Tunnel vehicle-induced pressure wave refined generation device based on short-time Fourier transform

Abstract

The invention relates to the field of high-speed railway tunnel aerodynamics, in particular to a tunnel train-induced pressure wave refined generation device based on short-time Fourier transform, a positive and negative pressure generation module is used for generating positive pressure waves and negative pressure waves generated when a high-speed train passes through a tunnel; the central control module is connected with the positive and negative pressure generation module, and the central control module is used for generating pressure waves with the same frequency as the tunnel field transient pressure waves and controlling the generation frequency, intensity and duration of the pressure waves through a short-time Fourier transform program; and the pressure wave output module is connected with the central control module and is used for outputting the generated positive pressure wave and negative pressure wave to a target test model. The system has the advantages of being high in automation degree, high in adaptability and wide in practicability, accurate simulation can be conducted according to different tunnel structures and working conditions, and scientific support is provided for tunnel design and train operation safety.

Description

Technical Field

[0001] The invention relates to the field of aerodynamics of high-speed railway tunnels, in particular to a device for generating refined tunnel vehicle-induced pressure waves based on short-time Fourier transform. Background Art

[0002] As the design speed of my country's high-speed railways increases day by day, the pressure wave effect generated by train driving in tunnels is gradually intensifying. The pressure wave in the tunnel refers to a series of pressure change phenomena caused by the interaction of air between the train and the tunnel wall when the high-speed train enters the tunnel. This pressure change propagates in the tunnel in the form of waves, usually including positive pressure waves and negative pressure waves. Positive pressure waves occur at the moment the train enters the tunnel, and the compression of the air by the head of the train causes the air pressure at the entrance of the tunnel to increase; while negative pressure waves occur when the train leaves the tunnel, and the expansion of the air by the tail of the train causes the air pressure at the exit of the tunnel to decrease. The impact of pressure waves is mainly reflected in the safety of train operation, the stability of the tunnel lining structure, the safety of tunnel ancillary structures, environmental impact, train energy consumption and passenger comfort.

[0003] Due to the difficulty, high cost and poor repeatability of field testing, experimental methods are usually used to study the impact of pressure waves in high-speed railway tunnels on tunnel structures, passengers and the surrounding environment. The accurate simulation and use of pressure waves in the test can better predict and evaluate the stress conditions of the tunnel structure in actual operation, thereby optimizing the design of tunnels, ancillary facilities or train structures, and improving structural safety and durability. Traditional test methods use harmonics or rectangular waves to simulate pressure waves in tunnels. Such methods often cannot accurately capture and simulate dynamically changing pressure wave phenomena in real time, which limits the in-depth understanding and effective control of complex airflow behavior in tunnels. Summary of the invention

[0004] The method of the present invention analyzes the time-frequency characteristics of the input data in a short time and dynamically adjusts the working state of the pressure wave output module, and proposes a tunnel vehicle-induced pressure wave refinement generation device based on short-time Fourier transform to simulate pressure waves under different speeds, different train types and different tunnel conditions, and can complete more refined and more types of pressure wave tests in a short time.

[0005] In order to achieve the above objectives, the following technical solutions are proposed:

[0006] A tunnel vehicle-induced pressure wave refinement generating device based on short-time Fourier transform comprises a positive and negative pressure generating module, a central control module and a pressure wave output module.

[0007] The positive and negative pressure generating module is used to generate positive pressure waves and negative pressure waves generated when simulating a high-speed train passing through a tunnel;

[0008] The central control module is connected to the positive and negative pressure generating module, and is used to generate a pressure wave with the same frequency as the transient pressure wave at the tunnel site, and to control the generation frequency, intensity and duration of the pressure wave through a short-time Fourier transform program;

[0009] The pressure wave output module is connected to the central control module and is used to output the generated positive pressure waves and negative pressure waves to the target test model.

[0010] Preferably, the positive and negative pressure generating module comprises an air compressor and a vacuum machine, wherein the air compressor generates positive pressure waves and the vacuum machine generates negative pressure waves;

[0011] By adjusting the output pressure of the air compressor and the suction rate of the vacuum machine, the required positive pressure waveform and negative pressure waveform are generated respectively;

[0012] The air compressor and vacuum machine work together to simulate the pressure changes when a high-speed train passes through a tunnel.

[0013] Preferably, the positive pressure wave and the negative pressure wave are transmitted to the target test model by a pressure waveguide in the pressure wave output module.

[0014] Preferably, the pressure wave output module further includes a pressure sensor for monitoring the transmission state and intensity of the pressure wave.

[0015] Preferably, the central control module comprises a microprocessor for receiving input measured pressure wave data and analyzing pressure wave time-frequency data in real time.

[0016] Preferably, the short-time Fourier transform program adopts short-time Fourier transform, and adopts an adaptive window function to segment according to the length of the initial compression wave, and each segment of data has a specified overlapping length.

[0017] Preferably, the formula for the short-time Fourier transform of the pressure wave is:

[0018]

[0019] Among them, P(t) is the pressure wave signal, P(τ) is the original signal, t is the time, e -jωt is a complex function, ω is the angular frequency, and w(t-τ) is the window function.

[0020] Compared with the prior art, the present invention has the following advantages: the present invention can analyze the time-frequency characteristics of the input data in a short time and dynamically adjust the working state of the pressure wave output module to simulate pressure waves under different speeds, different train types and different tunnel conditions, and can complete more refined and more types of pressure wave tests in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a connection diagram of the device for refining the tunnel vehicle-induced pressure wave based on short-time Fourier transform in Example 1;

[0022] Figure 2 It is a flowchart of a specific method for using the device for refining the vehicle-induced pressure wave in a high-speed railway tunnel based on short-time Fourier transform in Example 1;

[0023] Figure 3 is a schematic diagram of the operation of the short-time Fourier transform program in Example 1;

[0024] Figure 4 It is a schematic diagram of a specific embodiment of the device for refining the vehicle-induced pressure wave in a high-speed railway tunnel based on short-time Fourier transform in Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0026] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0027] Example 1

[0028] A device for refining tunnel vehicle-induced pressure waves based on short-time Fourier transform, such as Figure 1 As shown, it includes a positive and negative pressure generating module, a central control module and a pressure wave output module.

[0029] The positive and negative pressure generating module is used to generate positive pressure waves and negative pressure waves generated when simulating a high-speed train passing through a tunnel;

[0030] The central control module is connected to the positive and negative pressure generating module, and is used to generate a pressure wave with the same frequency as the transient pressure wave at the tunnel site, and to control the generation frequency, intensity and duration of the pressure wave through a short-time Fourier transform program;

[0031] The pressure wave output module is connected to the central control module and is used to output the generated positive pressure waves and negative pressure waves to the target test model.

[0032] The present invention aims to provide a device that can accurately simulate the pressure wave caused by the vehicle in the high-speed railway tunnel in the test, and can repeatedly output the pressure wave of the high-speed railway tunnel in a cycle to analyze the stress characteristics of the structure under the action of the cyclic pressure wave, so as to improve the efficiency and accuracy of the aerodynamic test research of the high-speed railway tunnel. The device is based on the short-time Fourier transform technology, and integrates the positive and negative pressure generation module, the central control module, the pressure wave output module and the target test model. The target test model may include but is not limited to: tunnel lining structure, train structure and tunnel ancillary facilities. The positive and negative pressure generation module generates pressure waves when simulating the train passing through the tunnel through the coordinated work of the air compressor and the vacuum machine; the central control module has a built-in short-time Fourier transform program to accurately control the frequency, intensity and duration of the pressure wave; the pressure wave output module is responsible for transmitting the simulated pressure wave to the target test model, which is used to simulate the stress state of the tunnel lining, train or distribution box and other ancillary facilities under the influence of the pressure wave. The present invention realizes rapid processing and precise control of pressure wave data through real-time short-time Fourier transform analysis, thereby improving the automation and intelligence level of the test; the self-developed algorithm combines actual on-site data for regression analysis, so that the device can adapt to a variety of tunnel-related structures and working conditions, and has wide applicability and high practicality.

[0033] As a specific embodiment, test preparation: Before the test begins, the various components of the equipment need to be connected, and the connection method is as follows: Figure 2 First, prepare the field test pressure wave data according to the actual parameters such as the length of the high-speed railway tunnel, the design speed and the actual operating speed, and prepare to input it into the microprocessor; prepare the positive and negative pressure generation module, the central control module, the pressure wave output module and the target test model according to the specific environment and requirements of the high-speed railway tunnel; ensure that the size, material and performance of all modules and test models meet the design requirements.

[0034] Installation of positive and negative pressure generating modules: Install air compressors and vacuum machines at appropriate locations indoors to ensure that they can obtain stable power supply and are not interfered by irrelevant factors. By adjusting the output pressure of the air compressor and the suction rate of the vacuum machine, positive and negative pressure caused by train operation are generated.

[0035] Central control module setting: The central control module is connected near the positive and negative pressure generating module, including a microprocessor, a user interface and a short-time Fourier transform program. The microprocessor is responsible for receiving the measured pressure wave data input by the user, and the user interface is used to display the real-time data of the pressure wave and the system status.

[0036] Configuration of the pressure wave output module: connect the central control module with the pressure wave output module, including the installation of the pressure waveguide and pressure sensor. Built-in dynamic balance electric pressure regulating valve, the working pressure of the valve is Pa ~ 20000Pa level, by receiving the electrical signal (0-10V or 4-20MA) from the central control module to control the valve opening, so as to dynamically adjust the output pressure. The pressure waveguide is used to transmit the generated pressure wave to the target test model, and the pressure sensor is used to monitor the transmission status and intensity of the pressure wave.

[0037] Target test model layout: A simulated tunnel lining structure, train carriage structure or distribution box structure is installed at the output end of the pressure wave output module, and stress sensors and displacement sensors are installed on them to record and analyze the impact of pressure waves on these structures.

[0038] Short-time Fourier transform program operation: Start the short-time Fourier transform program in the central control module to perform real-time analysis on the pressure wave data input by the user to ensure the accuracy and consistency of the input and output pressure waves in frequency and amplitude. Figure 3 . Pressure wave signal p(t) The short-time Fourier transform of should be expressed as:

[0039]

[0040] Among them, P(t) is the pressure wave signal, P(τ) is the original signal, t is the time, e -jωt is a complex function, ω is the angular frequency, and w(t-τ) is the window function.

[0041] The short-time Fourier transform uses an adaptive window function to segment the pressure data input by the user. Each segment has a specified overlap length to reduce the spectrum leakage effect during the transformation process and improve the frequency resolution. The segment length is recommended to refer to the initial compression wave length. Figure 4 Taking the embodiment of as an example, the initial compression wave lasts for about 3 seconds, and it is recommended to set the segment length to about 3 seconds. At the same time, it can provide the frequency component of the pressure signal changing with time, while the standard Fourier transform can only provide the average frequency information within the entire signal time interval.

[0042] Pressure wave monitor installation: A pressure wave monitor is installed between the positive and negative pressure generating module and the pressure wave output module to further display the shape and characteristics of the pressure wave to better simulate the actual working conditions.

[0043] Test and debugging: Conduct a series of tests to simulate the pressure wave impact when trains pass through the tunnel at different speeds, as well as the response of the tunnel structure under different geological and environmental conditions. Adjust the parameters of each module according to the test results until the expected simulation effect is achieved. Specific implementation examples include Figure 4As shown. Figure 4 In the test, the user inputs the pressure wave time-history data obtained from the field test, the central control module analyzes the main frequency and amplitude of the pressure wave, and the positive and negative pressure generation module dynamically adjusts the amplitude of the pressure wave through the dynamic balance electric pressure regulating valve, and outputs a cyclic pressure wave load to the test model.

[0044] Through the above steps, the effective operation of the high-speed railway tunnel vehicle-induced pressure wave generating device based on short-time Fourier transform can be ensured, providing strong technical support for the safe operation and scientific research of high-speed railway tunnels.

[0045] Finally, it should be noted that the embodiments described in detail above are only the best practices of the invention and cannot be used to limit the scope of rights of the invention. Equivalent replacement of the technical solutions recorded in the aforementioned embodiments does not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the invention, and they should all be included in the scope of the claims and description of the invention.

Claims

1. A device for refining the tunnel vehicle-induced pressure wave based on short-time Fourier transform, characterized in that: It includes a positive and negative pressure generating module, a central control module and a pressure wave output module. The positive and negative pressure generating module is used to generate positive pressure waves and negative pressure waves generated when simulating a high-speed train passing through a tunnel; The central control module is connected to the positive and negative pressure generating module, and is used to generate a pressure wave with the same transient pressure wave frequency as that at the tunnel site, and to control the frequency, intensity and duration of the pressure wave through a short-time Fourier transform program; The pressure wave output module is connected to the central control module and is used to output the generated positive pressure waves and negative pressure waves to the target test model.

2. The device for generating vehicle-induced pressure waves in tunnels based on short-time Fourier transform according to claim 1, characterized in that: The positive and negative pressure generating module comprises an air compressor and a vacuum machine, wherein the air compressor generates positive pressure waves and the vacuum machine generates negative pressure waves; By adjusting the output pressure of the air compressor and the suction rate of the vacuum machine, the required positive pressure waveform and negative pressure waveform are generated respectively; The air compressor and vacuum machine work together to simulate the pressure changes when a high-speed train passes through a tunnel.

3. The device for generating fine-tuning tunnel vehicle-induced pressure waves based on short-time Fourier transform according to claim 2, characterized in that: The positive pressure wave and the negative pressure wave are transmitted to the target test model by the pressure wave guide tube in the pressure wave output module.

4. The device for generating vehicle-induced pressure waves in tunnels based on short-time Fourier transform according to claim 1, characterized in that: The pressure wave output module also includes a pressure sensor for monitoring the transmission state and intensity of the pressure wave.

5. The device for generating vehicle-induced pressure waves in tunnels based on short-time Fourier transform according to claim 1, characterized in that: The central control module includes a microprocessor for receiving input measured pressure wave data and analyzing the pressure wave time-frequency data in real time.

6. The device for generating fine-tuning tunnel vehicle-induced pressure waves based on short-time Fourier transform according to claim 5, characterized in that: The short-time Fourier transform program adopts short-time Fourier transform and uses an adaptive window function to segment according to the length of the initial compression wave, and each segment of data has a specified overlapping length.

7. The device for generating fine-tuning tunnel vehicle-induced pressure waves based on short-time Fourier transform according to claim 6, characterized in that: The formula for the short-time Fourier transform of the pressure wave is: Among them, P(t) is the pressure wave signal, P(τ) is the original signal, t is the time, e -jωt is a complex function, ω is the angular frequency, and w(t-τ) is the window function.

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