CN118116356A - Low-frequency sound insulation unit with adjustable frequency band and application thereof - Google Patents
Low-frequency sound insulation unit with adjustable frequency band and application thereof Download PDFInfo
- Publication number
- CN118116356A CN118116356A CN202410421933.1A CN202410421933A CN118116356A CN 118116356 A CN118116356 A CN 118116356A CN 202410421933 A CN202410421933 A CN 202410421933A CN 118116356 A CN118116356 A CN 118116356A
- Authority
- CN
- China
- Prior art keywords
- sound insulation
- low
- frequency
- cavity
- resonant cavity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000009413 insulation Methods 0.000 title claims abstract description 216
- 238000004804 winding Methods 0.000 claims abstract description 78
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 claims abstract description 6
- 238000009423 ventilation Methods 0.000 claims description 86
- 230000004888 barrier function Effects 0.000 claims description 80
- 239000002131 composite material Substances 0.000 claims description 45
- 239000010410 layer Substances 0.000 claims description 33
- 239000002356 single layer Substances 0.000 claims description 26
- 239000011347 resin Substances 0.000 claims description 3
- 229920005989 resin Polymers 0.000 claims description 3
- 238000002788 crimping Methods 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- 238000002834 transmittance Methods 0.000 description 34
- 238000010586 diagram Methods 0.000 description 21
- 238000004088 simulation Methods 0.000 description 18
- 238000005259 measurement Methods 0.000 description 13
- 238000010521 absorption reaction Methods 0.000 description 10
- 230000008859 change Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000002310 reflectometry Methods 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 2
- 150000001875 compounds Chemical group 0.000 description 2
- 230000001808 coupling effect Effects 0.000 description 2
- 230000001755 vocal effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000030279 gene silencing Effects 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009323 psychological health Effects 0.000 description 1
- 230000008844 regulatory mechanism Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003911 water pollution Methods 0.000 description 1
Landscapes
- Building Environments (AREA)
Abstract
The invention discloses a low-frequency sound insulation unit with adjustable frequency band and application thereof, wherein the low-frequency sound insulation unit comprises a first resonant cavity and a second resonant cavity which are mutually adjacent in the x direction and have the same structure, and two cover plates positioned at two ends of the first resonant cavity and the second resonant cavity in the z direction, wherein the first resonant cavity and the second resonant cavity respectively comprise a rectangular cavity positioned in the middle, a first curling channel and a second curling channel which are respectively positioned at the left side and the right side of the rectangular cavity and are symmetrically arranged, the rectangular cavity is a drawer-type frame which is formed by nesting a U-shaped first frame and a U-shaped second frame with opposite openings, and a cavity inlet is arranged on one side wall of the first frame opposite to the openings; the first winding channel and the second winding channel are communicated at the inlet of the cavity; the first and second serpentine channels each have a plurality of serpentine bends. The length and the width of the low-frequency sound insulation unit have deep sub-wavelength characteristics, and have good sound insulation performance; the resonant frequency can also be adjusted by adjusting the size of d.
Description
Technical Field
The invention relates to the field of noise control, in particular to a low-frequency sound insulation unit with an adjustable frequency band and application thereof.
Background
Noise pollution, atmospheric pollution and water pollution are parallel to three pollution in the world. Noise control has been one of the key directions of research in the acoustic field. In industrial production, noise generated by a power system of mechanical equipment, machine body vibration, aerodynamic force and the like is low in frequency and high in strength, and can cause non-negligible harm to physical and psychological health of instruments and equipment and operators. The low-frequency sound insulation method which is effective in general is to manufacture various sound insulation covers by adopting traditional sound attenuation and sound insulation materials. However, such low frequency sound-insulating covers have problems of large size and high density based on mass density law. Meanwhile, the sealing characteristic of the traditional sound insulation cover also enables heat generated by mechanical equipment to be unable to spread, so that the operation efficiency of the equipment is affected.
In recent years, the development of acoustic metamaterials has provided a variety of new ideas for solving the above problems. The acoustic metamaterial has the advantages of small size, openness and easiness in regulation and control, and is widely applied to the design and preparation of various silencing and sound-insulating devices. For example, good low-frequency sound absorption performance can be achieved based on a Helmholtz resonator, a spiral space resonance structure, a ring resonance cavity structure with cracks, a super-surface sound absorption structure, an elastic film composite structure and the like. However, such designs have a relatively high tightness and cannot be applied to special application situations requiring ventilation and heat dissipation. In order to solve the problem, researchers at home and abroad propose various open type low-frequency sound absorption structures with ventilation performance. The acoustic impedance matching realized on the basis of the coupling effect of the asymmetric acoustic super surface can realize low-frequency acoustic energy absorption in the pipeline, and meanwhile, the air circulation is not influenced; based on the weak coupling effect between two identical tubular resonant cavities with gaps, the low-frequency ventilation and sound absorption effect can be realized. In addition, a multi-layer sparse barrier structure is designed based on a composite unit formed by Helmholtz resonators, so that a low-frequency ventilation and sound insulation effect with a certain bandwidth can be realized.
However, the structure of the sound insulation device is fixed, and a related performance quantitative regulation mechanism is not yet available. In some practical scenarios, the noise signal frequency of the mechanical device will change with changes in the environment. In this case, the design of the sound insulation unit having the low-frequency sound insulation band-adjustable function is important.
Disclosure of Invention
In order to realize a low-frequency adjustable ventilation and sound insulation device, the invention provides a low-frequency sound insulation unit with adjustable frequency band and application thereof, wherein the length and width of the low-frequency sound insulation unit have the characteristic of depth sub-wavelength, and the low-frequency sound insulation unit has good sound insulation performance in a low-frequency range; simultaneously, d can be adjusted by pulling the drawer-type frame so as to adjust the size of the rectangular cavity, and further the resonant frequency of the low-frequency sound insulation unit can be adjusted, so that the central working frequency of the sound insulation barrier is adjusted and controlled; in addition, the low frequency sound insulation unit exhibits good ventilation performance when used in a sound insulation barrier.
The technical scheme adopted by the invention is as follows:
The utility model provides a low frequency sound insulation unit with adjustable frequency band, includes that first resonant cavity and second resonant cavity that are arranged closely each other and the structure is the same in the x direction to and two apron at first resonant cavity and second resonant cavity z direction both ends, first resonant cavity and second resonant cavity all include the rectangle cavity that is located the centre, and the first spiral passageway and the second spiral passageway that just set up symmetrically in rectangle cavity left and right sides respectively, but rectangle cavity is by the first frame of "U" shape, the second frame opening relative nested pull drawer type frame that forms, be provided with the cavity entry on the first frame and the opposite lateral wall of opening; the first winding channel and the second winding channel are communicated at the inlet of the cavity and are relatively fixed with the position of the first frame; the first and second serpentine channels each have a plurality of serpentine bends, and the vocal tract inlets of the first and second serpentine channels are in the y-direction; and the inlet directions of sound channels and the inlet directions of cavities on the first resonant cavity and the second resonant cavity are opposite.
Further, the lengths of the first resonant cavity and the second resonant cavity are a, the thicknesses of the winding channel walls of the first winding channel and the second winding channel are e=0.02a, the widths of the first winding channel and the second winding channel are t=0.06a, the width t 1 of the cavity entrance is=0.06a, the length d of the drawer-type frame drawn by the second frame is in the range of 0-d-50 mm, and the lengths of the outer side walls of the channel entrances of the first winding channel and the second winding channel are a; preferably, the a=100 mm.
Furthermore, the low-frequency sound insulation unit is made of organic glass or resin; the number of serpentine bends of the first and second serpentine channels is not less than two.
The low-frequency sound insulation unit is used for isolating ventilation type low-frequency noise in building space or equipment, and the working frequency band range is 120-170Hz.
A single layer low frequency ventilation type sound insulation barrier, characterized in that: the low-frequency sound insulation units are arranged at intervals along the x direction, the parameters of the low-frequency sound insulation units are the same, the interval distance between the adjacent low-frequency sound insulation units is L, and the length d of the drawer-type frame drawn out by the second frame in the drawer-type frame is more than or equal to 0 and less than or equal to 50mm.
Further, the center-to-center distance between two adjacent low-frequency sound insulation units is l=400 mm.
A double-deck low frequency ventilation formula sound insulation barrier, its characterized in that: the two low-frequency sound insulation units are arranged at intervals along the y direction to form a composite unit, and a plurality of composite units are arranged at intervals along the x direction to form a double-layer low-frequency ventilation type sound insulation barrier; the distance H 1 between the centers of two low-frequency sound insulation units in the composite unit is 150mm, and the distance L 1 between the centers of two adjacent composite units is 400mm; the length d of the drawer-type frame drawn out of the second frames of the first resonant cavity and the second resonant cavity in the composite unit is more than or equal to 0 and less than or equal to 50mm.
Further, the lengths d of the drawer-type frames drawn out by the second frames in the four resonant cavities in the composite unit are not completely the same, and other parameters are the same.
A complicated double-deck broadband ventilation formula sound barrier, its characterized in that: the two low-frequency sound insulation units are arranged next to each other along the x direction to form a unit group, the two unit groups are arranged at intervals along the y direction to form a composite unit III, a plurality of composite units III are arranged at intervals along the x direction to form a complex double-layer broadband ventilation type sound insulation barrier, the center-to-center distance of the two unit groups in the composite unit III is H 3 =150 mm, the center-to-center distance L 3 =600 mm of the adjacent composite units III, and the length d range of the drawer type frame drawn out by the second frames of the first resonant cavity and the second resonant cavity in the composite unit III is more than or equal to 0 and less than or equal to 50mm.
Further, the lengths d of the drawer-type frames drawn out by the second frames in the drawer-type frames in the eight resonant cavities in the composite unit III are not completely the same, and other parameters are the same.
The beneficial effects of the invention are as follows:
The low-frequency sound insulation unit can be used for designing a single-layer low-frequency ventilation type sound insulation barrier, when the parameter d=0mm, the sound energy transmittance is lower than-5 dB in the frequency band range of 151-158Hz, the maximum sound energy absorptivity can reach 0.65, the maximum sound energy reflectivity is about 0.3, the relative working bandwidth reaches 4.5%, and the high-frequency sound insulation performance is shown. At the moment, the length and the width of the low-frequency sound insulation unit respectively reach 0.09 lambda and 0.049lambda, and the low-frequency sound insulation unit has the characteristic of deep sub-wavelength and good sound insulation performance in a low-frequency range. And a certain distance is reserved between two adjacent low-frequency sound insulation units in the single-layer low-frequency ventilation type sound insulation barrier, so that good ventilation performance is shown while good low-frequency sound insulation performance is ensured, the barrier can be used for isolating ventilation type low-frequency noise in building space or equipment, and free circulation of air, light and heat at two sides of the barrier is realized.
The low-frequency sound insulation unit with the adjustable frequency band can be used for designing an adjustable ventilation type sound insulation barrier. D can be adjusted through the drawer type frame of pull in the low frequency sound insulation unit to adjust the size of rectangle cavity, and then can adjust the resonant frequency of low frequency sound insulation unit, thereby regulate and control the central operating frequency of sound barrier. When the distance d between the end of the drawer-type frame far away from the cavity entrance and the wall of the spiral channel is increased from 0mm to 47mm, the working frequency band of the adjustable ventilation type sound insulation barrier moves to a low frequency area, and the frequency corresponding to the lowest transmissivity is reduced from 155Hz to 122Hz. In particular, when the parameter d is selected to be 25mm, 35mm and 45mm, frequencies corresponding to the minimum values of the sound transmittance of the sound insulation barrier are 142Hz, 135Hz and 124Hz respectively, so that the low-frequency sound insulation performance with the adjustable working frequency band is realized by changing the parameter d.
The low-frequency sound insulation unit with the adjustable frequency band can be used for designing a double-layer low-frequency ventilation type sound insulation barrier. When the parameter d of the resonant cavity is 0mm, the acoustic energy transmittance of the double-layer low-frequency ventilation type sound insulation barrier is lower than-5 dB in the 149-164Hz frequency band range. When the parameters d of the four resonant cavities in the composite unit II are 0mm, 10mm, 20mm and 30mm in sequence along the inverted N shape, the acoustic energy transmittance of the double-layer low-frequency ventilation type sound insulation barrier is lower than-5 dB in the frequency band range of 136-158 Hz. When the parameter d is changed, the working frequency band and the working bandwidth of the double-layer low-frequency ventilation type sound insulation barrier are changed, and the low-frequency ventilation and sound insulation performance of the wide frequency band is flexible and adjustable.
The low-frequency sound insulation unit with the adjustable frequency band can be used for designing a complex double-layer broadband ventilation type sound insulation barrier, the sound insulation effect is good, when the distance d between one end of each of eight resonant cavities in the composite unit III, which is far away from a cavity inlet, and the wall of a spiral channel is along the reverse direction of the distance d, d1＝5mm、d2＝10mm、d3＝15mm、d4＝20mm、d5＝25mm、d6＝30mm、d7＝35mm、d8＝40mm, is in the frequency band range of 122-166Hz in sequence along the shape of N, the sound energy transmittance is lower than-5 dB, the relative bandwidth reaches 31%, in addition, the lowest sound transmittance is-16 dB, and the high-efficiency sound insulation effect is realized in a wider low-frequency range. Likewise, a certain distance exists between the adjacent composite units III, so that good ventilation performance is shown while good low-frequency sound insulation performance is ensured.
Drawings
Fig. 1 is a cross-sectional view of a band-adjustable low-frequency sound insulation unit according to an embodiment of the present invention.
Fig. 2 is a 3D printed sample diagram of the low-frequency sound insulation unit according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of an experimental measurement device for the sound insulation performance of the low-frequency sound insulation unit according to an embodiment of the invention.
Fig. 4 is a schematic diagram of measurement of the experimental measurement device according to an embodiment of the invention.
Fig. 5 is a schematic diagram of a single-layer low-frequency ventilation type sound insulation barrier based on the low-frequency sound insulation unit according to an embodiment of the present invention, wherein the schematic diagram of the low-frequency sound insulation unit is a cross-sectional view.
Fig. 6 is a graph showing the relationship between the transmittance of acoustic energy and the frequency of a single-layer low-frequency ventilation type sound insulation barrier according to an embodiment of the present invention.
Fig. 7 is a graph showing the relationship between the absorption rate, the reflection rate and the frequency of the acoustic energy of the single-layer low-frequency ventilation type sound insulation barrier according to the experimental measurement and the numerical simulation of the embodiment of the invention.
Fig. 8 is a graph showing the change of the sound energy transmittance of a single-layer low-frequency ventilation type sound insulation barrier of an adjustable low-frequency sound insulation unit based on different parameters d under the condition of numerical simulation of different frequencies according to the embodiment of the invention.
Fig. 9 is a graph showing the relationship between the transmittance of acoustic energy and the frequency of the ventilation type low frequency sound insulation barrier with different parameters d according to the second experimental measurement and numerical simulation of the second embodiment of the present invention.
Fig. 10 is a schematic diagram of a double-layer low-frequency ventilation type sound insulation barrier of the low-frequency sound insulation unit based on the same parameter d, wherein the schematic diagram of the low-frequency sound insulation unit is a sectional view.
FIG. 11 is a graph showing the relationship between the transmittance of acoustic energy and the frequency of the double-layer low-frequency ventilation type sound insulation barrier I according to the third embodiment of the present invention.
Fig. 12 is a schematic diagram of a second double-layer low-frequency ventilation type sound insulation barrier of a low-frequency sound insulation unit based on different parameters d, wherein the schematic diagram of the low-frequency sound insulation unit is a sectional view.
FIG. 13 is a graph showing the relationship between the transmittance of sound energy and the frequency of the second double-layer low-frequency ventilation type sound insulation barrier according to the third embodiment of the present invention.
Fig. 14 is a schematic diagram of a complex double-layer broadband ventilation type sound insulation barrier according to a fourth embodiment of the invention, wherein a schematic diagram of a low-frequency sound insulation unit is a sectional view.
FIG. 15 is a graph showing the relationship between the transmittance of sound energy and the frequency of the complex double-layer broadband ventilation type sound insulation barrier according to the fourth embodiment of the present invention.
Reference numerals illustrate:
1. The microphone comprises a first resonant cavity, a second resonant cavity, a rectangular cavity, 41, a first winding channel, 42, a second winding channel, 43, a sound channel inlet, 44, a cavity inlet, 5, winding channel walls, 6, a drawer type frame, 61, a first frame, 62, a second frame, 7, a cover plate, 81, a computer, 82, a data controller, 83, a power amplifier, 84, a sound source, 85, a waveguide tube, 86 and a miniature microphone.
Detailed Description
The present invention will be described in further detail with reference to the drawings, but the scope of the invention is not limited thereto.
Example 1
As shown in fig. 1 and 2, the low-frequency sound insulation unit with adjustable frequency band according to the invention comprises a first resonant cavity 1 and a second resonant cavity 2 which are mutually adjacent in the x direction and have the same structure, two cover plates 7 positioned at two ends of the first resonant cavity 1 and the second resonant cavity 2 in the z direction, wherein the first resonant cavity 1 and the second resonant cavity 2 respectively comprise a rectangular cavity 3 positioned in the middle, a first curling channel 41 and a second curling channel 42 which are respectively positioned at the left side and the right side of the rectangular cavity 3 and are symmetrically arranged, the rectangular cavity 3 is formed by nesting a first frame 61 and a second frame 62 which are in a U shape, the openings of the first frame 61 and the second frame 62 are opposite, and a cavity inlet 44 is formed in one side wall opposite to the openings; the first and second crimping passages 41, 42 communicate at the cavity entrance 44 and are relatively fixed in position to the first frame 61; the first and second winding channels 41, 42 each have a plurality of serpentine bends, and the vocal tract inlets 43 of the first and second winding channels 41, 42 are in the y-direction; the directions of the sound channel inlets 43 and the cavity inlets 44 on the first resonant cavity 1 and the second resonant cavity 2 are opposite.
Fig. 2 is a 3D printed sample diagram of the low-frequency sound insulation unit, the lengths of the first resonant cavity 1 and the second resonant cavity 2 are a, and a=100 mm, so that the length of the low-frequency sound insulation unit is 2a=200 mm, and the height of the low-frequency sound insulation unit sample is 60mm. The thickness e of the winding channel wall 53 is 2mm, the width t of the first winding channel 41 and the width t of the second winding channel 42 are 6mm, the width t 1 of the cavity inlet 44 is 6mm, the length of the drawer-type frame 6 drawn by the second frame 62 in the drawer-type frame 6 is d, the size of the rectangular cavity 34 can be adjusted by drawing the size of the drawer-type frame 6, d is more than or equal to 0 and less than or equal to 50mm, the length of the outer side wall at the channel inlet 43 of the first winding channel 41 and the second winding channel 42 is a, the width of the first winding channel 41 and the second winding channel 2 is a+e+t+d= (108+d) mm, and the width of the low-frequency winding unit is a+e+t+2d= (108+2d) mm because the drawing directions of the second frame 62 of the first winding channel 1 and the second winding channel 2 are opposite, and the first winding channel 41 and the second winding channel 42 have two winding curves. The low-frequency sound insulation unit sample is made of photosensitive resin, and the material parameters are density 1180kg/m 3, longitudinal wave speed 2720m/s and transverse wave speed 1460m/s.
Fig. 3 is a schematic diagram of an experimental measurement device for the sound insulation performance of the band-adjustable low-frequency sound insulation unit. The experimental measurement device comprises a computer 81, a data controller 82, a power amplifier 83, a sound source 84, a waveguide 85 and a miniature microphone 86. The computer 81 is electrically connected with the data controller 82 to realize communication transmission of operation instructions and measurement data between the computer 81 and the data controller 82. The data controller 82 is electrically connected with the sound source 84 through the power amplifier 83, so that the data controller 82 outputs a sound source signal, and the power amplifier 83 drives the sound source 84 to excite and generate incident sound waves. The sound source 84 is disposed on the left side of the waveguide 85 for supplying experimental sound waves into the waveguide 85, and experimental measurement is performed in the waveguide 85, and the length, width and height dimensions of the waveguide 85 are 2m×0.4m×0.06m. The low frequency sound insulation unit sample is placed inside the waveguide 85 with the sound channel inlet 43 of one of the cavities facing the sound source 84. Four round holes with the same aperture and used for inserting miniature microphones 86 are formed in the top surface of the waveguide tube 85, and two miniature microphones 86 are respectively arranged at two ends of a low-frequency sound insulation unit sample and used for collecting sound wave signals. The miniature microphone 86 is connected with the data controller 82, sound wave signal data acquired by the miniature microphone 86 are transmitted to the computer 81 through the data controller 82, and the computer 81 processes the sound wave signal data to obtain sound energy transmission, absorption and reflection spectrograms of the ventilation type low-frequency sound insulation barrier.
Fig. 4 is a schematic diagram of measurement of the experimental measurement device, the computer 81 drives the sound source 84 to excite the sound signal in the waveguide 85 through the data controller 82 and the power amplifier 83 to be incident on the surface of the low-frequency sound insulation unit sample, the low-frequency sound insulation unit sample absorbs and reflects part of sound waves, another part of sound waves penetrate through the low-frequency sound insulation unit sample, and meanwhile, part of sound waves reflected by the right end of the waveguide exist in a transmission area on the right side of the low-frequency sound insulation unit sample. Four miniature microphones 86 on the waveguide 85 collect sound wave signals, the miniature microphone 86 on the left side of the low-frequency sound insulation unit sample, which is close to a sound source, is set to be a first miniature microphone, the miniature microphone 86 on the left side of the low-frequency sound insulation unit sample is set to be a second miniature microphone, the distance between the first miniature microphone and the second miniature microphone is s 1, and the distance between the second miniature microphone and the low-frequency sound insulation unit sample is l 1. The miniature microphone 86 on the right side of the low-frequency sound insulation unit sample, which is close to the sample, is a third miniature microphone, the miniature microphone 86 far away from the low-frequency sound insulation unit sample is a fourth miniature microphone, the distance between the third miniature microphone and the fourth miniature microphone is s 2, and the distance between the third miniature microphone and the low-frequency sound insulation unit sample is l 2. Let the incident and reflected acoustic signals on the left side of the low-frequency sound-insulation unit sample be p i and p r respectively, the transmitted and reflected acoustic signals on the right side of the low-frequency sound-insulation unit sample be p t and p tr respectively, and the acoustic signals detected by the first, second, third and fourth microphones are p 1、p2、p3 and p 4 respectively, then the acoustic signals detected by the fourth microphones 86 can be expressed as:
where e is a natural constant, i is an imaginary unit, k is the wave number in air, k=2pi/λ, and λ is the acoustic wave length.
The simultaneous formulas (1) and (2) can calculate that the incident sound wave signal p i and the reflected sound wave signal p r at the left side of the low-frequency sound insulation unit sample are respectively:
The reflection coefficient r can be calculated by combining the formulas (5) and (6):
Likewise, the transmitted acoustic signal p t on the right side of the low-frequency sound-insulating unit sample can be calculated by the simultaneous equations (3) and (4):
The transmission coefficient t can be calculated by combining equations (5) and (8):
By combining the formulas (7) and (9), the acoustic energy transmittance T, the reflectivity R and the absorptivity alpha of the low-frequency sound insulation unit sample can be calculated:
T＝t2 (10)
R＝r2 (11)
α＝1-r2 (12)
In this example the parameter is set to s 1＝s2＝10cm,l1＝l2 = 39.2cm.
Fig. 5 is a schematic diagram of a single-layer low-frequency ventilation type sound insulation barrier based on the low-frequency sound insulation units, wherein a plurality of low-frequency sound insulation units with the same parameters are arranged at intervals along the x direction to form the single-layer low-frequency ventilation type sound insulation barrier. The length d of the drawer-type frame 6 drawn out of the drawer-type frame 6 by the second frame 62 is d=0 mm, and the center-to-center distance between two adjacent low-frequency sound insulation units is l=400 mm. The sound wave is normally incident to the single-layer low-frequency ventilation type sound insulation barrier from bottom to top, namely, the sound wave is incident to the single-layer low-frequency ventilation type sound insulation barrier along the direction of the sound channel inlet 43 opposite to one of the resonant cavities.
A low-frequency sound insulation unit sample with the length of 2a=200 mm, the length of a=100 mm of the outer side wall at the sound channel inlet 43 of the first winding channel 41 and the second winding channel 42 and the height of 60mm is put into a waveguide tube 85, the length, width and height dimensions of the waveguide tube 85 are 2m multiplied by 0.4m multiplied by 0.06m, the height of the waveguide tube 85 is set to be the same as the height of the low-frequency sound insulation unit sample, and gaps are avoided between the low-frequency sound insulation unit sample and the upper and lower directions of the waveguide tube 85, so that experimental results are influenced; the width of the waveguide 85 is equal to the center-to-center distance between two adjacent low-frequency sound insulation units in the single-layer low-frequency ventilation type sound insulation barrier, which is equivalent to the experiment on a single-layer low-frequency ventilation type sound insulation barrier sample. The second frame 62 of the low-frequency sound-insulating unit sample drawer-type frame 6 is set to have a length d=0 mm to be drawn out of the drawer-type frame 6. The sound channel inlet 43 of one of the resonant cavities is opposite to the sound source 84, the frequency of the sound wave signal excited by the sound source 84 is changed, a plurality of points are uniformly taken within the range of 120-170Hz, the sound energy transmissivity, absorptivity and reflectivity of the single-layer low-frequency ventilation type sound insulation barrier sample under different frequencies are measured, and the environment parameters are that the density of air is 1.21kg/m 3 and the sound velocity is 343m/s in the experiment.
Meanwhile, the sound insulation performance of the single-layer low-frequency ventilation type sound insulation barrier is simulated through the Comsol software numerical value. Constructing a low-frequency sound insulation unit model with the length of a low-frequency sound insulation unit being 2a=200 mm, the width t of a first winding channel 41 and a second winding channel 42 being 6mm, the width t 1 of a cavity inlet 44 being 6mm, the thickness e of a winding channel wall 53 being 2mm, the length d of the drawer-type frame 6 drawn by a second frame 62 in the drawer-type frame 6 being d=0 mm, the length a=100 mm of the outer side wall at the sound channel inlet 43 of the first winding channel 41 and the second winding channel 42, and the material density being 1180kg/m 3, the longitudinal wave speed 2720m/s and the transverse wave speed 1460m/s, simulating the environment parameters being the density 1.21kg/m 3 of air, the sound speed 343m/s, the sound wave signal frequency being changed within the range of 120-170Hz, and calculating the sound energy transmittance, the sound absorption rate and the reflectivity of the single-layer low-frequency ventilation sound insulation barrier based on the low-frequency sound insulation unit at different frequencies.
Fig. 6 is a graph of acoustic energy transmittance versus frequency for a single layer low frequency ventilated sound barrier, measured experimentally and simulated numerically. It can be seen that the matching degree of the simulation data and the experimental data is good, the acoustic energy transmittance is lower than-5 dB in the frequency band range of 151-158Hz (black shadow area), the relative working bandwidth is F foc＝2(fH-fL)/(fH+fL) =2× (158-151)/(158+151) =4.5%, wherein F H and F L are the upper limit frequency and the lower limit frequency of the working frequency band respectively, the relative working bandwidth reaches 4.5%, and the better low-frequency sound insulation performance is shown. The transmittance of acoustic energy reaches the minimum at 155Hz, when the wavelength is Where v is the sound velocity 343m/s and f is the frequency. At this time, the length 2a=200 mm=0.09 λ and the width a+e+t+2d=108 mm=0.049λ of the low-frequency sound insulation unit, so that the low-frequency sound insulation unit has the characteristic of deep sub-wavelength, and can realize good sound insulation performance in a low-frequency range. In addition, the center distance L=400 mm between two adjacent low-frequency sound insulation units in the single-layer low-frequency ventilation type sound insulation barrier is twice as long as the length 2 a=200 mm of the low-frequency sound insulation units, so that good low-frequency sound insulation performance is ensured, and meanwhile, good ventilation performance is shown.
Fig. 7 is a graph of the change in acoustic energy absorption, reflectance and frequency of a single-layer low-frequency ventilated sound barrier measured experimentally and simulated numerically. It can be seen that the experimental measurement is well matched with the numerical simulation result, and the maximum acoustic energy absorptivity of the single-layer low-frequency ventilation type sound insulation barrier can reach 0.65 in the range of 151-158Hz frequency band (black shadow area), and the maximum acoustic energy reflectivity is about 0.3. The sound insulation effect of the designed ventilation type sound insulation barrier is obtained by absorbing and reflecting incident sound energy by the structure, and the sound energy absorption is mainly adopted.
Example two
The sound insulation performance of the single-layer low-frequency ventilation type sound insulation barrier is simulated through the numerical value of the Comsol software. A low-frequency sound insulation unit model was constructed with a low-frequency sound insulation unit length of 2a=200 mm, a width t of each of the first and second winding channels 41 and 42 of 6mm, a width t 1 of the cavity entrance 44 of 6mm, a thickness e of the winding channel wall 53 of 2mm, a length of the outer side wall at the channel entrance 43 of the first and second winding channels 41 and 42 of a =100 mm, and a material density of 1180kg/m 3, a longitudinal wave velocity of 2720m/s, a transverse wave velocity of 1460m/s, and a simulated environmental parameter of 1.21kg/m 3 of air, and a sound velocity of 343m/s. The frequency of the acoustic signal varies in the range of 120-170Hz, and the length d of the drawer-type frame 6 by which the second frame 62 is pulled out of the drawer-type frame 6 is adjusted to be increased from 0mm to 47mm by controlling the second frame 62 to be pulled out of the drawer-type frame 6. And numerically simulating the acoustic energy transmittance of the single-layer low-frequency ventilation type sound insulation barrier of the adjustable low-frequency sound insulation unit based on the different parameters d under different frequencies. Referring to fig. 8, as the parameter d increases, the operating frequency band of the ventilation type sound insulation barrier moves toward the low frequency region, and the frequency corresponding to the lowest acoustic energy transmittance decreases from 155Hz to 122Hz, thereby indicating that the operating frequency band of the ventilation type sound insulation barrier can be precisely controlled by changing the parameter d.
The low frequency sound insulation unit sample printed in the first embodiment was placed in the waveguide 85, wherein the second frame 62 was controlled to be drawn in the drawer-type frame 6 to adjust the lengths d of the drawer-type frame 6 where the second frame 62 was drawn out of the drawer-type frame 6 to be 25mm, 35mm and 45mm, respectively. The sound channel inlet 43 of one of the resonant cavities is opposite to the sound source 84, the frequency of the sound wave signal excited by the sound source 84 is changed, a plurality of points are uniformly acquired within the range of 120-170Hz, the sound energy transmittance of the low-frequency sound insulation unit sample is measured when the second frame 62 in the drawer-type frame 6 is pulled out of the drawer-type frame 6 with different frequencies and the lengths d of the second frame 62 are respectively 15mm, 25mm and 35mm, and a change relation diagram of the sound energy transmittance and the frequency of the ventilation type low-frequency sound insulation barrier sample with different parameters d is obtained, which is experimentally measured as shown in fig. 9. The environmental parameter in the experiment is that the density of air is 1.21kg/m 3 and the sound velocity is 343m/s.
Meanwhile, the sound insulation performance of the single-layer low-frequency ventilation type sound insulation barrier is simulated through the numerical value of the Comsol software. A low-frequency sound insulation unit model was constructed with a length of 2a=200 mm, a width t of each of the first and second winding channels 41 and 42 of 6mm, a width t 1 of the cavity inlet 44 of 6mm, a thickness e of the winding channel wall 53 of 2mm, a length a=100 mm of the outer side wall at the channel inlet 43 of the first and second winding channels 41 and 42, and a material density of 1180kg/m 3, a longitudinal wave velocity of 2720m/s, a transverse wave velocity of 1460m/s, and a simulated environmental parameter of 1.21kg/m 3 of air, and a sound velocity of 343m/s. The frequency of the sound wave signal is changed within the range of 120-170Hz, in addition, the length d of the second frame 62 drawn out of the drawer-type frame 6 in the drawer-type frame 6 is adjusted to be 25mm, 35mm and 45mm respectively by controlling the second frame 62 to be drawn out of the drawer-type frame 6, the sound energy transmittance under different parameters d and different frequencies is calculated in a simulation mode, and a graph of the change of the sound energy transmittance and the frequency of the ventilation type low-frequency sound insulation barrier of the adjustable low-frequency sound insulation unit with different parameters d, which is simulated in the numerical mode in FIG. 9, is obtained.
As can be seen from fig. 9, when the parameter d is selected to be 25mm, 35mm and 45mm, the frequencies corresponding to the minimum values of the acoustic energy transmittance are 142Hz, 135Hz and 124Hz respectively, which are consistent with the trend of the operating frequency band of the ventilation and sound insulation barrier in fig. 8, and the experimental measurement is consistent with the numerical simulation result. Based on the results, the designed ventilation type sound insulation barrier has good regulation and control performance in a low-frequency region, can be applied to special occasions with low-frequency noise frequency variation, and shows good practicability.
Example III
Fig. 10 is a schematic diagram of a double-layer low-frequency ventilation type sound insulation barrier of the low-frequency sound insulation unit based on the same parameter d. The two low-frequency sound insulation units with the same structure and parameters are arranged at intervals along the y direction to form a composite unit I, and the plurality of composite units I are arranged at intervals along the x direction to form a double-layer low-frequency ventilation type sound insulation barrier. The length of the low-frequency sound insulation unit is 2a=200mm, the width t of the first winding channel 41 and the second winding channel 42 is 6mm, the width t 1 of the cavity inlet 44 is 6mm, the thickness e of the winding channel wall 53 is 2mm, the length d of the drawer-type frame 6 drawn by the second frame 62 out of the drawer-type frame 6 is adjusted to be 0-d-50 mm, and the length a=100deg.C of the outer side wall at the sound channel inlet 43 of the first winding channel 41 and the second winding channel 42. And the center-to-center distance of two low-frequency sound insulation units in the composite unit I is H 1 =150 mm, and the center-to-center distance L 1 =400 mm of adjacent composite units I.
Numerical simulation is carried out through the Comsol software, a plurality of low-frequency sound insulation unit models with the length of2 a=200 mm, the widths t of the first winding channel 41 and the second winding channel 42 are 6mm, the width t 1 of the cavity inlet 44 is 6mm, the thickness e of the winding channel wall 53 is 2mm, the length a=100 mm of the outer side wall at the channel inlet 43 of the first winding channel 41 and the second winding channel 42, the material density is 1180kg/m 3, the longitudinal wave speed 2720m/s and the transverse wave speed 1460m/s are constructed, and the simulation environment parameters are the density of air 1.21kg/m 3 and the sound velocity 343m/s. And arranging the constructed low-frequency sound insulation units into a double-layer low-frequency ventilation type sound insulation barrier I according to the arrangement mode. The frequency of the sound wave signal is changed within the range of 110-180Hz, the length d of the second frame 62 in the drawer-type frame 6 drawn out of the drawer-type frame 6 is controlled to be d=0 mm, and the acoustic energy transmittance under different frequencies is calculated in a simulation mode, so that a graph of the acoustic energy transmittance and the frequency change of the double-layer low-frequency ventilation type acoustic barrier I in the simulation mode in FIG. 11 is obtained. It can be seen that in the 149-164Hz band range (black shaded area), the acoustic energy transmittance is below-5 dB. The operating bandwidth is twice that of the single-layer low-frequency ventilation type sound insulation barrier in the first embodiment. In addition, the center distance L 1 =400 mm between adjacent composite units I is 2 times of the length 2 a=200 mm of the low-frequency sound insulation unit, and good ventilation performance is shown while good low-frequency sound insulation performance is ensured, so that the double-layer low-frequency ventilation type sound insulation barrier can be used for isolating building space and equipment noise under ventilation conditions, and noise pollution is reduced.
Fig. 12 is a schematic diagram of the double-layer low-frequency ventilation type sound insulation barrier of the low-frequency sound insulation unit based on different parameters d. And two low-frequency sound insulation units are arranged at intervals along the y direction to form a composite unit II, a plurality of composite units II are arranged at intervals along the x direction to form a double-layer low-frequency ventilation type sound insulation barrier II, the parameters d of the first resonant cavity 1 and the second resonant cavity 2 of the two low-frequency sound insulation units are not completely identical, and other parameters are identical. The length of the low-frequency sound insulation unit is 2a=200mm, the width t of the first and second winding channels 41 and 42 is 6mm, the width t 1 of the cavity entrance 44 is 6mm, the thickness e of the winding channel wall 53 is 2mm, and the length a=100deg.M of the outer side wall at the channel entrance 43 of the first and second winding channels 41 and 42. And the center-to-center distance between two low-frequency sound insulation units in the composite unit II is H 2 =150 mm, and the center-to-center distance L 2 =400 mm between adjacent composite units II. The lengths d of the drawer-type frames 6 drawn out by the second frames 62 in the drawer-type frames 6 of the four resonant cavities in the composite unit II are not completely the same, the adjusting range is more than or equal to 0 and less than or equal to 50mm, and other parameters are the same.
Numerical simulation is carried out through the Comsol software, a plurality of low-frequency sound insulation unit models with the length of 2 a=200 mm, the widths t of the first winding channel 41 and the second winding channel 42 are 6mm, the width t 1 of the cavity inlet 44 is 6mm, the thickness e of the winding channel wall 53 is 2mm, the length a=100 mm of the outer side wall at the channel inlet 43 of the first winding channel 41 and the second winding channel 42, the material density is 1180kg/m 3, the longitudinal wave speed 2720m/s and the transverse wave speed 1460m/s are constructed, and the simulation environment parameters are the density of air 1.21kg/m 3 and the sound velocity 343m/s. And arranging the constructed low-frequency sound insulation units into a double-layer low-frequency ventilation type sound insulation barrier II according to the arrangement mode. The frequency of the sound wave signal is changed within the range of 110-180Hz, the length d positive direction of the drawer-type frame 6 drawn by the second frame 62 in the drawer-type frame 6 of the four resonant cavities in the composite unit II is controlled to be d 1＝0mm、d2＝10mm、d3＝20mm、d4 =30 mm along the reverse N shape, the sound energy transmittance under different frequencies is calculated in a simulation mode, and the change relation diagram of the sound energy transmittance and the frequency of the double-layer low-frequency ventilation type sound insulation barrier II simulated in the figure 13 is obtained. It can be seen that, in the 136-158Hz frequency band range (black shadow area), the acoustic energy transmittance of the second double-layer low-frequency ventilation type sound insulation barrier is lower than-5 dB, compared with the scheme in fig. 10 of this embodiment, the working frequency band is changed, the working bandwidth is increased, and the flexible and adjustable low-frequency ventilation and sound insulation performance of a wider frequency band is shown.
Example IV
Fig. 14 is a schematic diagram of the complex double-layer broadband ventilation type sound insulation barrier, two low-frequency sound insulation units are closely arranged along the x direction to form a unit group, two unit groups are arranged at intervals along the y direction to form a composite unit III, and a plurality of composite units III are arranged at intervals along the x direction to form the complex double-layer broadband ventilation type sound insulation barrier. The lengths d of the drawer-type frames 6 drawn out by the second frames 62 in the eight resonant cavities in the composite unit III are not completely the same, the adjusting range is more than or equal to 0 and less than or equal to 50mm, and other parameters are the same. The length of the low-frequency sound insulation unit is 2a=200mm, the width t of the first and second winding channels 41 and 42 is 6mm, the width t 1 of the cavity entrance 44 is 6mm, the thickness e of the winding channel wall 53 is 2mm, and the length a=100deg.M of the outer side wall at the channel entrance 43 of the first and second winding channels 41 and 42. And the center-to-center distance between two unit groups in the compound unit III is H 3 =150 mm, and the center-to-center distance L 3 =600 mm between adjacent compound units III.
Numerical simulation is carried out through the Comsol software, a plurality of low-frequency sound insulation unit models with the length of 2 a=200 mm, the widths t of the first winding channel 41 and the second winding channel 42 are 6mm, the width t 1 of the cavity inlet 44 is 6mm, the thickness e of the winding channel wall 53 is 2mm, the length a=100 mm of the outer side wall at the channel inlet 43 of the first winding channel 41 and the second winding channel 42, the material density is 1180kg/m 3, the longitudinal wave speed 2720m/s and the transverse wave speed 1460m/s are constructed, and the simulation environment parameters are the density of air 1.21kg/m 3 and the sound velocity 343m/s. And arranging the constructed low-frequency sound insulation units into a complex double-layer broadband ventilation type sound insulation barrier according to the arrangement mode. The frequency of the sound wave signal is changed within the range of 110-180Hz, the second frame 62 in the drawer-type frame 6 of eight resonant cavities in the composite unit III is controlled to be pulled out of the length d of the drawer-type frame 6, the sound energy transmittance under different frequencies is calculated through simulation along the N-shaped direction along d1＝5mm、d2＝10mm、d3＝15mm、d4＝20mm、d5＝25mm、d6＝30mm、d7＝35mm、d8＝40mm. in sequence, and the relation diagram of the sound energy transmittance and the frequency change of the complex double-layer broadband ventilation type sound insulation barrier in the numerical simulation in FIG. 15 is obtained. It can be seen that, in the 122-166Hz frequency band range (black shaded area), the acoustic energy transmittance of the complex double-layer broadband ventilation type sound insulation barrier is lower than-5 dB, the relative bandwidth is F foc＝2(fH-fL)/(fH+fL) =2× (166-122)/(166+122) =31%, wherein F H and F L are the upper limit frequency and the lower limit frequency of the working frequency band respectively, the relative bandwidth reaches 31%, and in addition, the lowest acoustic transmittance is-16 dB, so that the broadband adjustable low-frequency sound insulation effect is realized. Similarly, a certain distance exists between the adjacent composite units III, so that good ventilation performance is shown while good low-frequency sound insulation performance is ensured, and the method can be used for isolating building space from equipment noise under the ventilation condition.
The examples are preferred embodiments of the present invention, but the present invention is not limited to the above-described embodiments, and any obvious modifications, substitutions or variations that can be made by one skilled in the art without departing from the spirit of the present invention are within the scope of the present invention.
Claims (10)
1. The utility model provides a low frequency sound insulation unit of frequency band adjustable which characterized in that: the device comprises a first resonant cavity (1) and a second resonant cavity (2) which are arranged next to each other in the x direction and have the same structure, two cover plates (7) positioned at two ends of the first resonant cavity (1) and the second resonant cavity (2) in the z direction, wherein the first resonant cavity (1) and the second resonant cavity (2) comprise a rectangular cavity (3) positioned in the middle, a first curling channel (41) and a second curling channel (42) which are respectively positioned at the left side and the right side of the rectangular cavity (3) and are symmetrically arranged, the rectangular cavity (3) is formed by nesting a first U-shaped frame (61) and a second U-shaped frame (62) which are opposite in opening, and a cavity inlet (44) is formed in one side wall of the first frame (61) opposite to the opening; the first and second crimping passages (41, 42) communicate at the cavity inlet (44) and are fixed relative to the position of the first frame (61);
The first (41) and second (42) winding channels each have a plurality of serpentine bends, and the channel inlets (43) of the first (41) and second (42) winding channels are in the y-direction; the directions of the sound channel inlets (43) and the cavity inlets (44) on the first resonant cavity (1) and the second resonant cavity (2) are opposite.
2. The low frequency sound insulation unit according to claim 1, wherein: the length of the first resonant cavity (1) and the second resonant cavity (2) is a, the thickness of the winding channel walls (5) of the first winding channel (41) and the second winding channel (42) is e=0.02 a, the width of the first winding channel (41) and the second winding channel (42) is t=0.06 a, the width t 1 of the cavity inlet (44) is t=0.06 a, the range of the length d of the second frame (62) drawn out of the drawer type frame (6) in the drawer type frame (6) is 0.ltoreq.d.ltoreq.50 mm, and the length of the outer side wall at the sound channel inlet (43) of the first winding channel (41) and the second winding channel (42) is a; preferably, the a=100 mm.
3. The low frequency sound insulation unit according to claim 1, wherein: the low-frequency sound insulation unit is made of organic glass or resin; the number of serpentine bends of the first and second winding channels (41, 42) is not less than two.
4. Use of a low frequency sound insulation unit according to any of claims 1-3, characterized in that: the device is used for isolating ventilation type low-frequency noise in building space or equipment, and the working frequency band is 120-170Hz.
5. A single-layer low-frequency ventilated sound barrier based on a low-frequency sound-insulation unit according to any one of claims 1 to 3, characterized in that: the low-frequency sound insulation units are arranged at intervals along the x direction, the parameters of the low-frequency sound insulation units are the same, the interval distance between the adjacent low-frequency sound insulation units is L, and the range of the length d of the drawer-type frame (6) drawn out by the second frame (62) in the drawer-type frame (6) is more than or equal to 0 and less than or equal to 50mm.
6. The single layer low frequency ventilated sound barrier of claim 5, wherein: the center-to-center distance between two adjacent low-frequency sound insulation units is L=400 mm.
7. A double-layered low-frequency ventilated sound barrier based on a low-frequency sound insulation unit according to any one of claims 1 to 3, characterized in that: the two low-frequency sound insulation units are arranged at intervals along the y direction to form a composite unit, and a plurality of composite units are arranged at intervals along the x direction to form a double-layer low-frequency ventilation type sound insulation barrier; the distance H 1 between the centers of two low-frequency sound insulation units in the composite unit is 150mm, and the distance L 1 between the centers of two adjacent composite units is 400mm; the length d of the drawer-type frame (6) drawn out by the second frames (62) of the first resonant cavity (1) and the second resonant cavity (2) in the composite unit is more than or equal to 0 and less than or equal to 50mm.
8. The double-deck low frequency ventilation sound barrier of claim 7, wherein: the lengths d of the drawer-type frames (6) drawn out by the second frames (62) in the four resonant cavities in the composite unit are not completely the same, and other parameters are the same.
9. A complex double-layer broadband ventilation type sound insulation barrier based on a low frequency sound insulation unit according to any one of claims 1-3, characterized in that: the two low-frequency sound insulation units are arranged next to each other along the x direction to form a unit group, the two unit groups are arranged at intervals along the y direction to form a composite unit III, a plurality of composite units III are arranged at intervals along the x direction to form a complex double-layer broadband ventilation type sound insulation barrier, the center-to-center distance of the two unit groups in the composite unit III is H 3 =150 mm, the center-to-center distance L 3 =600 mm of the adjacent composite units III, and the length d range of the drawer type frame (6) drawn out by the second frames (62) of the first resonant cavity (1) and the second resonant cavity (2) in the composite unit III is more than or equal to 0 and less than or equal to 50mm.
10. The complex double-layer broadband ventilation type sound insulation barrier according to claim 9, wherein: the lengths d of the drawer-type frames (6) drawn out by the second frames (62) in the eight resonant cavities in the composite unit III are not completely the same, and other parameters are the same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410421933.1A CN118116356A (en) | 2024-04-09 | 2024-04-09 | Low-frequency sound insulation unit with adjustable frequency band and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410421933.1A CN118116356A (en) | 2024-04-09 | 2024-04-09 | Low-frequency sound insulation unit with adjustable frequency band and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118116356A true CN118116356A (en) | 2024-05-31 |
Family
ID=91208758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410421933.1A Pending CN118116356A (en) | 2024-04-09 | 2024-04-09 | Low-frequency sound insulation unit with adjustable frequency band and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118116356A (en) |
-
2024
- 2024-04-09 CN CN202410421933.1A patent/CN118116356A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kumar et al. | Ventilated acoustic metamaterial window panels for simultaneous noise shielding and air circulation | |
| Zhu et al. | Nonlocal acoustic metasurface for ultrabroadband sound absorption | |
| JP6438025B2 (en) | Sound waveguide for use in acoustic structures | |
| CN109147750A (en) | A kind of low frequency coupling sound absorption structure | |
| CN108374805B (en) | A ventilation formula acoustics metamaterial sound insulation bucket for transformer fan falls and makes an uproar | |
| Xu et al. | Topology-optimized omnidirectional broadband acoustic ventilation barrier | |
| CN108682411B (en) | Broadband low-frequency acoustic silencer | |
| CN212614404U (en) | Broadband ventilation sound insulation window unit structure and broadband sound barrier | |
| CN109036362B (en) | Broadband low-frequency acoustic absorber | |
| CN113096626A (en) | Silent box | |
| CN111561252A (en) | Broadband ventilation sound insulation window unit structure and application thereof | |
| Gao et al. | Broadband ventilated sound insulation in a highly sparse acoustic meta-insulator array | |
| CN115731912A (en) | Micro-perforated plate sound absorption structure and design method | |
| Baek et al. | Design of flat broadband sound insulation metamaterials by combining Helmholtz resonator and fractal structure | |
| CN109119059B (en) | Double-negative-acoustic metamaterial structure based on Helmholtz resonator coupling | |
| CN109185233A (en) | The fractal structure acoustic metamaterial device of for transformer noise reduction | |
| CN118116356A (en) | Low-frequency sound insulation unit with adjustable frequency band and application thereof | |
| CN113654232A (en) | Noise elimination structure suitable for heating and ventilating system air port | |
| CN112951191B (en) | Low-frequency broadband sound absorption composite structure and preparation method thereof | |
| Su et al. | Customizable acoustic metamaterial barrier with intelligent sound insulation | |
| CN212587216U (en) | Multilayer micro-perforated plate sound absorption structure | |
| CN220203039U (en) | Resonant cavity sound absorption structure and low-frequency sound insulation heat preservation wall | |
| CN112854990A (en) | Broadband ventilation sound insulation window unit structure and application thereof | |
| CN113123261A (en) | Bionic sound absorption structure based on conch cavity structure and sound absorption unit plate thereof | |
| CN112628517A (en) | Pipeline silencer, device and manufacturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |