Tunnel sound absorption coefficient testing method and system during simulated train passing and storage medium

Abstract

The invention discloses a tunnel sound absorption coefficient testing method and system when a simulated train passes, and a storage medium. The method comprises the following steps: acquiring a sound signal data set based on a pulse sound source and a microphone array; processing the original signal data of each measuring point of the microphone array when there is no train or the train is located at different positions to obtain tunnel sound absorption coefficient values when there is no train or the train is located at different positions; fitting the sound absorption coefficient values of the tunnel when no train exists and the train is located at different positions by adopting a function fitting mode to obtain a tunnel sound absorption coefficient change curve when the simulated train passes; the method can further fit to obtain the tunnel sound absorption coefficient change curve when the simulated train passes through by testing the sound absorption coefficient values of the tunnel when no train exists and the train is located at different positions, and is high in test precision, low in cost, wide in application range and suitable for popularization and application. And the defect that an existing testing method cannot test the sound absorption coefficient when a train exists in the tunnel can be overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle noise testing, and in particular to a method, system and storage medium for testing the sound absorption coefficient of a tunnel when simulating a train passing through. Background Art

[0002] In recent years, with the rapid development of rail transit, noise pollution has gradually attracted widespread attention from all walks of life. The noise generated by trains running in tunnels is a complex issue. Due to the special structure of tunnels, the sound will produce a reverberation effect during the reflection, refraction and absorption process inside the tunnel, which will increase the noise level inside the car and affect the comfort and health of passengers.

[0003] The sound absorption coefficient of a tunnel is an indicator of the ability of the tunnel wall material to absorb sound. Materials with high sound absorption coefficients can effectively reduce the reflection and propagation of sound in the tunnel, thereby reducing the reverberation effect caused by trains passing through the tunnel. Therefore, when designing and treating tunnel train noise problems, choosing materials with appropriate sound absorption coefficients can effectively reduce noise levels and improve the acoustic environment of the tunnel, so the test of tunnel sound absorption coefficients is particularly important.

[0004] In order to obtain the actual sound absorption coefficient of the tunnel wall, the average reverberation time of each measuring point in the tunnel is tested to obtain one-third of the spectrum; the reverberation time is the time T60 required for the initial sound pressure level to decay by 60 dB after the sound source excitation stops; at present, the existing test method for the sound absorption coefficient of the tunnel cannot test the sound absorption coefficient of the train passing through the tunnel. The main reason is that under the premise of considering the train operation and the safety of the test personnel, the personnel usually enter the tunnel to work without a train, and the sound absorption coefficient of the empty tunnel without a train is tested; in addition, for the traditional test method of the sound absorption coefficient, if the actual train passing is used as the noise source, and sensors are arranged in the tunnel for synchronous collection while ensuring the normal operation of the train, the cost of sensor arrangement and safety control is greatly increased. At the same time, since the sound field of the sound source of the actual operation of the train is uneven and the sound pressure level is not constant during the whole process, it is difficult to determine the reverberation level therein, and the analysis results may have large errors and poor accuracy. Summary of the invention

[0005] The purpose of the present invention is to provide a method, system and storage medium for testing the sound absorption coefficient of a tunnel when a train is passing through. The method can further fit the change curve of the sound absorption coefficient of the tunnel when there is no train and when the train is at different positions, and the method has high testing accuracy, low cost and wide application range, and can make up for the deficiency of the existing testing method that the sound absorption coefficient cannot be tested when there is a train in the tunnel. To achieve the above purpose, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for testing the sound absorption coefficient of a tunnel when simulating a train passing through, comprising: S1: Acquire an acoustic signal data set based on a pulse sound source and a microphone array, wherein the acoustic signal data set includes original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions; S2: Processing the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, respectively, to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; wherein the processing process includes: Based on the original signal data of a certain measuring point of the microphone array when there is no train or the train is at a different position, the sampling frequency is adjusted to perform resampling to obtain new signal data; Perform filtering and conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Using Sabine's formula, according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is obtained; Based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, the tunnel sound absorption coefficient value when there is no train or the train is located at different positions is obtained; S3: Use function fitting to fit the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions, and obtain the tunnel sound absorption coefficient change curve when simulating the train passing.

[0006] Optionally, the acquiring of the acoustic signal dataset based on the pulse sound source and the microphone array includes: Arranging a microphone array and a pulse sound source in the tunnel; wherein the microphone array includes a plurality of microphone sensors in the same plane, the plane is parallel to the tunnel cross section, and each microphone sensor serves as a measuring point; When there is no train in the tunnel, the pulse sound source is played. After a stable sound field is formed, the pulse sound source is turned off. At this time, the microphone array is used to collect data and record the data for a period of time when it decays to the background noise level, so as to obtain the original signal data of each measuring point of the microphone array when there is no train. When the train stops at different positions in the tunnel, the pulse sound source is played respectively. After a stable sound field is formed, the pulse sound source is turned off, and data is collected using the microphone array. The data for the period of time when it decays to the background noise level is recorded, thereby obtaining the original signal data of each measuring point of the microphone array when the train is at different positions.

[0007] Optionally, the number of the microphone arrays is greater than 2 and is evenly distributed in the tunnel.

[0008] Optionally, the pulse sound source is placed at the center of the tunnel floor.

[0009] Optionally, the filtering and conversion processing is performed on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point, including: Filter the new signal data according to 1 / 3 octave to obtain filtered signal data; The filtered signal data is subjected to coordinate transformation processing to obtain a time domain signal; Take the logarithm of the amplitude of the time domain signal to obtain the peak point set; Based on the peak point set, find the starting point of decay and use it to intercept the decay interval data; Perform linear fitting on the decay interval data to obtain the attenuation slope of each 1 / 3 center frequency at a certain measurement point; Based on the attenuation slope of each 1 / 3 center frequency at a certain measuring point, calculate the reverberation time of each 1 / 3 center frequency at a certain measuring point.

[0010] Optionally, the formula for calculating the reverberation time of each 1 / 3 center frequency of a certain measurement point is as follows:

[0011] in, k Indicates the attenuation slope of a certain 1 / 3 center frequency; T 60 Indicates the reverberation time corresponding to the decay slope.

[0012] Optionally, the Sabine formula is used to obtain a one-third octave frequency spectrum of the sound absorption coefficient of a certain measuring point according to the reverberation time of each 1 / 3 center frequency of a certain measuring point, including: Get tunnel volume and tunnel area; The Sabin formula is used to calculate the sound absorption coefficient of each 1 / 3 center frequency at a certain measuring point according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the tunnel volume and the tunnel area; the Sabin formula is expressed as follows:

[0013] in, V represents the volume of the tunnel; s represents the area of ​​the tunnel; Indicates the sound absorption coefficient of a certain 1 / 3 center frequency; The sound absorption coefficients of each 1 / 3 center frequency of a certain measuring point are combined to obtain a one-third octave band spectrum of the sound absorption coefficient of a certain measuring point.

[0014] Optionally, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is used to obtain the tunnel sound absorption coefficient value when there is no train or the train is located at different positions, including: Based on the one-third octave band spectrum of the sound absorption coefficient of a certain measuring point, calculate the average value of the sound absorption coefficient of all 1 / 3 center frequencies of a certain measuring point to obtain the average sound absorption coefficient of a certain measuring point; The average sound absorption coefficient of all measuring points is obtained according to the above method, and then the average sound absorption coefficient of all measuring points is averaged to obtain the tunnel sound absorption coefficient value when there is no train or the train is located at different positions.

[0015] In a second aspect, the present invention provides a tunnel sound absorption coefficient testing system for simulating train passing, comprising: A data acquisition module, used for acquiring an acoustic signal data set based on a pulse sound source and a microphone array, wherein the acoustic signal data set includes original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions; A data processing module is used to process the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, so as to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; The processing process includes: Based on the original signal data of a certain measuring point of the microphone array when there is no train or the train is at a different position, the sampling frequency is adjusted to perform resampling to obtain new signal data; Perform filtering and conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Using Sabine's formula, according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is obtained; Based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, the tunnel sound absorption coefficient value when there is no train or the train is located at different positions is obtained; The data fitting module is used to fit the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions by using a function fitting method, so as to obtain a tunnel sound absorption coefficient variation curve when simulating the train passing through.

[0016] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for testing the sound absorption coefficient of a tunnel when simulating a train passing through as described in the first aspect.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method, system and storage medium for testing the sound absorption coefficient of a tunnel when a train is passing through. The testing method processes the original signal data of each measuring point of a microphone array when there is no train and when the train is at different positions, respectively, to obtain the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions; the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions are further fitted to obtain a tunnel sound absorption coefficient variation curve when a train is passing through, which can make up for the deficiency of the existing testing method that the sound absorption coefficient cannot be tested when there is a train in the tunnel, and the method has high testing accuracy, low cost and wide application range, and the sound absorption coefficient obtained by the method is used in noise prediction simulation, which is closer to the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor, among which: Figure 1 The figure is a schematic flow chart of a method for testing the sound absorption coefficient of a tunnel when simulating a train passing through an embodiment of the present invention; Figure 2 The figure shows a schematic diagram of the whole structure of microphone array in an embodiment of the present invention; Figure 3 Shown are schematic diagrams of the position of a train at different positions and sound sources in an embodiment of the present invention; Figure 4 Shown is a time domain diagram of original signal data in an embodiment of the present invention; Figure 5 Shown is a time domain diagram of signal data after resampling in an embodiment of the present invention; Figure 6 Shown is a Bode diagram of a filter in an embodiment of the present invention; Figure 7 The figure shows a schematic diagram of a time domain signal after filtering in an embodiment of the present invention; Figure 8 The figure shows a schematic diagram of the logarithm of the filtered time domain signal in an embodiment of the present invention; Fig. 9 Shown is a schematic diagram of a peak point set in an embodiment of the present invention; Fig.10 The figure shows a schematic diagram of decay interval data after linear fitting in an embodiment of the present invention; Fig.11 Shown is a schematic diagram of a curve showing a change in tunnel sound absorption coefficient when simulating a train passing through in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0020] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present disclosure. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0021] Example 1

[0022] refer to Figure 1 The embodiment of the present invention introduces a method for testing the sound absorption coefficient of a tunnel when simulating a train passing through, comprising the following steps: S1: Acquire an acoustic signal data set based on a pulse sound source and a microphone array, wherein the acoustic signal data set includes original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions; S2: Processing the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, respectively, to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; wherein the processing process includes: Based on the original signal data of a certain measuring point of the microphone array when there is no train or the train is at a different position, the sampling frequency is adjusted to perform resampling to obtain new signal data; Perform filtering and conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Using Sabine's formula, according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is obtained; Based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, the tunnel sound absorption coefficient value when there is no train or the train is located at different positions is obtained; S3: Use function fitting to fit the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions, and obtain the tunnel sound absorption coefficient change curve when simulating the train passing.

[0023] The present embodiment provides a method for testing the sound absorption coefficient of a tunnel when a simulated train passes through. The method can further fit the change curve of the sound absorption coefficient of the tunnel when a simulated train passes through by testing the sound absorption coefficient values ​​of the tunnel when there is no train and when the train is at different positions. The method has high testing accuracy, low cost, and a wide range of applications, and can make up for the deficiency of the existing testing method that it is impossible to test the sound absorption coefficient when there is a train in the tunnel.

[0024] In this embodiment, the step S1 of acquiring an acoustic signal data set based on a pulse sound source and a microphone array specifically includes: Arrange microphone arrays and pulse sound sources in the tunnel; When there is no train in the tunnel, the pulse sound source is played. After a stable sound field is formed, the pulse sound source is turned off. At this time, the microphone array is used to collect data and record the data for a period of time when it decays to the background noise level, so as to obtain the original signal data of each measuring point of the microphone array when there is no train. When the train stops at different positions in the tunnel, the pulse sound source is played respectively. After a stable sound field is formed, the pulse sound source is turned off, and data is collected using the microphone array. The data for the period of time when it decays to the background noise level is recorded, thereby obtaining the original signal data of each measuring point of the microphone array when the train is located at different positions.

[0025] Specifically, the number of microphone arrays is greater than 2 and is evenly distributed in the tunnel; the microphone array includes a plurality of microphone sensors in the same plane, the plane is parallel to the tunnel cross section, and each microphone sensor serves as a measuring point; like Figure 2 The figure shows the whole arrangement structure of the microphones. In this embodiment, five microphone sensors are arranged, namely sensor 1, sensor 2, sensor 3, sensor 4 and sensor 5, corresponding to measuring points 1, 2, 3, 4 and 5 respectively; wherein, measuring points 1 to 3 are at a height of 1.2 m from the tunnel ground, the horizontal distances from measuring point 1 and measuring point 3 to measuring point 2 are both 1.2 m, and measuring points 2, 4 and 5 are on the central axis of the tunnel section, with heights of 1.2 m, 1.8 m and 2.4 m respectively.

[0026] The measuring points are kept at a distance of 1.2 m to avoid being too close and causing the number of irrelevant positions to be less than the actual number of measured positions; the measuring points are kept at a distance of 2 m from the pulse sound source to avoid excessive influence of direct sound from the sound source to the microphone; the distance between the measuring point and the nearest wall in the tunnel should be at least 1 / 4 wavelength, which is about 1 m in this embodiment.

[0027] Specifically, Figure 3As shown, the pulse sound source is placed at the center of the tunnel floor; in this embodiment, based on the center line of the first carriage of the train, the train is parked at five positions in the tunnel: position ①, position ②, position ③, position ④, position ⑤, and the five positions are evenly distributed in the tunnel; the right direction is the travel direction of the train, Figure 3 The diagram shown is a schematic diagram of the train at position ⑤; In this embodiment, step S2 processes the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, respectively, to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; here, taking the tunnel without a train as an example, the original signal data of each measuring point of the microphone array when there is no train is processed to obtain the tunnel sound absorption coefficient value when there is no train. The specific steps are as follows: Step S21: Based on the original signal data of a certain measuring point of the non-train microphone array, the sampling frequency is adjusted to perform resampling to obtain new signal data; Specifically, use MATLAB software to import the original signal data of a certain measuring point and draw the original signal image, such as Figure 4 As shown; after the sound source is cut off, the attenuation start time, end time and attenuation speed of each frequency band are different. It is necessary to adjust the sampling frequency according to the different attenuation time of each frequency band, resample the original data, and obtain new signal data, such as Figure 5 shown.

[0028] Step S22: performing filtering conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Specifically, step S22 includes: Design a filter to filter and plot the new signal data according to 1 / 3 octave. The filter is designed to perform bandpass filtering according to the 1 / 3 octave center frequency (including 100, 125, 160, 200... Hz). The designed filter is as follows Figure 6 As shown; The filtered signal data is subjected to coordinate transformation processing to convert the frequency domain signal into the time domain signal; Figure 7 As shown; Take the logarithm of the amplitude of the time domain signal to obtain the peak point set; Figure 8-Figure 9 As shown; Based on the peak point set, find the starting point of decay and use it to intercept the decay interval data, where Fig. 9 The middle blue part is the decay interval data; like Fig.10 As shown, a linear fit is performed on the decay interval data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point; Based on the attenuation slope of each 1 / 3 center frequency at a certain measuring point, calculate the reverberation time of each 1 / 3 center frequency at a certain measuring point.

[0029] Among them, the formula for calculating the reverberation time of each 1 / 3 center frequency of a certain measurement point is as follows:

[0030] in, k Indicates the attenuation slope of a certain 1 / 3 center frequency; T 60 Indicates the reverberation time corresponding to the decay slope.

[0031] Step S23: using the Sabine formula, according to the reverberation time of each 1 / 3 center frequency of a certain measuring point, obtain a one-third octave band spectrum of the sound absorption coefficient of a certain measuring point; Specifically include: Get tunnel volume and tunnel area; The Sabin formula is used to calculate the sound absorption coefficient of each 1 / 3 center frequency at a certain measuring point according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the tunnel volume and the tunnel area; the Sabin formula is expressed as follows:

[0032] in, V represents the volume of the tunnel; s represents the area of ​​the tunnel; Indicates the sound absorption coefficient of a certain 1 / 3 center frequency; The sound absorption coefficients of each 1 / 3 center frequency of a certain measuring point are combined to obtain a one-third octave band spectrum of the sound absorption coefficient of a certain measuring point.

[0033] Step S24: obtaining the tunnel sound absorption coefficient value when there is no train based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point; Specifically include: Based on the one-third octave band spectrum of the sound absorption coefficient of a certain measuring point, calculate the average value of the sound absorption coefficient of all 1 / 3 center frequencies of a certain measuring point to obtain the average sound absorption coefficient of a certain measuring point; The average sound absorption coefficient of all measuring points is obtained according to the above method, and then the average sound absorption coefficient of all measuring points is calculated by taking the average value to obtain the tunnel sound absorption coefficient value when there is no train.

[0034] In this embodiment, based on the above steps, we can obtain the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions; the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions are fitted by using a function fitting method to obtain a tunnel sound absorption coefficient change curve when simulating a train passing, such as Fig.11 shown.

[0035] Example 2

[0036] The embodiment of the present invention introduces a tunnel sound absorption coefficient testing system simulating a train passing through, comprising: A data acquisition module, used for acquiring an acoustic signal data set based on a pulse sound source and a microphone array, wherein the acoustic signal data set includes original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions; A data processing module is used to process the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, so as to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; The processing process includes: Based on the original signal data of a certain measuring point of the microphone array when there is no train or the train is at a different position, the sampling frequency is adjusted to perform resampling to obtain new signal data; Perform filtering and conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Using Sabine's formula, according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is obtained; Based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, the tunnel sound absorption coefficient value when there is no train or the train is located at different positions is obtained; The data fitting module is used to fit the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions by using a function fitting method, so as to obtain a tunnel sound absorption coefficient variation curve when simulating the train passing through.

[0037] Example 3

[0038] In this embodiment, the present invention further introduces a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in Embodiment 1 are implemented.

[0039] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0040] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0041] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0042] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0043] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A method for testing the sound absorption coefficient of a tunnel when simulating a train passing through, characterized in that: include: S1: Acquire an acoustic signal data set based on a pulse sound source and a microphone array, wherein the acoustic signal data set includes original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions; S2: Processing the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, respectively, to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; The processing process includes: Based on the original signal data of a certain measuring point of the microphone array when there is no train or the train is at a different position, the sampling frequency is adjusted to perform resampling to obtain new signal data; Perform filtering and conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Using Sabine's formula, according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is obtained; Based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, the tunnel sound absorption coefficient value when there is no train or the train is located at different positions is obtained; S3: Use function fitting to fit the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions, and obtain the tunnel sound absorption coefficient change curve when simulating the train passing.

2. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 1, characterized in that: The method of acquiring an acoustic signal data set based on a pulse sound source and a microphone array comprises: Arranging a microphone array and a pulse sound source in the tunnel; wherein the microphone array includes a plurality of microphone sensors in the same plane, the plane is parallel to the tunnel cross section, and each microphone sensor serves as a measuring point; When there is no train in the tunnel, the pulse sound source is played. After a stable sound field is formed, the pulse sound source is turned off. At this time, the microphone array is used to collect data and record the data for a period of time when it decays to the background noise level, so as to obtain the original signal data of each measuring point of the microphone array when there is no train. When the train stops at different positions in the tunnel, the pulse sound source is played respectively. After a stable sound field is formed, the pulse sound source is turned off, and data is collected using the microphone array. The data for the period of time when it decays to the background noise level is recorded, thereby obtaining the original signal data of each measuring point of the microphone array when the train is located at different positions.

3. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 2, characterized in that: The number of the microphone arrays is greater than 2 and is evenly distributed in the tunnel.

4. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 3 is characterized in that: The pulse sound source is placed at the center of the tunnel floor.

5. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 1, characterized in that: The filtering and conversion processing is performed on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point, including: Filter the new signal data according to 1 / 3 octave to obtain filtered signal data; The filtered signal data is subjected to coordinate transformation processing to obtain a time domain signal; Take the logarithm of the amplitude of the time domain signal to obtain the peak point set; Based on the peak point set, find the starting point of decay and use it to intercept the decay interval data; Perform linear fitting on the decay interval data to obtain the attenuation slope of each 1 / 3 center frequency at a certain measurement point; Based on the attenuation slope of each 1 / 3 center frequency at a certain measuring point, calculate the reverberation time of each 1 / 3 center frequency at a certain measuring point.

6. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 5, characterized in that: The formula for calculating the reverberation time of each 1 / 3 center frequency at a certain measurement point is as follows: ； Where k represents the attenuation slope of a certain 1 / 3 center frequency; T 60 Indicates the reverberation time corresponding to the decay slope.

7. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 6, characterized in that: The Sabin formula is used to obtain the one-third octave frequency spectrum of the sound absorption coefficient of a certain measuring point according to the reverberation time of each 1 / 3 center frequency of a certain measuring point, including: Get tunnel volume and tunnel area; The Sabin formula is used to calculate the sound absorption coefficient of each 1 / 3 center frequency at a certain measuring point according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the tunnel volume and the tunnel area; the Sabin formula is expressed as follows: ； Where V represents the tunnel volume; s represents the tunnel area; Indicates the sound absorption coefficient of a certain 1 / 3 center frequency; The sound absorption coefficients of each 1 / 3 center frequency of a certain measuring point are combined to obtain a one-third octave band spectrum of the sound absorption coefficient of a certain measuring point.

8. The method for testing the tunnel sound absorption coefficient when simulating a train passing through according to claim 7, characterized in that: The tunnel sound absorption coefficient values ​​when there is no train or when the train is located at different positions are obtained based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, including: Based on the one-third octave band spectrum of the sound absorption coefficient of a certain measuring point, calculate the average value of the sound absorption coefficient of all 1 / 3 center frequencies of a certain measuring point to obtain the average sound absorption coefficient of a certain measuring point; The average sound absorption coefficient of all measuring points is obtained according to the above method, and then the average sound absorption coefficient of all measuring points is averaged to obtain the tunnel sound absorption coefficient value when there is no train or the train is located at different positions.

9. A tunnel sound absorption coefficient testing system simulating train passing, characterized in that: include: A data acquisition module, used for acquiring an acoustic signal data set based on a pulse sound source and a microphone array, wherein the acoustic signal data set includes original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions; A data processing module is used to process the original signal data of each measuring point of the microphone array when there is no train and when the train is at different positions, so as to obtain the tunnel sound absorption coefficient value when there is no train and when the train is at different positions; The processing process includes: Based on the original signal data of a certain measuring point of the microphone array when there is no train or the train is at a different position, the sampling frequency is adjusted to perform resampling to obtain new signal data; Perform filtering and conversion processing on the new signal data to obtain the attenuation slope of each 1 / 3 center frequency of a certain measuring point, thereby calculating the reverberation time of each 1 / 3 center frequency of a certain measuring point; Using Sabine's formula, according to the reverberation time of each 1 / 3 center frequency at a certain measuring point, the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point is obtained; Based on the one-third octave band spectrum of the sound absorption coefficient at a certain measuring point, the tunnel sound absorption coefficient value when there is no train or the train is located at different positions is obtained; The data fitting module is used to fit the tunnel sound absorption coefficient values ​​when there is no train and when the train is at different positions by using a function fitting method, so as to obtain a tunnel sound absorption coefficient variation curve when simulating the train passing through.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for testing the sound absorption coefficient of a tunnel when simulating a train passing through as described in any one of claims 1 to 8 are implemented.

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