CN111696508B - Coarse inner intubation type Helmholtz resonance sound absorption structure - Google Patents
Coarse inner intubation type Helmholtz resonance sound absorption structure Download PDFInfo
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- CN111696508B CN111696508B CN202010486472.8A CN202010486472A CN111696508B CN 111696508 B CN111696508 B CN 111696508B CN 202010486472 A CN202010486472 A CN 202010486472A CN 111696508 B CN111696508 B CN 111696508B
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
Abstract
The invention discloses a rough inner insertion tube type Helmholtz resonance sound absorption structure. The invention has excellent low-frequency sound absorption performance, good bearing performance and light weight performance. Have more adjustable structural parameters in the aspect of the design, can carry out corresponding regulation according to the operating condition demand, simple structure easily makes.
Description
Technical Field
The invention belongs to the technical field of air sound absorption, and particularly relates to a rough inner insertion tube type Helmholtz resonance sound absorption structure.
Background
Helmholtz resonance chamber is a typical resonance sound absorbing structure, in practical application, utilizes microperforated panel and back of the body chamber structure Helmholtz resonance structure usually, absorbs the sound wave in the air through Helmholtz resonance to realize the damping in movie theatre, meeting room, the car cabin and fall the design of making an uproar.
However, for the micro-perforated plate structure, if the micro-perforated plate structure is to achieve efficient absorption of sound waves in lower frequency bands, the thickness of the micro-perforated plate needs to be increased and the aperture of the micro-perforations needs to be reduced, which causes the mass and volume of the structure to be increased, and is not favorable for light weight design and manufacturing. In addition, the hole type of the micro-perforation is generally a regular cylindrical hole, the internal damping of the micro-perforation is small, and the micro-perforation is not beneficial to increasing the sound absorption bandwidth and improving the low-frequency sound absorption performance.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a rough inner insertion tube type helmholtz resonance sound absorption structure, which solves the problems of narrow bandwidth, poor low frequency sound absorption performance, difficult processing and manufacturing, large size and poor light weight performance of the conventional air sound absorption structure.
The invention adopts the following technical scheme:
the utility model provides a roughly interior intubate formula helmholtz resonance sound absorption structure, includes the cavity, and the one end center of cavity is opened porosely, is provided with roughly interior intubate in the downthehole, roughly interior intubate and cavity welding or the mode of gluing connect and constitute roughly interior intubate formula helmholtz resonance sound absorption structure.
Specifically, the cavity is cylindrical, rectangular, hexagonal or irregular.
Furthermore, the diameter of the cavity is 20-30 mm.
Further, the height of the cavity is 30-50 mm.
Specifically, the axial roughness of the inner wall of the rough inner interpolation tube satisfies the function gamma relationship as follows:
Г＝d×[0.5-δcos(βx)]
wherein d is the average diameter of the rough inner insert tube, δ is the relative roughness of the rough inner insert tube, β is the space wave number of the rough inner insert tube, and x is the coordinate along the length direction of the rough inner insert tube.
Specifically, the length of the rough inner insert tube is 25-40 mm.
Specifically, the average diameter of the rough inner insert tube is 3-5 mm.
Specifically, the relative roughness of the rough inner insert tube is 0.15 to 0.25.
Specifically, the spatial wave number of the rough inner insert tube is 0.96 pi-2 pi.
Specifically, the cavity and the rough inner insert tube are both made of structural steel, resin, wood or composite materials.
Compared with the prior art, the invention has at least the following beneficial effects:
according to the rough inner insert pipe type Helmholtz resonance sound absorption structure, the rough inner insert pipe is connected with the opening on the cavity through welding or gluing, the inside of the cavity is communicated with the outside through the rough inner insert pipe, air flows into the inside of the cavity through the rough inner insert pipe to form a Helmholtz resonant cavity, axial roughness is introduced to the inner wall of the inner insert pipe, the acoustic impedance characteristic of the structure is improved, the low-frequency sound absorption performance of the structure is improved, and the sound absorption bandwidth of the structure is widened; the cavity structure reduces the structure weight on the premise of realizing good low-frequency sound absorption performance, ensures the structure bearing performance, and solves the problems that the traditional micro-perforated plate sound absorption structure has narrow bandwidth, poor low-frequency sound absorption performance, difficult processing and manufacturing, large size and poor light weight performance.
Furthermore, the diameter of the cavity is 20-30 mm, the cavity is used as a Helmholtz resonant cavity to play a role in sound capacity, and the peak sound absorption frequency of the structure can be controlled by adjusting the diameter of the cavity.
Furthermore, the height of the cavity is 30-50 mm, the height of the cavity determines the size of the resonant cavity, and the sound absorption frequency band of the structure can be adjusted by changing the height of the cavity.
Furthermore, the axial roughness meeting the function Gamma is introduced into the inner wall of the inner inserting tube, and the acoustic damping device has the advantages that on one hand, the acoustic resistance and the acoustic mass of the inner inserting tube are increased through the roughness, the damping characteristic of the structure is improved, the resonance sound absorption frequency of the structure is reduced, and the structure can realize better sound absorption performance at a lower frequency band; on the other hand, the adjustable parameters of the structure are increased, so that the structure has more excellent performance adjustability.
Furthermore, the average diameter of the rough inner inserting pipe is 3-5 mm, the diameter of the rough inner inserting pipe determines the diameter of an air column in the pipe, and the Helmholtz resonance characteristic of the structure can be changed by adjusting the diameter of the rough inner inserting pipe, so that the sound absorption performance of the structure is adjusted.
Furthermore, the length of the rough inner insert tube is 25-40 mm, and the length of the rough inner insert tube determines the height of the air column in the perforation and controls the resonance sound absorption characteristic of the structure.
Furthermore, the relative roughness of the rough inner insert tube is 0.15-0.25, the relative roughness of the rough inner insert tube determines the diameter change amplitude of the air column in the tube, and the acoustic impedance of the structure can be regulated and controlled by regulating the relative roughness of the rough inner insert tube, so that the sound absorption performance of the structure can be regulated and controlled.
Furthermore, the spatial wave number of the rough inner insert tube is 0.96 pi-2 pi, the spatial wave number of the rough inner insert tube determines the diameter change condition of an air column in the tube, and the acoustic impedance of the structure can be regulated and controlled by regulating the spatial wave number of the rough inner insert tube, so that the sound absorption performance of the structure can be regulated and controlled.
Furthermore, the cavity and the rough inner inserting pipe are made of hard materials such as structural steel, resin, wood or composite materials, and the application of the structural steel enables the structure to have good bearing performance
In conclusion, the sound-absorbing material has excellent low-frequency sound absorption performance, good bearing performance and light weight. Have more adjustable structural parameters in the aspect of the design, can carry out corresponding regulation according to the operating condition demand, simple structure easily makes.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a schematic structural view of the present invention, wherein (a) is a perspective view, (b) is a sectional view, and (c) is a sectional view of a roughened inner cannula;
FIG. 2 is a graphical representation of the sound absorption coefficient within 100-400 Hz for three embodiments of the present invention.
Wherein: 1. a cavity; 2. and (4) roughening the inner intubation.
Detailed Description
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "one side", "one end", "one side", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Various structural schematics according to the disclosed embodiments of the invention are shown in the drawings. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.
The invention provides a rough inner insertion tube type Helmholtz resonance sound absorption structure, wherein a cavity and the rough inner insertion tube are connected in a welding or gluing mode to form a Helmholtz resonance cavity, axial roughness is introduced into the inner wall of the inner insertion tube, the acoustic impedance characteristic of the structure is improved, the low-frequency sound absorption performance of the structure is improved, and the sound absorption bandwidth of the structure is widened. The cavity structure has alleviateed structural weight under the prerequisite that realizes good low frequency sound absorptivity, has guaranteed structure bearing capacity, has solved traditional microperforated panel sound absorbing structure and has narrow, the low frequency sound absorptivity of ubiquitous bandwidth is not good, manufacturing difficulty, size is great, the light weight not good problem of performance.
Referring to fig. 1, the rough inner intubation type helmholtz resonance sound absorption structure of the present invention includes a cavity 1 and a rough inner intubation 2, wherein the rough inner intubation 2 is sleeved in the cavity 1 and connected by welding or glue bonding to form the rough inner intubation type helmholtz resonance sound absorption structure.
The cavity 1 is made of hard materials such as structural steel, resin, wood or composite materials, the upper surface of the cavity is provided with a small hole, the rough inner insert tube 2 is arranged in the small hole, the lower surface of the cavity 1 is fixed on the surface of a wall body needing acoustic treatment, the diameter of the cavity 1 is 20-30 mm, the height of the cavity 1 is 30-50 mm, and the shape of the cavity is cylindrical, cuboid, hexagonal prism or irregular.
The rough inner insert tube 2 is made of hard materials such as structural steel, resin, wood or composite materials and the like, is connected with an opening on the cavity through welding or cementing, and the axial roughness of the inner wall of the rough inner insert tube 2 is characterized by a function gamma, and specifically comprises the following steps:
Г＝d×[0.5-δcos(βx)]
wherein d is the average diameter of the rough inner insert tube, δ is the relative roughness of the rough inner insert tube, β is the space wave number of the rough inner insert tube, and x is the coordinate along the length direction of the rough inner insert tube.
The rough inner insert tube 2 has a length of 25-40 mm, an average diameter of 3-5 mm, a relative roughness of 0.15-0.25, and a spatial wave number of 0.96-2 pi.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention is composed of a cavity and a rough inner insert tube, the sound absorption performance of the invention is mainly determined by resonance cavity parameters, and the sound absorption performance of the invention specifically comprises the cavity diameter, the cavity height, the rough inner insert tube diameter, the rough inner insert tube relative roughness, the rough inner insert tube space wave number and the rough inner insert tube length. The bearing and light weight performance is mainly determined by the size of the cavity, including the diameter and height of the cavity. Because the structural parameters are adjustable parameters, the corresponding sound absorption, bearing and lightweight performance requirements can be realized through adjustment. The technical solution of the present invention is exemplarily illustrated by the following specific examples.
Materials for examples:
structural steel: it is characterized by a density of 7850kg/m 3 Young's modulus 200GPa, poisson's ratio 0.2.
Air: it is characterized by a density of 1.29kg/m 3 Sound velocity 343m/s, dynamic viscosity coefficient 1.81X 10 -5 Pa·s。
Structural dimensions and material selection of comparative examples:
comparative example
As a comparative example, a roughness-free inner-tube type Helmholtz resonance sound absorbing structure in which the diameter of the cavity was 20mm, the height of the cavity was 30mm, the diameter of the inner tube was 3mm, and the length of the inner tube was 25mm was selected.
Structural dimensions and material selection of the examples:
example 1
The diameter of the cavity is 20mm, the height of the cavity is 30mm, the diameter of the rough inner insert is 3mm, the relative roughness of the rough inner insert is 0.15, the spatial wave number of the rough inner insert is 0.96 pi, and the length of the rough inner insert is 25mm.
Example 2
The diameter of a cavity is 25mm, the height of the cavity is 40mm, the diameter of the rough inner insert is 4mm, the relative roughness of the rough inner insert is 0.2, the spatial wave number of the rough inner insert is 1.6 pi, and the length of the rough inner insert is 30mm.
Example 3
The diameter of a cavity is 30mm, the height of the cavity is 50mm, the diameter of the rough inner insert is 5mm, the relative roughness of the rough inner insert is 0.25, the space wave number of the rough inner insert is 2 pi, and the length of the rough inner insert is 40mm.
Referring to fig. 2, the helmholtz resonance phenomenon at low frequency can achieve high-efficiency sound absorption in a certain frequency range. By introducing axial roughness into the inner wall of the inner insertion tube, the acoustic impedance characteristic of the structure is improved, and the acoustic resistance and the acoustic quality of the structure are enhanced, so that the low-frequency perfect sound absorption is realized.
Referring to fig. 2, the comparative example reached a peak sound absorption value at 315Hz, which was 0.94, and perfect sound absorption was not achieved.
Example 1 has the same structural parameters as the comparative example, except that the inner wall of the inner insert tube of example 1 has an axial roughness that achieves perfect sound absorption at 292Hz with a peak sound absorption of 0.99. Compared with the comparative example, after the inner cannula introduces the axial roughness, the sound absorption peak value of the invention is shifted to 23Hz (7%) and the sound absorption peak value is increased by 0.05 (5%). The sound absorption properties of the structure are greatly improved compared to the comparative examples. At the moment, the thickness of the structure is only 30mm and is 1/39 of the corresponding perfect sound absorption wavelength, so that the structure is a deep sub-wavelength scale low-frequency perfect sound absorption metamaterial;
example 2 after further optimization of the structural parameters, perfect sound absorption was achieved at 224Hz with a peak sound absorption value of 0.99. Compared with the comparative example, the peak sound absorption of example 2 is shifted by 91Hz (29%) to a low frequency, and the peak sound absorption is increased by 0.05 (5%). The sound absorption properties of the structure are greatly improved compared to the comparative examples. At the moment, the thickness of the structure is only 40mm and is 1/38 of the corresponding perfect sound absorption wavelength, so that the structure is a deep sub-wavelength scale low-frequency perfect sound absorption metamaterial;
example 3 after further optimization of the structural parameters, perfect sound absorption was achieved at 165Hz with a peak sound absorption value of 0.99. In comparison with the comparative example, the peak sound absorption of example 3 was shifted by 150Hz (48%) to a low frequency, and the peak sound absorption was increased in size by 0.05 (5%). The sound absorption properties of the structure are greatly improved compared to the comparative examples. At the moment, the thickness of the structure is only 50mm and is 1/42 of the corresponding perfect sound absorption wavelength, so that the structure is a deep sub-wavelength scale low-frequency perfect sound absorption metamaterial;
the sound absorption coefficient curve shows that the invention can realize excellent low-frequency sound absorption performance in a certain frequency range, and the adjustment of the acoustic performance can be realized through the design of different structural parameters.
In summary, the invention achieves the following technical effects:
1. has excellent low-frequency sound absorption performance. The sound absorption coefficient of the test piece of the invention at a certain frequency of 100-400 Hz can reach more than 0.99, and perfect sound absorption is realized. Compared with the traditional structure, the sound absorption coefficient of the sound absorption structure is shifted to low frequency by 7% -48%, and the peak value of the sound absorption coefficient is improved by 5%. And the structure thickness is only 1/42-1/38 of the corresponding perfect sound absorption wavelength, and the super-material is a deep sub-wavelength scale low-frequency perfect sound absorption super-material.
2. Has good bearing performance and light weight performance. The cavity is made of hard materials such as structural steel, and the structure has good pressure resistance and is a multifunctional structure with bearing and light weight.
3. With more adjustable parameters and variables. The diameter of the cavity, the height of the cavity, the diameter of the rough inner insert tube, the relative roughness of the rough inner insert tube, the spatial wave number of the rough inner insert tube and the length of the rough inner insert tube are all adjustable parameters, and can be selected and adjusted reasonably according to specific use scenes, such as the requirement on bearing performance or the requirement on acoustic performance.
4. Simple structure and easy manufacture.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (4)
1. The rough inner-inserting-tube type Helmholtz resonance sound absorption structure is characterized by comprising a cavity (1), wherein a hole is formed in the center of one end of the cavity (1), a rough inner inserting tube (2) is arranged in the hole, the rough inner inserting tube (2) and the cavity (1) are connected in a welding or gluing mode to form the rough inner-inserting-tube type Helmholtz resonance sound absorption structure, the diameter of the cavity (1) is 20-30mm, the height of the cavity (1) is 30-50mm, the length of the rough inner inserting tube (2) is 25-40mm, the average diameter of the rough inner inserting tube (2) is 3-5mm, the relative roughness of the rough inner inserting tube (2) is 0.15-0.25, and the space wave number of the rough inner inserting tube (2) is 0.96-2 pi.
2. A rough insert tube type helmholtz resonance sound absorbing structure according to claim 1, wherein the shape of the cavity (1) is a cylinder type, a rectangular parallelepiped type, a hexagonal prism type or an irregular type.
3. A rough inner-intubation helmholtz resonance sound absorbing structure according to claim 1, wherein the axial roughness of the inner wall of the rough inner-intubation (2) satisfies a function
The relationship is as follows:
wherein the content of the first and second substances,
is the average diameter of the roughened inner catheter>
For the relative roughness of the roughened inner tube, <' > or>
The spatial wavenumber of the rough interpolator, and x is the coordinate along the length of the rough interpolator.
4. A rough inner-tube helmholtz resonance sound absorbing structure according to claim 1, wherein the cavity (1) and the rough inner-tube (2) are made of structural steel, resin, wood or composite material.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113362798A (en) * | 2021-05-10 | 2021-09-07 | 西安交通大学 | Variable tubular inner insertion tube type honeycomb layer core sandwich plate sound absorption structure |
| CN113362796A (en) * | 2021-05-10 | 2021-09-07 | 西安交通大学 | Two-way rough inner insertion tube type Helmholtz resonance sound absorption structure |
| CN113362793A (en) * | 2021-05-10 | 2021-09-07 | 西安交通大学 | Porous sound absorbing structure with micro-channels arranged in bidirectional rough parallel manner |
| CN113362795A (en) * | 2021-05-10 | 2021-09-07 | 西安交通大学 | Porous sound absorbing structure of petal-shaped channel |
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