CN109148123B - Acoustic metamaterial barrier system for transformer noise spatial distribution characteristics - Google Patents
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Abstract
An adjustable acoustic metamaterial barrier system aiming at the spatial distribution characteristic of transformer noise is composed of an acoustic metamaterial barrier (3) and a noise measurement analysis system (2). The acoustic metamaterial barrier (3) is composed of a metamaterial supporting bracket (7) and a fractal structure acoustic metamaterial module (8). The metamaterial support bracket (7) is parallel to the transformer sound source surface (1). The fractal structure acoustic metamaterial module (8) is embedded in the metamaterial supporting bracket (4). The noise measurement and analysis system (2) measures noise in the range of the acoustic metamaterial barrier (3) and analyzes to obtain the noise spatial distribution characteristic. And selecting fractal structure acoustic metamaterial modules (8) with different parameters according to the noise space distribution characteristics. When sound waves are transmitted to the acoustic metamaterial barrier (3), the noise amplitude of the target noise reduction area can be greatly reduced due to the fact that parameters of the acoustic metamaterial module (8) are selected according to the noise distribution characteristics of the corresponding position.
Description
Technical Field
The invention relates to an acoustic metamaterial barrier.
Background
The noise of the transformer body mainly comes from the vibration of an iron core and a winding, the noise is concentrated on the frequency multiplication of 100Hz, and the low-frequency noise is taken as the main noise. The noise of the transformer fan is broadband noise between 500 and 2000 Hz. Along with the construction of cities, a large number of 110kV and 220kV transformer substations are closer to central urban areas. The noise propagation environment is complex, the noise problem of the transformer is increasingly prominent due to the interference, diffraction and other effects of the sound waves, and the influence on workers in the station and nearby residents is inevitable. Therefore, how to control the transformer noise in the transmission path has become an important issue to be solved urgently in the environmental protection department and the power department.
At present, the noise reduction method for the transformer noise mainly comprises the following steps: active noise reduction and material noise reduction. Active noise reduction, i.e. active noise reduction, is disclosed in chinese patent CN106251855A, "a non-centralized virtual sound barrier for transformer noise reduction", where an active sound barrier is installed near an opening surface of a room, and is composed of a control sound source, an error microphone, a reference sensor, a plurality of single-channel active controllers and a peripheral circuit, and can control the noise radiated from the sound source in the room through the opening. The active sound barrier has the advantage of flexible control and the disadvantage of great difficulty in control when the number of arrays is increased.
The noise of the transformer body is mainly low-frequency noise, and the noise reduction effect of the sound barrier made of the traditional sound insulation material on the low-frequency noise is poor. The acoustic metamaterial has extraordinary physical characteristics such as negative refraction, strong reflection, negative mass density and negative volume modulus, has the advantages of large sound insulation amount, small thickness and the like compared with the traditional material, can realize the control of low-frequency noise by the small-sized material, effectively makes up the defect that the barrier of the traditional material is difficult to block the low-frequency noise, and has good development prospect in the field of transformer noise reduction. The sound barrier disclosed in chinese patent CN106192785A full band noise reduction barrier and shielding device for transformer substation includes a metamaterial low frequency noise reduction layer and a high frequency noise reduction layer, which are disposed near a transformer to reduce full band noise on a noise propagation path of the transformer. The acoustic metamaterial barrier disclosed by the patent does not consider the difference of noise space distribution, and once the acoustic metamaterial barrier is established, the acoustic metamaterial barrier cannot be flexibly adjusted according to the distribution change of a space sound field, so that the noise reduction effect is poor.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an acoustic metamaterial barrier system aiming at the noise spatial distribution characteristic of a transformer.
The acoustic metamaterial barrier system comprises an acoustic metamaterial barrier and a noise measurement and analysis system, and is arranged on the outer side of an indoor transformer ventilation opening or on the periphery of an outdoor transformer.
The acoustic metamaterial barrier is composed of a metamaterial supporting bracket and a fractal structure acoustic metamaterial module, and the fractal structure acoustic metamaterial module is embedded into the metamaterial supporting bracket.
When the acoustic metamaterial barrier is established, the noise measurement and analysis system measures the noise characteristics of the acoustic metamaterial barrier, and selects the fractal order and the acoustic waveguide width parameter of each fractal structure acoustic metamaterial module of the acoustic metamaterial barrier according to the noise space distribution. When the sound source changes, the space sound field changes, the noise is measured through the noise measurement and analysis system again, the fractal order and the acoustic wave guide width parameter of each fractal structure acoustic metamaterial module of the acoustic metamaterial barrier are adjusted according to the changed sound field distribution, and the fractal structure acoustic metamaterial module of the acoustic metamaterial barrier after the parameters are adjusted is used for replacing the previous fractal structure acoustic metamaterial module.
The metamaterial support bracket is a cuboid. The transformer has four directional outer contour surfaces except for the top and bottom surfaces. The outer contour plane defining any one direction is the transformer sound source plane. The transformer sound source surface is parallel to the metamaterial support bracket, and a certain distance is reserved between the transformer sound source surface and the metamaterial support bracket. One surface of the metamaterial supporting bracket, which is opposite to the sound source surface of the transformer, is provided with m multiplied by 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 is embedded in the rectangular through holes of the metamaterial support bracket, and the fractal structure acoustic metamaterial module in each rectangular through hole can be detached. The fractal structure acoustic metamaterial module is parallel to a transformer sound source surface, the surface close to the transformer sound source surface is a sound wave inlet surface, and the surface far away from the transformer sound source surface is a sound wave outlet surface. And the surface vertical to the sound wave inlet surface and the sound wave outlet surface is the cross section of the fractal structure acoustic metamaterial module.
The fractal structure acoustic metamaterial module is an array formed by fractal structure acoustic metamaterial units. The cross section of the acoustic metamaterial unit is a rectangular surface with a Hilbert curve-type channel with a certain width. A Hilbert curved channel of a certain width is called a sonic wave guide.
The sound insulation frequency of the fractal structure acoustic metamaterial unit is closely related to the fractal order and the width of the acoustic wave guide.
Establishing a fractal structure acoustic metamaterial unit model, giving parameter ranges of fractal orders and waveguide widths of the acoustic metamaterial units, performing waveguide width parameter scanning under the given fractal orders, and obtaining sound insulation of the acoustic metamaterial units with the given orders and the waveguide widths at different frequencies through sound field calculation.
And (3) calculating the sound pressure of the measurement point according to the structural field and sound field coupling equation (1) and the sound pressure fluctuation equation (2).
Where ρ is0For mass density, v is vibration velocity, p is sound pressure, c is sound velocity, ▽ is hamiltonian.
Where ρ is0For mass density, p is sound pressure, c is sound velocity, ▽ is Hamiltonian, and t is sound wave propagation time.
From the sound pressure, the sound pressure level can be obtained:
wherein p is sound pressure, prefFor reference sound pressure, internationally taken as 2 × 10-5Pa, SPL is sound pressure level, and the sound insulation quantity is obtained according to the sound pressure level:
TL＝SPL2-SPL1(4)
wherein, SPL2For measuring the sound pressure level, SPL, of a point location when adding a metamaterial unit1TL is the sound insulation quantity for measuring the sound pressure level of the point position after the metamaterial unit is added.
The frequency range with high sound insulation is the optimal sound insulation frequency range of the acoustic metamaterial unit with given parameters. And selecting the fractal order and the acoustic waveguide width of the given fractal structure acoustic metamaterial unit corresponding to the sound insulation frequency range according to the optimal sound insulation frequency range.
Air circulates along the acoustic wave guide in the fractal structure acoustic metamaterial unit.
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 arranged 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 positioned on the same side of the transformer as the metamaterial support bracket. The sensor support bracket is of a cuboid structure, the height of the sensor support bracket is equal to that of the metamaterial barrier support bracket, and the width of the sensor support bracket is smaller than that of the metamaterial barrier support bracket. The sensor support bracket comprises a plurality of cross beams and vertical beams, wherein 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 smaller 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 smaller 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 is arranged at the intersection point of the cross beam and the vertical beam of the sensor support bracket to form a sound pressure sensor array.
The sound pressure signal processing module 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, and a noise signal acquired by the sound pressure sensor is amplified; 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 converter from the output end of the filter; the signal is sampled by an A/D converter and then is sent to the input end of a DSP processor; and the DSP processor performs interpolation calculation and spectrum analysis on the noise signals to obtain the noise distribution characteristic and the spectrum characteristic within the range of the sensor support bracket.
The working process of the invention is as follows: the sensor support bracket and the metamaterial support bracket are arranged in parallel with a small spacing distance, and the sensor support bracket is aligned with the outer vertical beam of the metamaterial support bracket. And the noise measurement and analysis system measures and records noise, after the measurement is finished, the distance between the sensor support bracket and the metamaterial support bracket is kept unchanged, and the noise measurement and analysis system is moved to measure the noise distribution of the next area until the measurement range covers the whole acoustic metamaterial barrier. And analyzing to obtain the noise spatial distribution characteristic in the range of the acoustic metamaterial barrier. The noise measurement and analysis system carries out spectrum analysis on the noise in the time domain to obtain the frequency domain characteristics of the noise, so that the sound insulation frequency range of each rectangular through hole of the metamaterial support bracket is obtained. And selecting a fractal structure acoustic metamaterial module to be embedded into the rectangular through hole 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 fractal order and the sound wave guide width of the acoustic metamaterial unit of the fractal structure acoustic metamaterial module are the fractal order and the sound wave guide width of the acoustic metamaterial unit of the fractal structure corresponding to the sound insulation frequency range which is the same as the optimal sound insulation frequency range. When a sound source changes, the spatial distribution of the noise changes, the noise is measured again through the noise measurement and analysis system, the fractal structure acoustic metamaterial module corresponding to the position where the sound field changes is detached according to the changed sound field distribution, the fractal structure acoustic metamaterial module is replaced by the fractal structure acoustic metamaterial module designed according to the sound field characteristics after the sound field changes, and the fractal order and the waveguide width of the fractal structure acoustic metamaterial unit of the fractal structure acoustic metamaterial module designed according to the sound field characteristics after the sound field changes are the fractal order and the waveguide width of the fractal structure acoustic metamaterial unit corresponding to the sound insulation frequency range after the sound field changes.
When sound waves are transmitted to the acoustic metamaterial barrier, the acoustic wave amplitude of the target noise reduction area can be greatly reduced due to the fact that parameters of the fractal structure acoustic metamaterial module are selected according to the noise distribution characteristics of the corresponding position.
The adjustable acoustic metamaterial barrier is established aiming at the spatial distribution characteristic of the transformer noise, so that the transformer noise can be effectively blocked on a transmission path, and the environmental noise pollution is reduced. Compared with the traditional sound barrier, when the barrier is established, the adjustable acoustic metamaterial barrier system disclosed by the invention selects the parameters of the acoustic metamaterial module with the parting structure according to the actually measured sound field distribution, so that the noise reduction effect can be improved; meanwhile, when the noise spatial distribution changes, the acoustic metamaterial module can be adjusted according to the actually measured noise distribution, and the flexibility of the sound barrier is improved.
Drawings
FIG. 1 is a schematic view of an adjustable acoustic metamaterial barrier system of the present invention;
FIG. 2 is a side view of the tunable acoustic metamaterial barrier system of the present invention;
FIG. 3 is a front view of the noise measurement analysis system of the present invention;
FIG. 4 is a front view of an acoustic metamaterial barrier of the present invention;
FIG. 5 is a block diagram of an acoustic pressure signal processing module according to the present invention;
FIG. 6 is a cross-sectional view of an acoustic metamaterial unit of the present invention.
In the figure: the system comprises a transformer sound source surface 1, a noise measurement and analysis system 2, an acoustic metamaterial barrier 3, a sensor supporting bracket 4, a sound pressure sensor 5, a sound pressure signal processing module 6, a metamaterial supporting bracket 7, a fractal structure acoustic metamaterial module 8, a preamplifier 9, a filter 10, an 11A/D converter, a DSP 12, a first-order fractal structure acoustic metamaterial unit cross section 13, a second-order fractal structure acoustic metamaterial unit cross section 14, a third-order fractal structure acoustic metamaterial unit cross section 15 and a fourth-order fractal structure acoustic metamaterial unit cross section 16.
Detailed Description
The invention is further described below with reference to the accompanying drawings and the detailed description.
As shown in fig. 1 and fig. 2, the adjustable acoustic metamaterial barrier system for transformer noise spatial distribution characteristics according to the present invention is disposed outside an indoor transformer ventilation opening or around an outdoor transformer, and includes 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 cuboid. The transformer has four directional outer contour surfaces except for the top and bottom surfaces. The outer contour plane defining any one direction is the transformer sound source plane. The transformer sound source surface 1 is parallel to the metamaterial support bracket 7, and a certain distance is reserved between the transformer sound source surface and the metamaterial support bracket 7. One surface of the metamaterial support bracket 7, which is opposite to the transformer sound source surface 1, is provided with m × 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 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 detached and replaced. The fractal structure acoustic metamaterial module 8 is parallel to the transformer sound source surface 1, the surface close to the transformer sound source surface is a sound wave inlet surface, and the surface far away from the transformer sound source surface 1 is a sound wave outlet surface. And the surface vertical to the sound wave inlet surface and the sound wave outlet surface is the cross section of the fractal structure acoustic metamaterial module 8.
The fractal structure acoustic metamaterial module 8 is an array formed by fractal structure acoustic metamaterial units. The cross section of the fractal structure acoustic metamaterial unit is a rectangular surface with a Hilbert curve-shaped channel with a certain width, as shown in FIG. 6. The fractal structure acoustic metamaterial unit can be in a first-order 13, a second-order 14, a third-order 15 or a fourth-order 16 in cross section. The order of the fractal structure acoustic metamaterial unit and the width of the acoustic wave guide are closely related to the sound insulation frequency.
Establishing a fractal structure acoustic metamaterial unit model, giving parameter ranges of fractal orders and waveguide widths of the acoustic metamaterial units, performing waveguide width parameter scanning under the given fractal orders, and obtaining sound insulation of the acoustic metamaterial units with the given orders and the waveguide widths at different frequencies through sound field calculation.
And (3) calculating the sound pressure of the measurement point according to the structural field and sound field coupling equation (1) and the sound pressure fluctuation equation (2).
Where ρ is0For mass density, v is vibration velocity, p is sound pressure, c is sound velocity, ▽ is hamiltonian.
Where ρ is0For mass density, p is sound pressure, c is sound velocity, ▽ is Hamiltonian, and t is sound wave propagation time.
From the sound pressure, the sound pressure level can be obtained:
wherein p is sound pressure, prefFor reference sound pressure, internationally taken as 2 × 10-5Pa, SPL is sound pressure level, and the sound insulation quantity is obtained according to the sound pressure level:
TL＝SPL2-SPL1(4)
wherein, SPL2For measuring the sound pressure level, SPL, of a point location when adding a metamaterial unit1TL is the sound insulation quantity for measuring the sound pressure level of the point position after the metamaterial unit is added.
The frequency range with high sound insulation is the optimal sound insulation frequency range of the acoustic metamaterial unit with given parameters. And selecting the fractal order and the acoustic waveguide width of the given fractal structure acoustic metamaterial unit corresponding to the same sound insulation frequency range according to the optimal sound insulation frequency range.
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. A front view of the sensor support bracket 4 and the acoustic 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 positioned on the same side of the transformer as the metamaterial support bracket 7. The sensor support bracket 4 is a cuboid, the height of the sensor support bracket is equal to that of the metamaterial support bracket 7, and the width of the sensor support bracket is smaller than that of the metamaterial support bracket 7. The sensor support bracket 4 comprises a plurality of cross beams and vertical beams, wherein 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 smaller 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 smaller than or equal to 1/2 of the width of each rectangular through hole of the metamaterial support bracket. The sensor support 4 is movable in a direction parallel to the metamaterial support 7.
And 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 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 with 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 with the output end of the preamplifier 9, so as to filter high-frequency components in the noise signal acquired by the sound pressure sensor 5, and the acquired sound pressure analog signal is sent to the A/D converter 11 from the output end of the filter 10; the signals are sent to the input end of the DSP 12 after being subjected to A/D sampling, and the DSP 12 performs spectrum analysis and interpolation calculation on the noise signals to obtain noise distribution and spectrum characteristics within the range of the acoustic metamaterial barrier 3.
The working process of the invention is as follows: the sensor support bracket 4 and the metamaterial support bracket 7 are arranged in parallel with a small spacing distance, and the outer vertical beams of the two brackets are aligned. And the noise measurement and analysis system 2 measures and records noise, 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 is moved to measure the noise distribution of the next area until the measurement range covers the whole acoustic metamaterial barrier 3. And analyzing to obtain the noise spatial distribution characteristic in the range of the acoustic metamaterial barrier. The noise measurement and analysis system carries out spectrum analysis on the noise in the time domain to obtain the frequency domain characteristics of the noise, so that the sound insulation frequency range of the noise at each rectangular through hole of the metamaterial support bracket 7 is obtained. 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 into the rectangular through hole of the metamaterial support bracket 7, and the fractal order and the sound wave waveguide width of the acoustic metamaterial unit of the fractal structure acoustic metamaterial module are the fractal order and the sound wave waveguide width of the fractal structure acoustic metamaterial unit corresponding to the required sound insulation frequency range which is the same as the optimal sound insulation frequency range. When a sound source changes, a space sound field changes, noise is measured through the noise measurement and analysis system 2 again, the fractal structure acoustic metamaterial module 8 corresponding to the position where the sound field changes is detached according to the changed sound field distribution, the fractal structure acoustic metamaterial module 8 is replaced by the fractal structure acoustic metamaterial module 8 designed according to the changed sound field characteristic, and the fractal order and the waveguide width of the fractal structure acoustic metamaterial unit of the fractal structure acoustic metamaterial module designed according to the changed sound field characteristic are the fractal order and the waveguide width of the fractal structure acoustic metamaterial unit corresponding to the required sound insulation frequency range after the sound field changes. When the sound wave is transmitted to the acoustic metamaterial barrier 3, the acoustic wave amplitude of the target noise reduction area can be greatly reduced because the parameters of the fractal structure acoustic metamaterial module 8 are selected according to the noise distribution characteristics of the corresponding position.
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.
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