Rail transit wall-attached noise elimination layer structure and design method

Abstract

The invention discloses a rail transit wall-attached noise elimination layer structure and a design method, the noise elimination layer structure is composed of three layers of rollable sound absorption materials, the three layers of rollable sound absorption materials are a noise capture layer, an acoustic corridor layer and a low-frequency suppression layer in the radial direction of a tunnel, and a plurality of regular hexagon micropore channel units are arranged on the noise capture layer in an array mode; the acoustic corridor layer is provided with staggered cavity corridor structures in an array manner, so that sound waves are reflected for multiple times to convert sound energy into internal energy; the low-frequency suppression layer is provided with the arrayed mass concentration units, and the vibration of a system formed by the arrayed mass concentration units and the thin film is opposite through the density difference between the arrayed mass concentration units and the thin film, so that the sound absorption performance of the whole material is improved. The structure of the silencing layer can be optimized in a targeted mode according to the psychoacoustic annoyance degree, the design of the structure of the silencing layer meets the comfort degree of a driver and passengers in the train running process, work errors caused by insensitive auditory sense of train workers are prevented, and safe running of the train is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of rail transit noise control, and is a structure and design method of a rail transit wall-attached sound-absorbing layer. Background Art

[0002] With the rapid development of underground transportation projects such as urban rail transit, subways, and high-speed railways, vehicle-induced reverberation noise in tunnels has become a key factor affecting tunnel operator comfort and the quality of the surrounding environment. This noise primarily originates from the interaction between trains, the tracks, and the tunnel structure during travel. In tunnels, due to the reflection, refraction, and diffraction of sound waves, the noise continuously reverberates and resonates between the train compartment and the tunnel walls, severely impacting the passenger experience and potentially adversely affecting the tunnel's machinery and surrounding environment.

[0003] Vehicle-induced noise in tunnels is typically predominantly low- and medium-frequency. This type of noise is highly penetrating, especially at high speeds. The noise inside the vehicle cabin can be loud and uncomfortable, impacting passengers' travel experience and health. Vehicle-induced noise and vibration can also affect the stability of ventilation systems, communications facilities, and other equipment within the tunnel, reducing their lifespan and operating efficiency. Residential and commercial areas outside the tunnel may also be affected by the transmission of noise from within the tunnel, causing noise pollution and impacting the quality of life of surrounding residents.

[0004] Currently, effective measures to address vehicle-induced reverberation noise in tunnels are not widely available. In particular, there is a lack of innovative devices that can absorb noise at specific dominant frequencies, which are more easily perceived by the human ear, within a specific section and can adapt to the diverse morphologies of tunnel walls. Existing sound-absorbing material technologies, elastic rails, or floating rails are inefficient at reducing vibration and noise, and lack specificity for noise at specific dominant frequencies, which are more easily perceived by the human ear. This makes it difficult to meet the growing demand for tunnel noise control. Summary of the Invention

[0005] The present invention aims to develop a novel device and design method to fill the current lack of such practical applications. Specifically, it aims to eliminate vehicle-induced reverberation noise of a specific dominant frequency within a specific section of a shield tunnel. This rail transit anechoic layer effectively suppresses low- and mid-frequency noise within tunnels, while also achieving optimal sound absorption efficiency.

[0006] In order to achieve the above technical objectives of the present invention, the present invention is implemented through the following technical solutions:

[0007] A rail transit wall-mounted sound-absorbing layer structure includes three layers of rollable sound-absorbing material, which are sequentially arranged along the tunnel radial direction toward the tunnel wall: a noise capture layer, an acoustic corridor layer, and a low-frequency suppression layer, wherein:

[0008] A plurality of regular hexagonal microporous channel units are arranged in an array on the noise capture layer;

[0009] The acoustic corridor layer is provided with staggered cavity corridor units, the number of which is the same as that of the regular hexagonal microporous channel units and which are coaxially connected in series with the regular hexagonal microporous channel units. The staggered cavity corridor units are provided with cavities capable of multiple reflections of noise to convert sound energy into internal energy.

[0010] The low-frequency suppression layer is an elastic film provided with arrayed mass concentrated units. Due to the difference in density between the arrayed mass concentrated units and the elastic film, the system consisting of the arrayed mass concentrated units and the elastic film vibrates in an anti-phase manner, thereby improving the sound absorption performance of the entire sound absorbing material layer.

[0011] The geometric data of the sound-absorbing layer structure is obtained by the following formula:

[0012]

[0013] in,

[0014] h is the total thickness of the noise capture layer and the acoustic corridor layer, b is the distance between the center points of the arrayed regular hexagonal microporous channel units, r is the circumscribed circle radius of the regular hexagonal microporous channel unit, p is the opening ratio after fitting the optimal sound absorption efficiency data of the noise capture layer, and PA' is the improved Zwicker psychoacoustic annoyance index.

[0015] Beneficial effects: The present invention can optimize the structure of the sound-absorbing layer in a targeted manner according to the psychoacoustic annoyance level, so that the design of the sound-absorbing layer structure meets the comfort level of drivers and passengers during train travel, prevents train staff from making work errors due to poor hearing, ensures the safe operation of the train, and protects the physical and mental health of passengers.

[0016] As a further preferred embodiment, the geometric shape of a single mass concentration unit in the arrayed mass concentration unit is a cone, the radius of the base and the height of the cone are respectively the same as the circumscribed circle radius of the regular hexagonal microporous channel unit, and the bottom of the cone is fixed on the elastic film in the same array form as the arrayed regular hexagonal microporous channel unit; the edge of the elastic film is fixed on the tensioning support frame structure and is tensioned.

[0017] As a further preferred embodiment, each of the staggered cavity corridor units includes a central channel, which is coaxially connected in series with the regular hexagonal microporous channel unit, and a plurality of staggered cavity corridor units connected to the central channel are staggered along the axial direction of the central channel to form a staggered cavity corridor structure.

[0018] Beneficial effect: Sound waves can be reflected multiple times and dissipated in the staggered cavity corridor structure.

[0019] As a further preferred embodiment, the arrayed mass concentration unit has a density of 6000-11000 kg / m 3 The material is stable in the air temperature range of -40℃-45℃.

[0020] Beneficial effect: Through the difference in density between the arrayed mass concentrated units and the film, the system composed of the arrayed mass concentrated units and the film vibrates in anti-phase, thereby improving the sound absorption performance of the entire material.

[0021] As a further preferred embodiment, the material of the tension support frame structure is aluminum, the shape of the tension support frame structure is square, the number of sound-absorbing coupling structure units supported within the range of a single square frame structure is 1-200, and the inner margin is 0.5-8 mm.

[0022] Beneficial effects: supporting the arrayed mass concentrated units and the tensioned membrane, so that the arrayed mass concentrated units and the membrane can vibrate at a certain frequency, thereby making the system composed of the arrayed mass concentrated units and the membrane vibrate in an anti-phase manner, thereby improving the sound absorption performance of the entire material and being able to adapt to the diversity of tunnel wall morphology.

[0023] The present invention further discloses a design method for the rail transit wall-mounted sound-absorbing layer structure, comprising the following steps:

[0024] S1. Acquire noise data in the passenger compartment of a train at speeds of 60 km / h, 70 km / h, and 80 km / h to obtain the noise frequency and sound pressure level in the passenger compartment, thereby obtaining the main frequency of the noise and the corresponding A-weighted sound pressure level;

[0025] S2. using the collected binaural noise signals in the passenger compartment to obtain an annoyance degree through a psychoacoustic annoyance degree calculation method;

[0026] S3. Substituting the obtained annoyance data into the fitting formula based on the optimal sound absorption efficiency data of the noise capture layer to determine the main geometric dimensions of the noise capture layer and the acoustic corridor layer;

[0027] The optimal sound absorption efficiency data fitting formula of the noise capture layer is:

[0028] θ=5+40sin(0.001f), p=0.09tan(0.0005f)+0.001L Aeq ,in,

[0029] θ is the opening angle, p is the opening ratio, f is the main frequency of the noise, L Aeq It is the A-weighted sound pressure level corresponding to the main frequency of the noise.

[0030] Beneficial effect: The design method of the present invention obtains the noise frequency and sound pressure level inside the train and determines the main geometric design parameters of the device based on the annoyance of the noise, so as to absorb the main frequency of the noise in a targeted manner.

[0031] As a further preferred embodiment, the main frequency f of the noise is taken as the frequency at which the A sound level in the noise data collection result reaches the maximum value.

[0032] Beneficial effect: The main frequency f of the noise is taken as the frequency at which the A sound level in the noise data collection result reaches the maximum value, which can specifically improve the absorption efficiency of the noise frequency band that is more easily perceived by the human ear.

[0033] As a further preferred embodiment, in step S2, the psychoacoustic annoyance calculation method is to use the binaural signal of the cabin noise obtained by the artificial head data acquisition system, and use ArtemiS10.00 software to calculate the A-weighted sound pressure level L of each sound sample. Aeq , loudness N and wow / flutter F data, and then use the improved Zwicker psychoacoustic annoyance calculation formula to get the noise-based annoyance degree;

[0034] The improved Zwicker psychoacoustic annoyance calculation formula is as follows:

[0035]

[0036] In the above formula, PA' is the improved Zwicker psychoacoustic annoyance, N5 is the cumulative percentage loudness, S is sharpness, F is shake, R is roughness, T is pitch, w is the pitch, s is the weight coefficient related to sharpness, w FR is the weight coefficient related to slope F and roughness R, w T is the weight coefficient related to the tone scheduling.

[0037] Beneficial effect: The formula uses three correction factors w s , w FR , w T The basic loudness N5 is weighted and modified to more accurately reflect the human psychological response to complex sounds. The model combines multiple psychoacoustic parameters to be closer to the subjective auditory perception of the human ear. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the noise elimination layer structure and its noise elimination coupling structural unit and principle of the present invention;

[0039] Figure 2 Schematic diagram of the structure of the noise capture layer of the present invention;

[0040] Figure 3 This is a schematic structural diagram of the staggered cavity corridor unit of the present invention;

[0041] Figure 4 It is the axial cross-section of the staggered cavity corridor unit;

[0042] Figure 5 Schematic diagram of the structure of the low-frequency suppression layer of the present invention;

[0043] Figure 6 This is a schematic diagram of the principle of the noise elimination coupling structure of the present invention;

[0044] Figure 7 Schematic diagram of the arrangement of noise measurement points in a vehicle according to a specific embodiment of the present invention;

[0045] Figure 8 2. It is a schematic diagram of a vehicle interior noise test site according to a specific embodiment of the present invention;

[0046] Figure 9 is a fitted image of the optimal sound absorption efficiency of the noise capture layer geometric design of the present invention;

[0047] Among them, 1. Sound-absorbing layer structure; 2. Noise capture layer; 3. Acoustic corridor layer; 4. Low-frequency suppression layer; 5. Sound-absorbing coupling structure unit; 6. Regular hexagonal microporous channel unit; 7. Staggered cavity corridor unit; 7-1. Central channel; 7-2. Cavity; 8. Arrayed mass concentration unit; 9. Elastic film; 10. Tensile support frame structure. DETAILED DESCRIPTION

[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1:

[0050] This embodiment is a rail transit wall-mounted sound-absorbing layer structure. Figure 1 The anechoic layer structure includes three layers of acoustic structures, namely a noise capture layer, an acoustic corridor layer, and a low-frequency suppression layer. The anechoic layer structure is manufactured according to the target structural parameters determined by the following anechoic layer structure design method.

[0051] The vehicle in a specific section of a domestic line was selected to study the noise characteristics of the vehicle train in a tunnel environment, and the measurement points were arranged in the middle of the train compartment. Figure 6 As shown, the in-car measurement point is 1.2m above the floor. The in-car noise test site conditions are as follows: Figure 7As shown in the figure, the noise signal was collected using the Danish B&KLANXI data acquisition and analysis system and tested using a 50-channel spherical acoustic array. The 1 / 3 octave spectrum of the train interior noise at the train operating speed in the section was obtained. The main frequency of the noise was obtained to be 850 Hz, and the corresponding A-weighted sound pressure level was 72.3 dB. The data was substituted into the fitting formula for the optimal sound absorption efficiency of the noise capture layer.

[0052] Among them, the data fitting formula for the optimal sound absorption efficiency of the noise capture layer is: the noise capture layer has the characteristics of enhancing low-frequency sound absorption and weakening high-frequency sound absorption compared to the non-perforated plate. The noise capture layer with different opening angles and opening ratios within the thickness design range of 5mm-20mm is numerically calculated to obtain the best opening angle and opening ratio for the noise capture layer under different main noise frequencies. Figure 8 As shown, the data is fitted to obtain the optimal sound absorption efficiency data fitting formula of the noise capture layer:

[0053] θ=5+40sin(0.001f), p=0.09tan(0.0005f)+0.001L Aeq1

[0054] In the above formula: θ is the opening angle, p is the opening ratio, f is the main frequency of the noise, L Aeq It is the A-weighted sound pressure level corresponding to the main frequency of the noise.

[0055] At the same time, an artificial head data acquisition system is used to collect binaural signal sound samples at the measuring point in the middle of the train compartment, and the A-weighted sound pressure level L of the sound samples is calculated using ArtemiS10.00 software. Aeq2 , loudness N, jitter F, roughness R, sharpness S, pitch T, etc., and then the noise-based annoyance degree is obtained through the improved Zwicker psychoacoustic annoyance degree calculation formula.

[0056] The binaural signals obtained by the artificial head data acquisition system are usually used to calculate the noise evaluation value using the following formula:

[0057]

[0058] In the above formula: L s is the sound level of the sound sample, L L is the left ear sound level, L R is the sound level in the right ear.

[0059] Among them, the improved Zwicker psychoacoustic annoyance calculation formula includes the following formula:

[0060]

[0061] In the above formula: PA' is the improved Zwicker psychoacoustic annoyance index, N5 is the cumulative percentage loudness, S is sharpness, F is wow and flutter, R is roughness, and T is pitch.

[0062] Combining the above data, the geometric data design values ​​of the sound-absorbing layer structure can be obtained: opening angle θ = 35°, opening ratio p = 11%, total thickness of the noise capture layer and acoustic corridor layer Opening spacing The radius of the circumscribed circle of a hexagonal opening arranged in a square

[0063] The inner diameter of the shield tunnel is 5500mm. The axial length of the sound-absorbing layer structure laid on both sides of the inner wall of the shield tunnel is 38500mm, and the circumferential length laid upward along the bottom of the roadbed on one side is 4600mm.

[0064] Among them, the sound-absorbing layer structure 1 is composed of a noise capture layer 2, an acoustic corridor layer 3, and a low-frequency suppression layer 4 radially inwardly of the tunnel wall; the noise capture layer 2 is provided with an arrayed regular hexagonal microporous channel unit 6 for transmitting noise to the acoustic corridor layer 3 and the low-frequency suppression layer 4; the acoustic corridor layer 3 is provided with staggered cavity corridor units 7 for absorbing noise; the low-frequency suppression layer 4 is provided with an arrayed mass concentration unit 8, an elastic film 10 and a tension support frame structure 11.

[0065] The arrayed regular hexagonal microporous channel units 6 , the staggered cavity corridor units 7 and the arrayed mass concentration units 8 on the sound-absorbing layer structure are combined to form a sound-absorbing coupling structure unit 5 .

[0066] Among them, the noise capture layer 2 is composed of a melamine foam porous sound-absorbing material sheet through openings, and the opening method is an arrayed regular hexagonal microporous channel unit 6, the opening rate is about 11%, and the thickness of the porous sound-absorbing material sheet is 5 mm; the arrayed regular hexagonal microporous channel unit 6 is a regular hexagonal opening shape, the radius of the regular hexagonal circumscribed circle on the tunnel wall side is 2.5 mm, and the opening angle is 35°.

[0067] Among them, the acoustic corridor layer 3 is composed of a melamine foam porous sound-absorbing material sheet through openings, the opening method is a staggered cavity corridor unit 7, the opening rate is about 11%, and the thickness of the porous sound-absorbing material sheet is 5 mm; each of the staggered cavity corridor units 7 includes a central channel 7-1, the central channel 7-1 is coaxially connected in series with the regular hexagonal microporous channel unit, and a plurality of cavities 7-2 connected to the central channel 7-1 are staggered along the axial direction of the central channel 7-1 to form a staggered cavity corridor structure.

[0068] The low-frequency suppression layer 4 is composed of an arrayed mass concentration unit 8, an elastic film 10, and a tension support frame structure 11. The arrayed mass concentration unit 8 is a stainless steel cone with its bottom surface glued to the film. The radius of the bottom circle is 2.5mm and the height of the cone is 2.5mm. The elastic film 10 is a 0.2mm polyethylene film. The tension support frame structure 11 is a 2800kg / m 3 The square aluminum frame has a structure with a number of 100 noise-cancelling coupling structural units 5 supported within the single square aluminum frame structure, and an inner margin of 4 mm.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rail transit wall-mounted sound-absorbing layer structure, comprising three layers of rollable sound-absorbing material, which are sequentially arranged along the tunnel radial direction toward the tunnel wall: a noise capture layer (2), an acoustic corridor layer (3), and a low-frequency suppression layer (4), wherein: A plurality of regular hexagonal microporous channel units (6) are arranged in an array on the noise capture layer (2); The acoustic corridor layer (3) is provided with staggered cavity corridor units (7) whose number is the same as the regular hexagonal microporous channel units (6) and which are coaxially connected in series with the regular hexagonal microporous channel units (6). The staggered cavity corridor units (7) have cavities capable of multiple reflections of noise to convert sound energy into internal energy. The low-frequency suppression layer (4) is an elastic film provided with arrayed mass concentration units. Due to the difference in density between the arrayed mass concentration units and the elastic film, the system composed of the arrayed mass concentration units and the elastic film vibrates in an anti-phase manner, thereby improving the sound absorption performance of the entire sound absorption material layer. The geometric data of the sound-absorbing layer structure is obtained by the following formula: in, h is the total thickness of the noise capture layer and the acoustic corridor layer, b is the distance between the center points of the arrayed regular hexagonal microporous channel units, r is the circumscribed circle radius of the regular hexagonal microporous channel unit, p is the opening ratio after fitting the optimal sound absorption efficiency data of the noise capture layer, and PA' is the improved Zwicker psychoacoustic annoyance index.

2. The rail transit wall-mounted sound-absorbing layer structure according to claim 1, characterized in that: The geometric shape of a single mass concentration unit in the arrayed mass concentration unit (8) is a cone, the base radius and height of the cone are respectively the same as the circumscribed circle radius of the regular hexagonal microporous channel unit (6), and the base of the cone is fixed on the elastic film (10) in the same array form as the arrayed regular hexagonal microporous channel unit (6); the edge of the elastic film (10) is fixed on the tension support frame structure (11) and is tensioned.

3. The rail transit wall-mounted sound-absorbing layer structure according to claim 1, characterized in that: Each of the staggered cavity corridor units (7) includes a central channel, the central channel is coaxially connected in series with the regular hexagonal microporous channel unit (6), and a plurality of staggered cavity corridor units connected to the central channel are staggered along the axial direction of the central channel to form a staggered cavity corridor structure.

4. The rail transit wall-mounted sound-absorbing layer structure according to claim 1, characterized in that: The arrayed mass concentration unit (8) has a density of 6000-11000 kg / m 3 The material is stable in the air temperature range of -40℃-45℃.

5. The rail transit wall-mounted sound-absorbing layer structure according to claim 1, characterized in that: The material of the tension support frame structure (11) is aluminum, the shape of the tension support frame structure (11) is square, the number of the sound-absorbing coupling structural units (5) supported within the range of a single square frame structure is 1-200, and the inner margin is 0.5-8 mm.

6. A design method for a rail transit wall-mounted sound-absorbing layer structure as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Acquire noise data in the passenger compartment of a train at speeds of 60 km / h, 70 km / h, and 80 km / h to obtain the noise frequency and sound pressure level in the passenger compartment, thereby obtaining the main frequency of the noise and the corresponding A-weighted sound pressure level; S2. using the collected binaural noise signals in the passenger compartment to obtain an annoyance degree through a psychoacoustic annoyance degree calculation method; S3, substituting the obtained annoyance data into the main geometric dimensions of the noise capture layer (2) and the acoustic corridor layer (3) determined according to the fitting formula of the optimal sound absorption efficiency data of the noise capture layer; The optimal sound absorption efficiency data fitting formula of the noise capture layer is: θ=5+40sin(0.001f), p=0.09tan(0.0005f)+0.001L Aeq ,in, θ is the opening angle, p is the opening ratio, f is the main frequency of the noise, L Aeq It is the A-weighted sound pressure level corresponding to the main frequency of the noise.

7. The design method according to claim 6, characterized in that: The main frequency f of the noise is the frequency at which the A sound level reaches the maximum value in the noise data collection result.

8. The design method according to claim 6, characterized in that: In step S2, the psychoacoustic annoyance calculation method is to use the binaural signal of the cabin noise obtained by the artificial head data acquisition system, and use ArtemiS10.00 software to calculate the A-weighted sound pressure level L of each sound sample. Aeq , loudness N and wow / flutter F data, and then use the improved Zwicker psychoacoustic annoyance calculation formula to get the noise-based annoyance degree; The calculation formula of the improved Zwicker psychoacoustic annoyance degree is as follows: In the above formula: N5 is the cumulative percentage loudness, S is the sharpness, F is the shake, R is the roughness, T is the pitch, w is the pitch s is the weight coefficient related to sharpness, w FR is the weight coefficient related to the flutter F and roughness R, w T is the weight coefficient related to the tone scheduling.

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