CN109148123B - Acoustic metamaterial barrier system for transformer noise spatial distribution characteristics - Google Patents

Abstract

An adjustable acoustic metamaterial barrier system aiming at the spatial distribution characteristics of transformer noise is composed of an acoustic metamaterial barrier (3) and a noise measurement and analysis system (2). The acoustic metamaterial barrier (3) is composed of a metamaterial support bracket (7) and a fractal structure acoustic metamaterial module (8). The metamaterial support bracket (7) is parallel to the sound source surface (1) of the transformer. The fractal structure acoustic metamaterial module (8) is embedded in the metamaterial support bracket (4). The noise measurement and analysis system (2) measures the noise within the range of the acoustic metamaterial barrier (3), and analyzes the noise spatial distribution characteristics. According to the spatial distribution characteristics of noise, a fractal structure acoustic metamaterial module (8) with different parameters is selected. When the sound wave is transmitted to the acoustic metamaterial barrier (3), since the parameters of the acoustic metamaterial module (8) are selected according to the noise distribution characteristics of the corresponding position, the noise amplitude of the target noise reduction area can be greatly reduced.

Description

Acoustic metamaterial barrier system based on spatial distribution characteristics of transformer noise

technical field

The present invention relates to an acoustic metamaterial barrier.

Background technique

The noise of the transformer body mainly comes from the vibration of the iron core and the winding, and the noise is concentrated in the frequency multiplication of 100Hz, mainly low-frequency noise. Transformer fan noise is broadband noise between 500-2000Hz. With the construction of the city, a large number of 110kV and 220kV substations are getting closer and closer to the central city. The noise propagation environment is complex, and the interference and diffraction of sound waves lead to increasingly prominent transformer noise problems, which inevitably affect the station staff and nearby residents. Therefore, how to control the transformer noise in the transmission route has become an important problem to be solved urgently by the environmental protection department and the electric power department.

At present, the noise reduction methods for transformer noise mainly include active noise reduction and material noise reduction. Active noise reduction means active noise reduction. For example, Chinese patent CN106251855A "A Decentralized Virtual Sound Barrier for Transformer Noise Reduction" discloses that the active sound barrier is installed near the opening surface of the room, controlled by the sound source and error microphone. , reference sensor, multiple single-channel active controllers and peripheral circuits, which can control the noise radiated from the sound source in the room through the opening. The advantage of active sound barriers is flexible control, but the disadvantage is that when the number of arrays increases, the control is very difficult.

The noise of the transformer itself is mainly low-frequency noise, and the sound barrier made of traditional sound insulation materials has poor noise reduction effect on low-frequency noise. Acoustic metamaterials have extraordinary physical properties such as negative refraction, strong reflection, negative mass density, and negative bulk modulus. Compared with traditional materials, they have the advantages of large sound insulation and small thickness, and can achieve smaller-sized materials to control low-frequency noise and effectively compensate for The traditional material barrier is difficult to block low-frequency noise, and it has a good development prospect in the field of transformer noise reduction. Chinese patent CN106192785A "A full-band noise reduction barrier and shielding device for substations", the sound barrier includes a metamaterial low-frequency noise reduction layer and a high-frequency noise reduction layer, which are placed near the transformer and reduce the noise transmission path of the transformer. full-band noise. The acoustic metamaterial barrier disclosed in the patent does not consider the difference in the spatial distribution of noise. Once the sound barrier is established, it cannot be flexibly adjusted according to the distribution of the spatial sound field, resulting in poor noise reduction effect.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the prior art and propose an acoustic metamaterial barrier system aiming at the spatial distribution characteristics of transformer noise.

The acoustic metamaterial barrier system of the present invention includes an acoustic metamaterial barrier and a noise measurement and analysis system, which are placed outside the ventilation opening of the indoor transformer or around the outdoor transformer.

The acoustic metamaterial barrier is composed of a metamaterial support bracket and a fractal structure acoustic metamaterial module, and the fractal structure acoustic metamaterial module is embedded in the metamaterial support bracket.

When building an acoustic metamaterial barrier, the noise measurement and analysis system measures the noise characteristics at the location of the acoustic metamaterial barrier, and selects the fractal order and acoustic waveguide width parameters of each fractal structure acoustic metamaterial module of the acoustic metamaterial barrier according to the spatial distribution of the noise. When the sound source changes, the spatial sound field changes, and the noise is measured again through the noise measurement and analysis system. According to the changed sound field distribution, the fractal order and acoustic waveguide width of each fractal structure acoustic metamaterial module of the acoustic metamaterial barrier are adjusted. parameters, replace the previous fractal structure acoustic metamaterial module with the fractal structure acoustic metamaterial module of the acoustic metamaterial barrier after adjusting the parameters.

The metamaterial support bracket is a rectangular parallelepiped. Except for the top and bottom surfaces, the transformer has four-directional outer contour surfaces. Define the outer contour surface in any direction as the sound source surface of the transformer. The sound source surface of the transformer is parallel to the metamaterial support bracket, and there is a certain distance between them. The side of the metamaterial support bracket facing the sound source side of the transformer is provided with m×n rectangular through holes, where m and n are positive integers. The rectangular vias have the same size and are equally spaced to form an array.

The fractal structure acoustic metamaterial module is embedded in a rectangular through hole of the metamaterial support bracket, and the fractal structure acoustic metamaterial module in each rectangular through hole can be disassembled. The fractal structure acoustic metamaterial module is parallel to the sound source surface of the transformer, the surface close to the sound source surface of the transformer is the sound wave inlet surface, and the surface far from the sound source surface of the transformer is the sound wave exit surface. The plane perpendicular to the acoustic wave inlet surface and the acoustic wave exit surface is the cross section of the fractal structure acoustic metamaterial module.

The fractal structure acoustic metamaterial module is an array composed of fractal structure acoustic metamaterial units. The cross section of the acoustic metamaterial unit is a rectangular surface with a certain width of the Hilbert curve channel. A Hilbert curved channel of a certain width is called an acoustic waveguide.

The sound insulation frequency of the fractal structure acoustic metamaterial unit is closely related to the fractal order and the width of the acoustic waveguide.

Establish a fractal structure acoustic metamaterial element model, given the fractal order of the acoustic metamaterial element and the parameter range of the waveguide width, scan the waveguide width parameters under the given fractal order, and obtain the given order and waveguide through the sound field calculation. The amount of sound insulation of a wide acoustic metamaterial unit at different frequencies.

The sound pressure at the measurement point is calculated according to the coupling equation (1) of the structure field and the sound field and the sound pressure wave equation (2).

Among them, ρ ₀ is the mass density, v is the vibration velocity, p is the sound pressure, c is the sound velocity, and ▽ is the Hamiltonian.

Among them, ρ ₀ is the mass density, p is the sound pressure, c is the sound speed, ▽ is the Hamiltonian operator, and t is the sound wave propagation time.

The sound pressure level can be obtained from the sound pressure:

Among them, p is the sound pressure, _pre is the reference sound pressure, the international value is 2×10 ^-5 Pa, SPL is the sound pressure level, and the sound insulation is obtained according to the sound pressure level:

TL=SPL ₂ -SPL ₁ (4)

Among them, SPL ₂ is the sound pressure level at the measurement point when the metamaterial unit is added, SPL ₁ is the sound pressure level at the measurement point after adding the metamaterial unit, and TL is the sound insulation.

The frequency range with high sound insulation is the optimal sound insulation frequency range of the acoustic metamaterial unit with given parameters. According to the optimal sound insulation frequency range, the fractal order and acoustic waveguide width of a given fractal structure acoustic metamaterial unit corresponding to the sound insulation frequency range are selected.

Air circulates along acoustic waveguides in fractal-structured acoustic metamaterial cells.

The noise measurement and analysis system is composed of a sensor support bracket, a sound pressure sensor and a sound pressure signal processing module. The sound pressure sensor is placed on the sensor support bracket, and the sound pressure signal processing module is connected with the sound pressure sensor.

The sensor support bracket is parallel to the metamaterial support bracket, is arranged near the metamaterial support bracket, and is located on the same side of the transformer as the metamaterial support bracket. The sensor support bracket is a cuboid structure, the height is equal to the height of the metamaterial barrier support bracket, and the width is smaller than the width of the metamaterial barrier support bracket. The sensor support bracket includes a plurality of beams and vertical beams, the beams and the vertical beams intersect to form a plurality of rectangular through holes, the size of each rectangular through hole is the same, and the length of the rectangular through hole is less than or equal to the rectangular through hole of the metamaterial support bracket. 1/2 the length, and the width is less than or equal to 1/2 the width of the rectangular through hole of the metamaterial support bracket. The sensor support bracket can move in a direction parallel to the acoustic metamaterial barrier.

The sound pressure sensor is placed at the intersection of the transverse beam and the vertical beam of the sensor support bracket to form a sound pressure sensor array.

The sound pressure signal processing module includes a preamplifier, a filter, an A/D converter and a DSP processor. The input end of the preamplifier is connected to the sound pressure sensor to amplify the noise signal collected by the sound pressure sensor; the input end of the filter is connected to the output end of the preamplifier to filter out the noise signal collected by the sound pressure sensor The high-frequency components in the medium, the collected sound pressure analog signal is sent to the A/D converter from the output end of the filter; the signal is sampled by the A/D converter and then sent to the input end of the DSP processor; the DSP processor will The noise signal is subjected to interpolation calculation and spectrum analysis to obtain the noise distribution characteristics and spectrum characteristics within the range of the sensor support bracket.

The working process of the present invention is as follows: the sensor support bracket and the metamaterial support bracket have a small distance and are placed in parallel, and the sensor support bracket is aligned with the outer vertical beam of the metamaterial support bracket. The noise measurement and analysis system measures and records the noise. After the measurement is completed, keep the distance between the sensor support bracket and the metamaterial support bracket unchanged, and move the noise measurement and analysis system to measure the noise distribution in the next area until the measurement range covers the entire acoustic metamaterial barrier. The spatial distribution characteristics of noise within the acoustic metamaterial barrier are obtained by analysis. The noise measurement and analysis system performs spectrum analysis on the noise in the time domain to obtain the frequency domain characteristics of the noise, thereby obtaining the sound insulation frequency range of each rectangular through-hole position of the metamaterial support bracket. According to the principle that the optimal sound insulation frequency range is the same as the sound insulation frequency range of the rectangular through hole of the metamaterial support bracket, the acoustic metamaterial module with fractal structure is selected to be embedded in the rectangular through hole of the metamaterial support bracket. In the acoustic metamaterial unit of the fractal structure acoustic metamaterial module, the fractal order and the width of the acoustic wave guide are the fractal order and sound waves of the fractal structure acoustic metamaterial unit corresponding to the same sound insulation frequency range as the optimal sound insulation frequency range. Waveguide width. When the sound source changes, the spatial distribution of the noise changes, and the noise is measured again through the noise measurement and analysis system. According to the changed sound field distribution, the fractal structure acoustic metamaterial module at the position where the sound field changes is disassembled and replaced with one for the sound field. The fractal structure acoustic metamaterial module designed for the sound field characteristics after the change, the fractal structure acoustic metamaterial module designed for the sound field characteristics after the sound field change The fractal order of the fractal structure acoustic metamaterial unit and the width of the acoustic waveguide are the sound insulation frequencies after the sound field changes The range corresponds to the fractal order and acoustic waveguide width of the fractal-structured acoustic metamaterial unit.

When the sound wave is transmitted to the acoustic metamaterial barrier, since the parameters of the fractal structure acoustic metamaterial module are selected according to the noise distribution characteristics of the corresponding position, the amplitude of the sound wave in the target noise reduction area can be greatly reduced.

The invention establishes an adjustable acoustic metamaterial barrier according to the spatial distribution characteristics of transformer noise, which can effectively block transformer noise on the propagation path and reduce environmental noise pollution. Compared with the traditional sound barrier, when the barrier is established, the adjustable acoustic metamaterial barrier system of the present invention selects the parameters of the acoustic metamaterial module of the typed structure according to the measured sound field distribution, which can improve the noise reduction effect; at the same time, when the spatial distribution of noise changes , the acoustic metamaterial module can be adjusted according to the measured noise distribution to improve the flexibility of the sound barrier.

Description of drawings

1 is a schematic diagram of the tunable acoustic metamaterial barrier system of the present invention;

2 is a side view of the tunable acoustic metamaterial barrier system of the present invention;

3 is a front view of the noise measurement and analysis system of the present invention;

4 is a front view of the acoustic metamaterial barrier of the present invention;

5 is a structural diagram of a sound pressure signal processing module of the present invention;

Figure 6 is a cross-sectional view of the acoustic metamaterial unit of the present invention.

In the picture: 1 transformer sound source surface, 2 noise measurement and analysis system, 3 acoustic metamaterial barrier, 4 sensor support bracket, 5 sound pressure sensor, 6 sound pressure signal processing module, 7 metamaterial support bracket, 8 fractal structure acoustic metamaterial Modules, 9 preamplifiers, 10 filters, 11 A/D converters, 12 DSP processors, 13 first-order fractal structure acoustic metamaterial unit cross-sections, 14 second-order fractal structures acoustic metamaterial unit cross-sections, 15 third-order fractal structures Acoustic metamaterial unit cross section, 16 fourth order fractal structure acoustic metamaterial unit cross section.

Detailed ways

The present invention is further described below with reference to the accompanying drawings and specific embodiments.

As shown in FIGS. 1 and 2 , the adjustable acoustic metamaterial barrier system of the present invention for the spatial distribution characteristics of transformer noise is placed outside the indoor transformer vent or around the outdoor transformer, including an acoustic metamaterial barrier 3 and a noise measurement and analysis system 2 .

As shown in FIG. 4 , the acoustic metamaterial barrier 3 is composed of a metamaterial support bracket 7 and a fractal structure acoustic metamaterial module 8 , and the fractal structure acoustic metamaterial module 8 is embedded in the metamaterial support bracket 7 .

The metamaterial support bracket 7 is a rectangular parallelepiped. Except for the top and bottom surfaces, the transformer has four-directional outer contour surfaces. Define the outer contour surface in any direction as the sound source surface of the transformer. The transformer sound source surface 1 is parallel to the metamaterial support bracket 7 with a certain distance therebetween. The side of the metamaterial support bracket 7 facing the sound source surface 1 of the transformer is provided with m×n rectangular through holes, where m and n are positive integers. The rectangular vias have the same size and are equally spaced to form an array.

The fractal structure acoustic metamaterial module 8 is embedded in the rectangular through holes of the metamaterial support bracket 7, and the fractal structure acoustic metamaterial module 8 in each rectangular through hole can be disassembled and replaced. The fractal structure acoustic metamaterial module 8 is parallel to the sound source surface 1 of the transformer and the surface close to the sound source surface of the transformer is the sound wave inlet surface, and the surface far from the sound source surface 1 of the transformer is the sound wave exit surface. The plane perpendicular to the acoustic wave inlet surface and the acoustic wave exit surface is the cross section of the fractal structure acoustic metamaterial module 8 .

The fractal structure acoustic metamaterial module 8 is an array composed of fractal structure acoustic metamaterial units. The cross-section of the fractal-structured acoustic metamaterial unit is a rectangular surface with a Hilbert curve channel of a certain width, as shown in FIG. 6 . The cross-sectional form of the fractal structure acoustic metamaterial unit may be a first-order 13 , a second-order 14 , a third-order 15 or a fourth-order 16 . The order of the fractal structure acoustic metamaterial unit and the width of the acoustic waveguide are closely related to the sound insulation frequency.

Establish a fractal structure acoustic metamaterial element model, given the fractal order of the acoustic metamaterial element and the parameter range of the waveguide width, scan the waveguide width parameters under the given fractal order, and obtain the given order and waveguide through the sound field calculation. The amount of sound insulation of a wide acoustic metamaterial unit at different frequencies.

The sound pressure at the measurement point is calculated according to the coupling equation (1) of the structure field and the sound field and the sound pressure wave equation (2).

Among them, ρ ₀ is the mass density, v is the vibration velocity, p is the sound pressure, c is the sound velocity, and ▽ is the Hamiltonian.

Among them, ρ ₀ is the mass density, p is the sound pressure, c is the sound speed, ▽ is the Hamiltonian operator, and t is the sound wave propagation time.

The sound pressure level can be obtained from the sound pressure:

Among them, p is the sound pressure, _pre is the reference sound pressure, the international value is 2×10 ^-5 Pa, SPL is the sound pressure level, and the sound insulation is obtained according to the sound pressure level:

TL=SPL ₂ -SPL ₁ (4)

Among them, SPL ₂ is the sound pressure level at the measurement point when the metamaterial unit is added, SPL ₁ is the sound pressure level at the measurement point after adding the metamaterial unit, and TL is the sound insulation.

The frequency range with high sound insulation is the optimal sound insulation frequency range of the acoustic metamaterial unit with given parameters. According to the optimal sound insulation frequency range, the fractal order and acoustic waveguide width of the given fractal structure acoustic metamaterial unit corresponding to the same sound insulation frequency range are selected.

The noise measurement and analysis system 2 is composed of a sensor support bracket 4 , a sound pressure sensor 5 and a sound pressure signal processing module 6 . The sound pressure sensor 5 is placed on the sensor support bracket 4 , and the sound pressure signal processing module 6 is connected to the sound pressure sensor 5 . The front view of the sensor support bracket 4 and the sound pressure sensor 5 is shown in FIG. 3 .

The sensor support bracket 4 is parallel to the metamaterial support bracket 7 , is arranged near the metamaterial support bracket 7 , and is located on the same side of the transformer as the metamaterial support bracket 7 . The sensor support bracket 4 is a rectangular parallelepiped, its height is equal to that of the metamaterial support bracket 7 , and the width is smaller than the width of the metamaterial support bracket 7 . The sensor support bracket 4 includes a plurality of beams and vertical beams, the beams and the vertical beams intersect to form a plurality of rectangular through holes, the size of each rectangular through hole is the same, and the length of the rectangular through hole is less than or equal to the rectangular through hole of the metamaterial support bracket. 1/2 of the length of the hole, the width of the rectangular through hole is less than or equal to 1/2 of the width of the rectangular through hole of the metamaterial support bracket. The sensor support bracket 4 can move in a direction parallel to the metamaterial support bracket 7 .

The sound pressure sensor 5 is placed at the intersection of the horizontal beam and the vertical beam of the sensor support bracket 4 to form a sound pressure sensor array.

The sound pressure signal processing module 6 includes a preamplifier 9 , a filter 10 , an A/D converter 11 and a DSP processor 12 . The input end of the preamplifier 9 is connected to the sound pressure sensor 5 to amplify the noise signal collected by the sound pressure sensor 5; the input end of the filter 10 is connected to the output end of the preamplifier 9 to filter out the sound pressure The high-frequency components in the noise signal collected by the sensor 5, the collected sound pressure analog signal is sent to the A/D converter 11 from the output end of the filter 10; the signal is sent to the DSP processor 12 after sampling by A/D. At the input end, the DSP processor 12 performs spectrum analysis and interpolation calculation on the noise signal to obtain the noise distribution and spectrum characteristics within the range of the acoustic metamaterial barrier 3 .

The working process of the present invention is as follows: the sensor support bracket 4 and the metamaterial support bracket 7 are spaced at a small distance and placed in parallel, and the outer vertical beams of the two brackets are aligned. The noise measurement and analysis system 2 measures and records the noise. After the measurement is completed, keep the distance between the sensor support bracket 4 and the metamaterial support bracket 7 unchanged, and move the noise measurement and analysis system to measure the noise distribution in the next area until the measurement range covers the entire acoustic metamaterial. until barrier 3. The spatial distribution characteristics of noise within the acoustic metamaterial barrier are obtained by analysis. The noise measurement and analysis system performs spectrum analysis on the noise in the time domain to obtain the frequency domain characteristics of the noise, thereby obtaining the sound insulation frequency range of the noise at each rectangular through hole position of the metamaterial support bracket 7 . According to the principle that the optimal sound insulation frequency range is the same as the sound insulation frequency range of the rectangular through hole of the metamaterial support bracket, the fractal structure acoustic metamaterial module 8 is selected to be embedded in the rectangular through hole of the metamaterial support bracket 7, and the fractal structure acoustic For the acoustic metamaterial unit of the metamaterial module, its fractal order and acoustic waveguide width are the fractal order and acoustic waveguide width of the acoustic metamaterial unit corresponding to the fractal structure acoustic metamaterial unit in the same desired sound insulation frequency range as the optimal sound insulation frequency range. When the sound source changes, the spatial sound field changes, and the noise is measured by the noise measurement and analysis system 2 again. According to the changed sound field distribution, the fractal structure acoustic metamaterial module 8 at the position corresponding to the sound field change is disassembled and replaced with a Fractal structure acoustic metamaterial module 8 designed for sound field characteristics after change, Fractal structure acoustic metamaterial module designed for sound field characteristics after change The fractal order and acoustic waveguide width of the fractal structure acoustic metamaterial unit are required after the sound field changes Fractal order and acoustic waveguide width of the fractal structure acoustic metamaterial unit corresponding to the sound insulation frequency range. When the sound wave is transmitted to the acoustic metamaterial barrier 3, since the parameters of the fractal structure acoustic metamaterial module 8 are selected according to the noise distribution characteristics of the corresponding position, the amplitude of the sound wave in the target noise reduction area can be greatly reduced.

Claims (4)

1. An acoustic metamaterial barrier system for transformer noise spatial distribution characteristics, characterized by: the acoustic metamaterial barrier system is arranged on the outer side of an indoor transformer ventilation opening or on the periphery of an outdoor transformer and comprises an acoustic metamaterial barrier (3) and a noise measurement and analysis system (2);

the acoustic metamaterial barrier (3) is composed of a metamaterial supporting bracket (7) and a fractal structure acoustic metamaterial module (8), and the fractal structure acoustic metamaterial module (8) is embedded in the metamaterial supporting bracket (7);

when the acoustic metamaterial barrier (3) is established, the noise measurement and analysis system (2) measures the noise characteristics of the position of the acoustic metamaterial barrier (3), and selects the fractal order and the acoustic waveguide width parameter of the fractal structure acoustic metamaterial module (8) of the acoustic metamaterial barrier (3) according to the noise space distribution; when a sound source changes, a space sound field changes, the noise measurement and analysis system (2) measures noise again, the fractal order and the acoustic wave guide width parameter of the fractal structure acoustic metamaterial module (8) of the acoustic metamaterial barrier are adjusted according to the changed sound field distribution, and the fractal structure acoustic metamaterial module (8) of the acoustic metamaterial barrier after the parameters are adjusted is used for replacing the previous fractal structure acoustic metamaterial module (8);

the metamaterial support bracket (7) is of a cuboid structure and is arranged in parallel with the transformer sound source surface (1), and a distance is reserved between the metamaterial support bracket and the transformer sound source surface; one surface of the metamaterial supporting bracket (7) opposite to the transformer sound source surface (1) is provided with m x n rectangular through holes, and m and n are positive integers; the rectangular through holes are the same in size and are arranged at equal intervals to form an array;

the fractal structure acoustic metamaterial module (8) is made of epoxy resin materials and is embedded in the rectangular through holes of the metamaterial supporting bracket (7), and the acoustic metamaterial module (8) in each rectangular through hole can be detached.

2. The acoustic metamaterial barrier system of claim 1, wherein: the fractal structure acoustic metamaterial module (8) is of a cuboid structure with an acoustic wave guide and a bottom plate, the bottom plate is positioned at the bottom of the cuboid structure, and the acoustic wave guide is fixed on the bottom plate; air circulates along the acoustic wave guide in the fractal structure acoustic metamaterial module (8);

the fractal structure acoustic metamaterial module (8) consists of a fractal structure acoustic metamaterial unit array; the cross section of the acoustic metamaterial unit is a rectangular surface with a Hilbert curve-shaped channel with a certain width; the order of the fractal structure acoustic metamaterial unit and the width of the acoustic wave guide are related to the sound insulation frequency;

establishing a fractal structure acoustic metamaterial unit model, giving the order of an acoustic metamaterial unit and the parameter range of waveguide width, scanning the waveguide width parameter of the acoustic metamaterial module under the given order, and obtaining the sound insulation quantity of the acoustic metamaterial unit with the given order and the waveguide width at different frequencies through sound field calculation; the frequency range with high sound insulation amount is the optimal sound insulation frequency range of the acoustic metamaterial unit with given parameters; and selecting the fractal order and the width of the wave guide of the fractal structure acoustic metamaterial unit of the acoustic metamaterial unit corresponding to the sound insulation frequency range according to the optimal sound insulation frequency range.

3. The acoustic metamaterial barrier system of claim 1, wherein: the noise measurement and analysis system (2) is composed of a sensor support bracket (4), a sound pressure sensor (5) and a sound pressure signal processing module (6); the sound pressure sensor (5) is arranged on the sensor support bracket (4), and the sound pressure signal processing module (6) is connected with the sound pressure sensor (5);

the sensor supporting bracket (4) is parallel to the metamaterial supporting bracket (7), is arranged near the metamaterial supporting bracket (7), and is positioned on the same side of the transformer as the metamaterial supporting bracket (7); the sensor supporting bracket (4) is of a cuboid structure, the height of the sensor supporting bracket is equal to that of the metamaterial barrier supporting bracket (7), and the width of the sensor supporting bracket is smaller than that of the metamaterial barrier supporting bracket (7); the sensor support bracket (4) comprises a plurality of cross beams and vertical beams, the cross beams and the vertical beams are crossed to form a plurality of rectangular through holes, the size of each rectangular through hole is the same, the length of each rectangular through hole is less than or equal to 1/2 of the length of each rectangular through hole of the metamaterial support bracket, and the width of each rectangular through hole is less than or equal to 1/2 of the width of each rectangular through hole of the metamaterial support bracket; the sensor support bracket is movable in a direction parallel to the acoustic metamaterial barrier;

the sound pressure sensor (5) is arranged at the intersection point of the cross beam and the vertical beam of the sensor support bracket (4) to form a sound pressure sensor array;

the sound pressure signal processing module (6) comprises a preamplifier, a filter, an A/D converter and a DSP processor; the input end of the preamplifier is connected with the sound pressure sensor (5) to amplify the noise signal collected by the sound pressure sensor; the input end of the filter is connected with the output end of the preamplifier, high-frequency components in noise signals collected by the sound pressure sensor are filtered, and collected sound pressure analog signals are sent to the A/D conversion module from the output end of the filter; the signal is sampled by the A/D converter and then is sent to the input end of the DSP processor, and the DSP processor carries out spectrum analysis and interpolation calculation on the noise signal to obtain the noise distribution characteristic and the spectrum characteristic within the range of the sensor support bracket.

4. The acoustic metamaterial barrier system of claim 1, wherein: the sensor support bracket (4) is aligned with the outer vertical beam of the metamaterial support bracket (7); the noise measurement and analysis system (2) measures noise distribution, after the measurement is finished, the distance between the sensor support bracket (4) and the metamaterial support bracket (7) is kept unchanged, and the noise measurement and analysis system (2) is moved to measure the noise distribution of the next area until the measurement range covers the whole metamaterial barrier (3); the noise measurement and analysis system carries out spectrum analysis on the noise in a time domain to obtain the frequency domain characteristic of the noise, so that the sound insulation frequency range of the noise at each rectangular through hole position of the metamaterial support bracket (7) is obtained, and a fractal structure acoustic metamaterial module (8) is selected to be embedded into the rectangular through hole of the metamaterial support bracket (7) according to the principle that the optimal sound insulation frequency range is the same as the sound insulation frequency range at the rectangular through hole position of the metamaterial support bracket; the fractal order and the sound wave guide width of the acoustic metamaterial unit of the fractal structure (8) are the fractal order and the sound wave guide width of the acoustic metamaterial unit of the fractal structure corresponding to the required sound insulation frequency range which is the same as the optimal sound insulation frequency range; when a sound source changes, the spatial distribution of noise changes, the noise is measured again through a noise measurement and analysis system, a fractal structure acoustic metamaterial module (8) corresponding to the position where the sound field changes is disassembled according to the changed sound field distribution, and the fractal structure acoustic metamaterial module is replaced by the fractal structure acoustic metamaterial module (8) designed according to the characteristics of the sound field after the sound field changes; the fractal order and the width of the wave guide of the fractal structure acoustic metamaterial unit in the fractal structure acoustic metamaterial module (8) designed according to the characteristics of the changed sound field are the fractal order and the width of the wave guide of the fractal structure acoustic metamaterial unit corresponding to the required sound insulation frequency range after the sound field is changed.

Images