power spectral density corresponding to the th frequency component, which is used to reflect the vibration energy distribution of the frequency component, is the index of the frequency component; represents the th frequency domain component after Fourier transform; is the fixed sampling frequency of the acceleration sensor; is the total number of points of the joint vibration time sample, which is obtained by counting the number of signal points in the sample.

[0029] The dependent variable power spectral density is a physical quantity that specifically reflects the energy distribution intensity of the vibration signal at the th frequency component. Its technical significance lies in converting the time domain vibration signal into frequency energy distribution, thereby clearly revealing the contribution size of different frequency components in the signal. By identifying The peak value of the curve and its corresponding frequency can accurately locate the dominant vibration frequency of the joint structure, which is a key indicator to characterize the joint stiffness state. The PSD graph provides an intuitive and effective tool for diagnosing the joint structure characteristics from the energy perspective.

[0030] In the power spectral density curve , the frequency component that maximizes the value is identified and extracted , which is the main peak frequency, used to directly reflect the joint stiffness characteristics: when the joint stiffness decreases, it will shift to low frequency direction; define the frequency shift as the vibration frequency characteristic parameter, its calculation formula is as follows: ; In the formula, is the frequency shift, which is used to quantify the degree of joint stiffness degradation; is the reference main peak frequency in the preset joint performance reference parameter set, which is determined according to the historical data statistics under the normal state of the line.

[0031] The time domain analysis method is used to analyze the attenuation characteristics of the joint vibration event sample, and the damping variation characteristics of the track joint are extracted, the specific steps are as follows: The Hilbert transform is used to extract the vibration envelope of the joint vibration event sample : ; In the formula, is the vibration envelope, which is used to characterize the change trend of signal vibration amplitude with time; is the joint vibration time sample, is the Hilbert transform of ; is the value of the joint vibration time sample at time , is the integral variable.

[0032] The core significance of using Hilbert transform to extract the vibration envelope is to convert the complex oscillation signal into a smooth envelope line that can clearly characterize the overall trend of its amplitude change with time. This envelope line strips the details of high-frequency oscillation and highlights the overall energy decay process, providing essential input data for subsequent quantitative analysis of signal attenuation characteristics. This step upgrades the time domain analysis from observing the oscillation waveform to quantifying the energy decay law, which is an indispensable technical link for accurately evaluating the joint damping performance.

[0033] Vibration envelope Exponential fitting is performed to obtain signal attenuation rate , and the signal attenuation rate is defined as the vibration attenuation characteristic parameter; The formula for calculation is as follows: ; , wherein, is the initial amplitude, is the signal attenuation rate, which is used to represent the speed of vibration energy dissipation of the joint structure, i.e., its damping characteristics. Its technical significance lies in quantifying the internal friction, microscopic crack propagation, and structural connection state of the joint material, etc. hidden damage: An abnormal increase in the value usually indicates that the internal damage of the joint, such as fragmentation and increased friction, leads to accelerated energy dissipation; while An abnormal decrease in the value may indicate that the material is aging, elastic failure or off-joint, leading to a decrease in energy dissipation capacity. This parameter provides a key indicator for evaluating the internal state change of the joint material and can effectively identify early hidden damage; is the system natural frequency; is the time variable; The frequency offset and the signal attenuation rate are integrated to form a characteristic parameter set for representing the mechanical properties of the track joint.

[0034] Step S3 establishes a characteristic parameter set that can quantify the mechanical properties of the track joint by extracting features from the joint vibration event samples, including vibration frequency characteristic parameters and vibration attenuation characteristic parameters. This approach can directly capture the dynamic changes of the physical properties of the joint structure, provide quantitative and interpretable evaluation indicators, and has high sensitivity and reliability. Compared with directly relying on the original signal, extracting characteristic parameters can more effectively reduce noise interference and improve evaluation accuracy.

[0035] The prior art usually relies on experience or a single indicator to determine the joint state, which may result in insufficient evaluation accuracy of the deterioration. However, this step can more deeply reveal the change law of the joint stiffness and damping by comprehensively extracting two types of key parameters, i.e., vibration frequency and attenuation characteristics. Especially by extracting the main peak frequency through Fourier transform and calculating the frequency offset, combined with Hilbert transform analysis of vibration attenuation, precise identification and hierarchical evaluation of different deterioration modes can be achieved. This fusion of frequency domain and time domain features greatly improves the comprehensiveness and accuracy of diagnosis.

[0036] Step S3, as the core step of the whole monitoring scheme, converts the preprocessed vibration signal into a set of characteristic parameters that can comprehensively characterize the mechanical properties of the joint. This provides a high-quality data basis for the subsequent performance evaluation index calculation, ensuring that the evaluation results have higher credibility and interpretability. At the same time, the feature extraction means of this step lays the necessary technical foundation for the realization of automated and intelligent joint state evaluation, thereby further improving the efficiency and accuracy of joint degradation monitoring.

[0037] S4: Based on the vibration frequency characteristic parameters, vibration attenuation characteristic parameters and static force parameters, determine the joint performance evaluation index, compare the joint performance evaluation index with the preset evaluation threshold, based on the comparison result, determine the degradation level of the monitored track joint, and trigger the corresponding warning signal, the warning signal contains the degradation level of the monitored track joint and the position information of the joint; In this embodiment, based on the vibration frequency characteristic parameters, vibration attenuation characteristic parameters and static force parameters after dimensionless processing, the joint performance evaluation index is determined, and the formula is as follows: ; In the formula, is the joint performance evaluation index, which is used to reflect the degradation degree of the performance of the monitored jointless track joint; is the signal attenuation rate, is the signal attenuation rate reference value; is the frequency offset; 、 and is the preset weight, ， ， ， and 、 、 determined according to the analytic hierarchy process; is the static force parameter, is the index of the static force parameter, corresponding to temperature, pressure and pre-tightening force respectively, is the ideal value corresponding to the static force parameter.

[0038] The above formula sets the weight based on the engineering judgment of the main causes of jointless track joint degradation. The maximum weight is allocated to the frequency offset is the most direct and core representation of structural deterioration, and has the most significant impact on driving safety. The weight of the signal attenuation term is second, because it can effectively reflect the changes in material internal damage and damping characteristics, and is an important supplement to stiffness degradation. The total weight of static parameters is relatively low, because the environmental load factors such as temperature and pressure have large fluctuations and are usually a slow changing process. Although the abnormality of a single parameter needs to be concerned, it usually does not immediately cause serious structural safety problems like the sudden change of dynamic characteristics. This weight distribution reflects the comprehensive evaluation concept of "giving priority to dynamic parameters reflecting the internal state of the structure, and supplementing environmental and load state parameters", ensuring the sensitivity of the monitoring system to the core structural damage.

[0039] In the above formula, the dependent variable is the overall performance degradation index of the joint. The technical significance of the formula is to integrate the dynamic characteristics (stiffness and damping) and static state (temperature, pressure, and pre-tightening force) of the joint, normalize multiple heterogeneous parameters into a single evaluation index through mathematical modeling, and thus realize quantitative evaluation and graded early warning of the joint health condition.

[0040] The formula includes independent variables such as vibration frequency characteristic parameters , vibration attenuation characteristic parameters , and static parameter deviation terms . The correlation between these independent variables and the dependent variable is due to their direct association with the core performance of the joint: reflects the stiffness degradation of the joint, reflects the damping performance degradation, and the static parameter deviation terms reflect the temperature stress anomaly, load transfer capacity decline, and constraint failure, respectively. The independent variables affect through the superposition of their respective weights, and together form a multi-dimensional evidence chain of joint degradation, ensuring that can respond to the whole process from slight damage to severe degradation of the joint.

[0041] An increase in , an increase in , and an expansion of the static parameter deviation (i.e., temperature, pressure, and pre-tightening force deviating from the ideal state) will all cause the value of to rise, indicating that the performance degradation of the joint is intensifying. The square term in the formula strengthens the contribution of significant deviations, while the logarithmic function avoids the sensitivity of linear growth, making both sensitive to changes and maintaining numerical stability.

[0042] The formula has significant form rationality, and its structure design fully considers the practicability of multi-physical quantity fusion and engineering application. The main body of the formula is composed of two parts: the first part is obtained by taking the square root and logarithmic transformation of the linear combination of the frequency offset and the signal attenuation rate deviation, effectively fusing the dynamic characteristic parameters of the joint, and the nonlinear transformation not only ensures the smoothness of the output value, but also amplifies the sensitivity in the small signal change area; the second part adopts the square sum form of the relative deviation of the static force parameters, which significantly increases the weight of abnormal values in the comprehensive evaluation, and plays a role in strengthening the early warning. The two parts are organically combined by weighted summation, and the overall function is continuous, derivable and monotonically increasing, which ensures that there is a clear and interpretable positive correlation between the input parameters and the joint performance evaluation index, which meets the intuitive physical meaning of "the more serious the deterioration, the higher the index value", and provides a reliable mathematical basis for engineering decision-making.

[0043] Table 1: Joint performance evaluation index statistical table

[0044] Please refer to Figures 3-4 , it should be noted that the frequency offset, signal attenuation rate, temperature, pressure, pre-tightening force, and joint performance evaluation index in the above table 1 correspond to , , , , , in the above formula respectively; Through comprehensive analysis of the simulation data, it can be clearly observed that there is a significant positive correlation between the joint performance evaluation index and each monitoring parameter. As the frequency offset, signal attenuation rate deviation and each static force parameter deviate from their reference values, the SPEI value presents a clear upward trend. This shows that the structural stiffness, damping characteristics of the joint and its mechanical environment state jointly determine the degree of deterioration of its overall performance. The data clearly shows the continuous change process of the joint state from normal, slight deterioration to moderate and severe deterioration.

[0045] The contribution of each parameter to the SPEI value is not a simple linear superposition, but is fused through a specific nonlinear function. Among them, the frequency offset and signal attenuation rate constitute the basis of the evaluation, while the static force parameters are important correction terms, further reflecting the additional impact of environmental load and long-term stress state anomalies on the joint performance. This comprehensive evaluation method can more comprehensively capture the performance state of the joint under the action of multiple factors, avoiding the limitations of single index criterion.

[0046] The overall data trend shows that the evaluation formula can effectively distinguish the joint state with different degrees of deterioration, with good sensitivity and monotonicity. The distribution of SPEI value provides a reliable basis for setting multi-level warning thresholds, which can be used to realize accurate grading warning from "normal" to "severe deterioration", and provide quantitative support for preventive maintenance decision of ballastless track.

[0047] The joint performance evaluation index is established by integrating the vibration frequency characteristic parameter, the vibration attenuation characteristic parameter and the static force parameter. The deterioration level of the monitored track joint is determined by comparing the joint performance evaluation index with the preset evaluation threshold value: If , it is judged that the performance level of the monitored track joint is normal. If , it is judged that the performance level of the monitored track joint is slight deterioration. If , it is judged that the performance level of the monitored track joint is moderate deterioration. If , it is judged that the performance level of the monitored track joint is severe deterioration. In the formula, , and are respectively the first evaluation threshold value, the second evaluation threshold value and the third evaluation threshold value, which are determined according to statistical analysis of historical normal data and deterioration data. According to the above comparison method, the deterioration level of the monitored track joint is determined, and the corresponding warning signal is triggered, which includes the deterioration level of the monitored track joint and the position information of the joint.

[0048] Step S4 establishes a joint performance evaluation index by integrating the vibration frequency characteristic parameter, the vibration attenuation characteristic parameter and the static force parameter, and compares it with the preset evaluation threshold value to determine the deterioration level. The advantage of this step is that it can quantitatively integrate multi-dimensional parameters to provide a comprehensive evaluation of the joint performance, and divide the deterioration level through explicit evaluation threshold value, output intuitive and operable results, and trigger warning signals to feedback the health status and position information of the joint. This method is comprehensive and accurate, and is convenient for actual maintenance and decision-making.

[0049] Compared with the prior art, step S4 integrates vibration frequency, attenuation characteristics and static force parameters through dimensionless processing and weight distribution, overcoming the limitations of traditional methods relying on single parameters, significantly improving the accuracy and reliability of evaluation. In addition, the prior art usually lacks detailed classification of deterioration levels, while this step accurately divides different deterioration levels by defining multiple evaluation thresholds, thereby realizing grading diagnosis and efficient warning of joint state, with stronger practicality and operability.

[0050] In the present scheme, step S4 is the core link to realize the track joint state evaluation. It generates a clear and quantitative evaluation result by comprehensively analyzing the feature parameters and static parameters extracted in the previous steps, providing a scientific basis for the judgment of the deterioration state, maintenance decision and risk warning. At the same time, the output of the deterioration grade and the warning signal makes the whole monitoring scheme more instructive and practical, significantly improving the intelligent level and field application effect of the track joint monitoring.

[0051] Please refer to Figure 2 A ballastless track joint performance deterioration monitoring system, comprising: A data acquisition module for generating an excitation by knocking the ballastless track slab at the monitored ballastless track joint with a force hammer, collecting the vertical vibration acceleration response signal of the joint caused by the excitation using an acceleration sensor fixedly installed on the corresponding base structure of the joint, recording the knocking time, and obtaining a vertical vibration acceleration signal segment associated with the joint; simultaneously collecting the static parameters of the joint, including temperature, pressure and pre-tightening force; A data processing module for pre-processing the vertical vibration acceleration signal segment, removing abnormal pulse signals and constant baseline drift in the data, and obtaining a joint vibration event sample; the abnormal pulse signal is a transient signal exceeding the preset vibration amplitude range, and the constant baseline drift is a fixed offset existing in the data; A vibration feature extraction module for extracting features from the joint vibration event sample to obtain a feature parameter set for characterizing the mechanical properties of the track joint, the feature parameter set including a vibration frequency feature parameter reflecting the stiffness degradation of the joint and a vibration attenuation feature parameter reflecting the damping of the joint; A joint performance evaluation module for determining a joint performance evaluation index based on the vibration frequency feature parameter, the vibration attenuation feature parameter and the static parameter, comparing the joint performance evaluation index with a preset evaluation threshold, determining the deterioration grade of the monitored track joint based on the comparison result, and triggering a corresponding warning signal, the warning signal including the deterioration grade of the monitored track joint and the location information of the joint.

[0052] The above formulas are dimensionless numerical calculations, the formulas are obtained by software simulation of a large amount of data to obtain a formula of the most recent real situation, and the preset parameters in the formula are set by a person skilled in the art according to the actual situation.

[0053] The above-described embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the above-described embodiments can be implemented in whole or in part in the form of a computer program product. A person of ordinary skill in the art can be aware that units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on the specific application and design constraints of the technical solutions.

[0054] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, and can be located in one place or distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0055] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method of monitoring the performance deterioration of a ballastless track joint, characterized in that, The specific steps include: S1: By knocking the ballastless track slab at the joint to be monitored to generate an excitation, using an acceleration sensor fixedly installed on the base structure corresponding to the joint, collecting the vertical vibration acceleration response signal caused by the excitation, recording the time of knocking, and obtaining a vertical vibration acceleration signal segment associated with the joint; simultaneously collecting the static force parameters at the joint, including temperature, pressure and pretightening force; S2: Preprocessing the vertical vibration acceleration signal segment to remove abnormal pulse signals and constant baseline drift in the data, and obtaining a joint vibration event sample; the abnormal pulse signal is a transient signal exceeding the preset vibration amplitude range, and the constant baseline drift is a fixed offset continuously existing in the data; S3: Feature extraction is performed on the joint vibration event sample to obtain a feature parameter set for characterizing the mechanical properties of the track joint, the feature parameter set including a vibration frequency feature parameter reflecting joint stiffness degradation and a vibration attenuation feature parameter reflecting joint damping; S4: Based on the vibration frequency feature parameter, the vibration attenuation feature parameter and the static force parameter, a joint performance evaluation index is determined, the joint performance evaluation index is compared with a preset evaluation threshold, based on the comparison result, the degradation level of the track joint to be monitored is determined, and a corresponding warning signal is triggered, the warning signal including the degradation level of the track joint to be monitored and the position information of the joint.

2. The method for monitoring the performance deterioration of a ballastless track joint according to claim 1, characterized in that: In S1, the base structure includes: a track slab bearing platform, a trackside cable trough inner wall or a box girder top; For longitudinal joints between track slabs, the acceleration sensor is fixed to the side of the track slab bearing platform on both sides of the joint, 0.3-0.5m away from the edge of the joint; for transverse joints, the sensor is installed on the inner wall of the trackside cable trough near the joint or the top of the box girder directly below the joint; the sensor is connected to the base structure through a stainless steel bracket; The temperature sensor, pressure sensor and pretightening force sensor are pre-buried in the joint or tension lock during the track slab width joint treatment construction, respectively used for collecting temperature, pressure and pretightening force data at the joint; A standard hammer with a force sensor on the hammer head is used to vertically knock the ballastless track slab at 1-2 fastener spacings closest to the joint to be monitored, the force sensor is used to monitor the knocking force in real time, and the feedback device is used to ensure that the peak impact force of a single knock is stable within the preset rated range, so as to generate a standard excitation with consistent energy; at the same time, an acceleration sensor is used to collect the vibration response at the joint to be monitored in real time, and a fixed time length of signal is continuously recorded at a sampling frequency of no less than 10kHz, so as to ensure that the whole process waveform from the beginning of the excitation, vibration transmission to complete vibration attenuation is completely captured, and finally a complete vertical vibration acceleration signal segment strictly corresponding to this standard knocking excitation is obtained, and the static force parameters at the joint are simultaneously collected, including temperature, pressure and pretightening force.

3. The method for monitoring the performance deterioration of a ballastless track joint according to claim 2, characterized in that: The abnormal pulse signal identification is performed on the vertical vibration acceleration signal segment, a preset vibration amplitude range is set, a point-by-point traversal method is used to scan the vertical vibration acceleration signal segment, when it is detected that the amplitude of a signal point exceeds the preset vibration amplitude range, it is determined that the signal point and adjacent signal points which are continuous with the signal point and have amplitudes exceeding the range constitute an abnormal pulse signal; For the identified abnormal pulse signals, an interpolation completion method is used for processing, using the closest pulse signal to the abnormal pulse signal. Based on the mean of normal signal points, the complete data corresponding to the abnormal pulse signal is calculated by linear interpolation and replaced with the original abnormal pulse signal data. The constant baseline drift identification is performed on the vertical vibration acceleration signal after the abnormal pulse signal is removed, a smooth section without obvious vibration fluctuation in the signal is selected, the mean value of all signal points in the smooth section is calculated, and the mean value is taken as the constant baseline drift amount; the constant baseline drift is removed by subtracting the constant baseline drift amount from the value of each signal point in the entire vertical vibration acceleration signal segment, and a joint vibration event sample is obtained; The determination method of the smooth section is that the complete vertical vibration acceleration signal segment is divided into a plurality of equal-length time sub-sections, and the standard deviation of the vibration signal amplitude of each time sub-section is calculated according to the following formula: ； In the formula, Indicates the first The standard deviation of the vibration signal amplitude for each time segment is used to quantify the degree of fluctuation in the signal amplitude within that segment. Index for the time segment; This indicates the total number of data points contained within a time segment. For the index of the data points, This represents the arithmetic mean of the vibration signal amplitudes at all data points within a time interval. Indicates the first vibration signal amplitude at each data point All time sub-sections are traversed, and the first 5% of the time sub-sections with the smallest standard deviation are selected as the smooth section without obvious vibration fluctuation; The preset vibration amplitude range is determined based on the amplitude statistical result of the historical vertical vibration acceleration signal under the normal state of the operating line ballastless track.

4. The method for monitoring the performance deterioration of a ballastless track joint according to claim 1, characterized in that: The specific execution process of S3 is as follows: The time sample of joint vibration is analyzed in frequency domain by Fourier transform, and the frequency domain signal is obtained The formula is as follows: ； wherein is the joint vibration time sample, which is a time series signal; is the frequency; is the imaginary unit; is the mathematical constant pi; is the time variable; is the mathematical constant e. Frequency domain signal The power spectral density is calculated as follows: ； In the formula, is the power spectral density corresponding to the th frequency component, used to reflect the vibration energy distribution of the frequency component, is the index of the frequency component; represents the th frequency domain component after Fourier transform; is the fixed sampling frequency of the acceleration sensor; is the total number of points of the joint vibration time sample, obtained by counting the number of signal points in the sample; In the power spectral density curve , the frequency component that makes the value maximum is identified and extracted , , that is, the main peak frequency, is used to directly reflect the joint stiffness characteristics: when the joint stiffness decreases, , it will shift to low frequency direction; the frequency shift is defined as the vibration frequency characteristic parameter, and its calculation formula is as follows: ； In the formula, is a frequency offset, used to quantify the degree of joint stiffness degradation; is a reference main peak frequency in the preset joint performance reference parameter set, determined according to historical data statistics under a normal state of the line.

5. The method for monitoring the performance deterioration of a ballastless track joint according to claim 4, characterized in that: The attenuation characteristics of the joint vibration event sample are analyzed by using a time domain analysis method, and the damping variation characteristics of the track joint are extracted, and the specific steps are as follows: Extracting a vibration envelope of a joint vibration event sample using a Hilbert transform : ； wherein is the vibration envelope, used to characterize the trend of the signal vibration amplitude over time; is the joint vibration time sample, is the Hilbert transform of is the mathematical constant pi; denotes the value of the joint vibration time sample at time , is the integration variable; to the vibration envelope An exponential fit is performed to obtain a signal decay rate and the signal decay rate is defined as a vibration decay characteristic parameter; The formula for calculation is as follows: ； wherein is the initial amplitude, is the signal decay rate, used to characterize the change in joint damping performance; is the system natural frequency; is the time variable; The frequency offset amount And signal attenuation rate Integration, constitute a set of characteristic parameters for characterization of track joint mechanical properties.

6. The method for monitoring the performance deterioration of a ballastless track joint according to claim 5, characterized in that: Based on the dimensionless vibration frequency characteristic parameter, the vibration attenuation characteristic parameter and the static force parameter, a joint performance evaluation index is determined, and the formula is as follows: ； In the formula, is a joint performance evaluation index, used to reflect the degree of deterioration of the joint performance of the monitored ballastless track; is a signal attenuation rate, is a signal attenuation rate reference value; is a frequency offset amount; , and are preset weights; is a static force parameter, is an index of the static force parameter, respectively correspond to temperature, pressure and pre-tightening force, is an ideal value corresponding to the static force parameter.

7. The method for monitoring the performance deterioration of a ballastless track joint according to claim 6, characterized in that: said joint performance evaluation index comparing the joint performance evaluation index with a pre-set evaluation threshold, determining a deterioration level of the track joint to be monitored: If then the track joint performance level to be monitored is determined to be: normal; If then the track joint performance level to be monitored is determined to be: slight deterioration; If then the performance level of the track joint to be monitored is determined to be: moderate deterioration; If then the performance level of the track joint to be monitored is determined to be: severe deterioration; In the formula, , and are respectively preset first evaluation threshold, second evaluation threshold and third evaluation threshold, which are determined according to statistical analysis of historical normal data and degradation data. According to the above comparison method, the degradation level of the to-be-monitored track joint is determined, and a corresponding early warning signal is triggered, and the early warning signal includes the degradation level of the to-be-monitored track joint and the position information of the joint.

8. A system for monitoring performance degradation of a ballastless track joint, the system comprising: The ballastless track joint performance degradation monitoring system is used to execute the ballastless track joint performance degradation monitoring method of any one of claims 1-7, and includes: The data acquisition module is used to generate an excitation by knocking the ballastless track at the to-be-monitored ballastless track joint by using a force hammer, collect a joint vertical vibration acceleration response signal caused by the excitation by using an acceleration sensor fixedly installed on the base structure corresponding to the joint, record a knocking time, and obtain a vertical vibration acceleration signal segment associated with the joint; and simultaneously collect static force parameters of the joint, including temperature, pressure and pre-tightening force; The data processing module is used to pre-process the vertical vibration acceleration signal segment, remove abnormal pulse signals and constant baseline drift in the data, and obtain a joint vibration event sample; the abnormal pulse signal is a transient signal exceeding a preset vibration amplitude range, and the constant baseline drift is a fixed offset existing in the data; The vibration characteristic extraction module is used to extract characteristics of the joint vibration event sample, obtain a characteristic parameter set for representing the mechanical performance of the track joint, and the characteristic parameter set includes a vibration frequency characteristic parameter reflecting joint stiffness degradation and a vibration attenuation characteristic parameter reflecting joint damping; The joint performance evaluation module determines a joint performance evaluation index based on the vibration frequency characteristic parameter, the vibration attenuation characteristic parameter and the static force parameter, compares the joint performance evaluation index with a preset evaluation threshold, determines a deterioration level of the to-be-monitored track joint based on a comparison result, and triggers a corresponding early warning signal, wherein the early warning signal includes the deterioration level of the to-be-monitored track joint and position information of the joint.

Images