阅读说明：本技术 一种内置空气层的四方蜂窝复合水下吸声结构 (Square honeycomb composite underwater sound absorption structure with built-in air layer ) 是由 辛锋先 卢天健 于晨磊 段明宇 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种内置空气层的四方蜂窝复合水下吸声结构,包括四方蜂窝结构,四方蜂窝结构设置在底板上,四方蜂窝结构的上表面设置有覆盖层,四方蜂窝结构内部的每个元胞内填充有粘弹性材料,粘弹性材料与底板之间设置有空气层。本发明可以很大程度提高粘弹性材料的吸声性能,在设计方面具有更多的可调参数,包括结构参数以及材料参数,可根据实际工况需求进行相应调节,结构简单,易于制造。(The invention discloses a square honeycomb composite underwater sound absorption structure with a built-in air layer, which comprises a square honeycomb structure, wherein the square honeycomb structure is arranged on a bottom plate, a covering layer is arranged on the upper surface of the square honeycomb structure, each cell in the square honeycomb structure is filled with a viscoelastic material, and the air layer is arranged between the viscoelastic material and the bottom plate. The invention can improve the sound absorption performance of the viscoelastic material to a great extent, has more adjustable parameters in the design aspect, including structural parameters and material parameters, can be correspondingly adjusted according to the requirements of actual working conditions, and has simple structure and easy manufacture.)

1. The utility model provides a compound underwater sound absorption structure of square honeycomb of built-in air bed which characterized in that, includes square honeycomb structure (2), and square honeycomb structure (2) set up on the bottom plate, and the upper surface of square honeycomb structure (2) is provided with overburden (1), and every cellular intussuseption of square honeycomb structure (2) inside is filled with viscoelastic material, is provided with air bed (3) between viscoelastic material and the bottom plate.

2. A square honeycomb composite underwater sound absorbing structure with an air layer built in according to claim 1, characterized in that the square honeycomb structure (2) comprises a plurality of partitions which are arranged on the bottom plate at intervals and distributed along the transverse direction and the longitudinal direction of the bottom plate, and two adjacent partitions constitute a cell.

3. The square honeycomb composite underwater sound absorption structure with the built-in air layer as claimed in claim 2, wherein the thickness of the partition plate is 0.5 to 3mm, and the height of the partition plate is 21 to 51 mm.

4. A tetragonal honeycomb composite underwater sound absorbing structure with an embedded air layer as claimed in claim 2 or 3, wherein the tetragonal honeycomb structure (2) is made of a metal material or a carbon fiber/glass fiber composite material.

5. The square honeycomb composite underwater sound absorption structure with the built-in air layer as claimed in claim 2, wherein the width of the unit cell is 10-30 mm.

6. The square honeycomb composite underwater sound absorbing structure with an air layer built in according to claim 1, wherein the thickness h of the viscoelastic material filled in each cell₂20 to 50 mm.

7. A tetragonal honeycomb composite underwater sound absorbing structure with an air layer built in according to claim 1, wherein the thickness h of the air layer (3)₁Is 1-10 mm.

8. A tetragonal honeycomb composite underwater sound absorbing structure with an air layer built in according to claim 1, wherein the thickness h of the cover layer (1)₃Is 1-10 mm.

9. The square honeycomb composite underwater sound absorbing structure with an air layer built in according to claim 8, wherein the cover layer (1) is made of viscoelastic material.

10. The method of claim 1 or 9The square honeycomb composite underwater sound absorption structure with the built-in air layer is characterized in that the density of the viscoelastic material is 800-1400 kg/m³The transverse wave sound velocity of the viscoelastic material is 500-2000 m/s, and the transverse wave loss factor of the viscoelastic material is 0.01-0.3; the longitudinal wave sound velocity of the viscoelastic material is 30-300 m/s, and the longitudinal wave loss factor of the viscoelastic material is larger than 0.5.

Technical Field

The invention belongs to the technical field of underwater sound absorption composite structures, and particularly relates to a square honeycomb composite underwater sound absorption structure with an air layer inside.

Background

At present, sound waves are the only effective medium for long-distance underwater information transmission, so that the sound waves are widely applied to underwater reconnaissance. As a typical anti-reconnaissance method, the sound-deadening layer reduces the intensity of the reflected sound wave by absorbing a portion of the incident sound energy. Viscoelastic materials, such as rubber and polyurethane, are often used as the basis for the sound absorbing layer because of their acoustic impedance matching with water. Under the excitation of incident sound waves, polymer chains inside the viscoelastic material begin to vibrate, and friction inside molecules consumes part of the sound energy. However, the absorption of low frequency sound remains a great challenge due to the inherently poor dissipation of viscoelastic materials in the low frequency domain. In addition, the wavelength of the low-frequency sound wave in water is longer, and the only method for effectively attenuating the low-frequency sound absorption by using the original uniform viscoelastic material is to increase the thickness of the material, which is mutually contradictory to the actual situation.

In practical application, most of the sound absorption layers are of a cavity resonance structure type, namely cavities with various shapes are embedded inside. As the frequency of the incident acoustic wave approaches the natural frequency of the cavity, the vibration of the polymer chains is exacerbated and the acoustic energy is severely dissipated by intramolecular friction. However, the sound absorption frequency band of the resonance noise elimination structure is narrow, and the cavity is sensitive to water pressure, so that the actual requirements of deep sea conditions cannot be met. Challenges still exist in the design of underwater broadband sound absorbing structures and water pressure resistant sound absorbing structures.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a square honeycomb composite underwater sound absorption structure with a built-in air layer aiming at the defects in the prior art, improve the underwater sound absorption performance of sound absorption rubber through reasonable design of the structure, and solve the problem of poor broadband sound absorption performance of a viscoelastic material.

The invention adopts the following technical scheme:

the utility model provides a compound underwater sound absorption structure of square honeycomb of built-in air bed, includes square honeycomb, and square honeycomb sets up on the bottom plate, and square honeycomb's upper surface is provided with the overburden, and the inside every cell of square honeycomb is filled with viscoelastic material, is provided with the air bed between viscoelastic material and the bottom plate.

Specifically, the square honeycomb structure comprises a plurality of partition plates, the partition plates are arranged on a bottom plate at intervals and distributed along the transverse direction and the longitudinal direction of the bottom plate, and two adjacent partition plates form a cell.

Furthermore, the thickness of the partition plate is 0.5-3 mm, and the height of the partition plate is 21-51 mm.

Furthermore, the square honeycomb structure is made of a metal material or a carbon fiber/glass fiber composite material.

Furthermore, the width of the unit cell is 10-30 mm.

Specifically, the thickness h of the viscoelastic material filled in each cell₂20 to 50 mm.

In particular, the thickness h of the air layer₁Is 1-10 mm.

In particular, the thickness h of the cover layer₃Is 1-10 mm.

Further, the cover layer is made of a viscoelastic material.

Furthermore, the density of the viscoelastic material is 800-1400 kg/m³The transverse wave sound velocity of the viscoelastic material is 500-2000 m/s, and the transverse wave loss factor of the viscoelastic material is 0.01-0.3; the longitudinal wave sound velocity of the viscoelastic material is 30-300 m/s, and the longitudinal wave loss factor of the viscoelastic material is larger than 0.5.

Compared with the prior art, the invention has at least the following beneficial effects:

the invention relates to a square honeycomb composite underwater sound absorption structure with a built-in air layer, which is characterized in that a square honeycomb structure is connected with a bottom plate, and cells of the square honeycomb structure are filled with viscoelastic underwater sound absorption materials; because the square honeycomb structure is connected with the bottom plate and has higher rigidity, the wall surface of the square honeycomb structure cannot vibrate due to the disturbance of sound waves; the viscoelastic material vibrates under the excitation of sound waves, because of the existence of the square honeycomb structure, the vibration of the material close to the honeycomb wall surface of the square honeycomb structure is restrained, and the vibration of the material far away from the honeycomb wall surface of the square honeycomb structure is relatively violent, so that a strong shearing action is generated in the viscoelastic material; the shear loss of the viscoelastic material is far greater than the compression loss, so that the sound wave loss capability of the viscoelastic material can be greatly improved; on the other hand, an air layer is arranged between the viscoelastic material and the bottom plate, and the air layer releases bottom restraint, so that the vibration of the viscoelastic material is enhanced, and the sound wave loss capacity of the viscoelastic material is further improved; on the other hand, the square honeycomb structure is connected with the bottom plate, and pressure is transmitted to the bottom plate through the square honeycomb structure, so that the structure has certain bearing capacity, and the water pressure resistance of the structure is further improved.

Furthermore, as the content of the viscoelastic material supplements and describes the bearing structure, the square honeycomb structure is formed by embedding and combining a plurality of partition boards which are distributed and arranged along the transverse direction and the longitudinal direction of the bottom plate, and the preparation is simple.

Furthermore, the thickness of the partition plate is 0.5-3 mm, the height of the partition plate is 21-51 mm, and the rigidity of the partition plate can be ensured so that the square honeycomb does not vibrate along with the viscoelastic material.

Furthermore, in order to ensure acoustic impedance mismatch between the honeycomb wall surface and the viscoelastic material and have certain bearing capacity, the square honeycomb structure selects metal such as steel and aluminum or composite materials such as carbon fiber and glass fiber.

Furthermore, the width of the cells is 10-30 mm, the selection of the width of the cells is related to the parameters of the viscoelastic material, and the width of the cells and the parameters of the viscoelastic material are matched with each other, so that good sound absorption performance is realized.

Further, the thickness h of the viscoelastic material filled in each cell₂The sound absorption structure is set to be 20-50 mm, so that the sound waves are guaranteed to have enough propagation distance in the structure, and the sound absorption performance at a low-frequency stage is effectively guaranteed.

Further, in order to improve the vibration of the viscoelastic material in the square honeycomb-rubber composite underwater sound absorption structure, an air layer is embedded between the rubber and the bottom plate, and the thickness of the air layer is 1-10 mm.

Further, in order to ensure sufficient sound absorption of the structure, the thickness h of the cover layer₃Is 1-10 mm.

Furthermore, the covering layer is made of viscoelastic materials, has acoustic properties similar to those of seawater, ensures that sound waves smoothly enter, is corrosion-resistant, and can protect the square honeycomb from being corroded by seawater.

Furthermore, the density of the viscoelastic material is 800-1400 kg/m³The main sound absorption function is achieved in the structure, the transverse wave loss factor of the viscoelastic material is 0.5 or above, so that the sufficient viscous effect is guaranteed between the viscoelastic material and the honeycomb wall surface, and the sufficient loss capacity is achieved for sound wave energy.

In conclusion, the sound absorption performance of the viscoelastic material can be improved to a great extent, more adjustable parameters including structural parameters and material parameters are provided in the aspect of design, the sound absorption performance can be adjusted correspondingly according to the requirements of actual working conditions, and the sound absorption device is simple in structure and easy to manufacture.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic view of an underwater sound absorbing structure of the present invention;

FIG. 2 is a honeycomb top and side view, wherein (a) is a top view and (b) is a side view;

fig. 3 is a schematic diagram of sound absorption coefficients of three embodiments of the underwater sound absorption structure of the present invention.

Wherein: 1. a cover layer; 2. a square honeycomb structure; 3. an air layer.

Detailed Description

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, not all, embodiments of the present 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.

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.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

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 square honeycomb composite underwater sound absorption structure with an air layer inside, which adopts metal or carbon fiber/glass fiber composite material to form a square honeycomb structure, and polyurethane or rubber and other viscoelastic materials are filled into a space formed by partition plates of the square honeycomb structure to be solidified. The bottom of the viscoelastic material is provided with an air layer to promote rubber vibration, and the upper surface of the structure is covered with a pure rubber covering layer to protect the square honeycomb structure from being eroded by seawater, so that compared with the viscoelastic material with the same thickness, the finally formed structure has the advantages that the sound absorption performance is greatly improved, and the sound absorption coefficient is larger than 0.8 in a wide frequency band range. And the formed structure has the property of difficult deformation under hydrostatic pressure, thereby realizing the underwater sound absorption structure which can resist hydrostatic pressure and has broadband sound absorption effect.

Referring to fig. 1 and 2, the square honeycomb composite underwater sound absorption structure with an air layer built-in according to the present invention includes a cover layer 1, a square honeycomb structure 2 and an air layer 3, wherein the square honeycomb structure 2 is disposed on a bottom plate, each cell of the square honeycomb structure 2 is filled with a viscoelastic material, the air layer 3 is disposed between the bottom of the viscoelastic material and the bottom plate, and the cover layer 1 is disposed on the top of the viscoelastic material.

The cover layer 1 is made of viscoelastic material, and the thickness h of the cover layer 1₃1-10 mm, as shown in FIG. 2.

The square honeycomb structure 2 comprises a plurality of partition plates, the partition plates are arranged on a bottom plate at intervals and are distributed on the bottom plate along the transverse direction and the longitudinal direction, two adjacent partition plates form a cell, the square honeycomb structure 2 is made of metal materials such as iron and aluminum or carbon fiber/glass fiber composite materials, the thickness t of each partition plate is 0.5-3 mm, and the height of each partition plate is 21-51 mm in order to guarantee certain requirements on bearing capacity, weight and the like.

The width a of each unit cell in the square honeycomb structure 2 is 10-30 mm, as shown in FIG. 2.

The density of the viscoelastic material is 800-1400 kg/m³The transverse wave sound velocity of the viscoelastic material is 500-2000 m/s, and the transverse wave loss factor of the viscoelastic material is 0.01-0.3; the longitudinal wave sound velocity of the viscoelastic material is 30-300 m/s, and the longitudinal wave loss factor of the viscoelastic material is larger than 0.5.

Wherein the viscoelastic material is used as sound absorbing material for absorbing sound wave energy, and comprises rubber or polyurethane.

Thickness h of viscoelastic material filled in each cell₂20-50 mm, as shown in FIG. 2.

The air layer 3 is filled with air, and the thickness h of the air layer 3₁1-10 mm, as shown in FIG. 2.

The thickness h of the square honeycomb-rubber composite underwater sound absorption structure is 22-70 mm, and is shown in figure 2.

The covering layer 1 covered on the upper surface of the square honeycomb composite underwater sound absorption structure with the built-in air layer plays a role in protecting the honeycomb from being corroded by seawater; in the formed square honeycomb rubber composite underwater sound absorption structure with the built-in air layer, the square honeycomb structure 2 plays a role in improving the sound absorption performance of a viscoelastic material and transferring loads such as water pressure and the like, and the air layer 3 arranged at the bottom can improve the sound absorption performance; the sound absorption coefficient of the sound absorption material is larger than 0.8 within the range of 1100-10000 Hz, the average sound absorption coefficient is larger than 0.9, and compared with a viscoelastic material with the same thickness, the sound absorption performance is greatly improved. The reason is that steel has a modulus much greater than rubber, and steel plates can be considered as stiff relative to rubber. The sound wave causes the rubber to vibrate, and because the vibration of the connection position of the rubber and the honeycomb is limited, a strong shearing action is generated near the wall surface of the honeycomb, so that the sound wave energy is lost. The bottom air layer releases the constraint of the bottom on the vibration of the rubber, and increases the intersecting vibration, thereby effectively improving the sound absorption performance of the low-frequency-order structure.

In addition, the square honeycomb composite underwater sound absorption structure with the built-in air layer also meets the requirement that the sound absorption performance is not easy to decline when the sound absorption performance is maintained under high hydrostatic pressure; simple structure, maneuverability are strong.

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.

Example 1

Metal steel: it is characterized by a density of 7850kg/m3, a Young's modulus of 2.05GPa and a Poisson's ratio of 0.28.

Viscoelastic material: it is characterized by a density of 1000kg/m³The longitudinal wave velocity is 1000m/s, the longitudinal wave loss factor is 0.3, the transverse wave velocity is 100m/s, and the transverse wave loss factor is 0.9.

Water: it is characterized by a density of 1000kg/m³The speed of sound is 1500 m/s.

Air: it is characterized by a density of 1.29kg/m³The speed of sound is 340 m/s.

Example structure dimensions:

cell size of honeycomb: a is 20 mm. Thickness of the metal plate: t is 1 mm. Thickness of air layer: h is₁5 mm. Thickness of the honeycomb rubber mixing layer: h is₂40 mm. Thickness of upper pure rubber cover layer: h is₃＝5mm。

Example 2

Materials for examples:

metal steel: it is characterized by a density of 7850kg/m3, a Young's modulus of 2.05GPa and a Poisson's ratio of 0.28.

Viscoelastic material: it is characterized by a density of 900kg/m³The longitudinal wave velocity is 1200m/s, the longitudinal wave loss factor is 0.09, the transverse wave velocity is 100m/s, and the transverse wave loss factor is 0.9.

Water: it is characterized by a density of 1000kg/m³The speed of sound is 1500 m/s.

Air: it is characterized by a density of 1.29kg/m³The speed of sound is 340 m/s.

Example structure dimensions:

cell size of honeycomb: a is 25 mm. Thickness of the metal plate: t is 1 mm. Thickness of air layer: h is₁6 mm. Thickness of the honeycomb rubber mixing layer: h is₂50 mm. Thickness of upper pure rubber cover layer: h is₃＝4mm。

Example 3

Materials for examples:

metal steel: it is characterized by a density of 7850kg/m3, a Young's modulus of 2.05GPa and a Poisson's ratio of 0.28.

Viscoelastic material: it is characterized by a density of 800kg/m³The longitudinal wave velocity is 800m/s, the longitudinal wave loss factor is 0.15, the transverse wave velocity is 80m/s, and the transverse waveThe loss factor is 0.8.

Water: it is characterized by a density of 1000kg/m³The speed of sound is 1500 m/s.

Air: it is characterized by a density of 1.29kg/m³The speed of sound is 340 m/s.

Example structure dimensions:

cell size of honeycomb: a is 20 mm. Thickness of the metal plate: t is 1 mm. Thickness of air layer: h is₁4 mm. Thickness of the honeycomb rubber mixing layer: h is₂35 mm. Thickness of upper pure rubber cover layer: h is₃＝2mm。

Comparative example 1 is a uniform rubber material having the same thickness as in example, and comparative example 2 is a honeycomb rubber hybrid structure having no air layer inside, and the total thickness is kept uniform. To ensure the objectivity of the control, the material parameters were kept consistent with the examples.

Theoretical calculation and numerical simulation are carried out by adopting the materials and the structural dimensions, and the comparison of the sound absorption coefficients of the examples and the comparative examples is given as follows:

and calculating the sound absorption coefficients of the two structures between 0 and 10000Hz and the uniform comparison group.

Referring to fig. 3, a dotted line represents a sound absorption coefficient of a viscoelastic material having a uniform thickness, a dotted line represents a sound absorption coefficient of a honeycomb rubber hybrid structure, and a solid line represents a sound absorption coefficient of a tetragonal honeycomb rubber composite underwater sound absorption structure having an air layer built therein. As can be seen from the figure, compared with the viscoelastic material with the same thickness, the sound absorption structure provided by the invention is greatly improved within 0-10000 Hz. The concrete expression is as follows:

the sound absorption coefficient of the sound absorption material in the embodiment 1 is more than 0.8 when 1100-10000 Hz is obtained, and the average sound absorption coefficient is more than 0.9.

The sound absorption coefficient of the embodiment 2 reaches more than 0.8 when 1500-4800 Hz, and the average sound absorption coefficient reaches more than 0.8.

The sound absorption coefficient of the embodiment 3 reaches more than 0.8 when the sound absorption coefficient is 2000-6100 Hz, and the average sound absorption coefficient reaches more than 0.75

The result shows that the sound absorption performance in a wide frequency range can be greatly improved by controlling the size and the thickness of the honeycomb and selecting rubber materials with different physical parameters in a parameter value range. Among them, the sound absorption bandwidth of example 1 is the widest, and the average sound absorption coefficient is the best.

In conclusion, the square honeycomb composite underwater sound absorption structure with the built-in air layer has the following advantages:

1. the sound absorption coefficients of the sound absorption device are all above 0.8 in 1100-10000 Hz, the average sound absorption coefficient is above 0.9, and the sound absorption device meets the requirement of effective sound absorption in a wide frequency band;

2. the square honeycomb structure is simple, the mixing process with rubber is simple, and the processing is convenient;

3. the mechanical property of the whole structure can be changed by changing the parameters of the honeycomb such as material, thickness and the like, and the honeycomb can meet the requirements of different occasions.

4. The upper rubber layer effectively protects the metal honeycomb from seawater corrosion, keeps the surface smooth and effectively reduces the surface resistance.

In conclusion, the square honeycomb composite underwater sound absorption structure with the built-in air layer can be used for manufacturing an underwater sound absorption covering layer, the sound energy loss capability of a viscoelastic material is improved through the structural design, the underwater sound absorption structure with the pressure bearing capability is realized, and the underwater sound absorption structure has a wide engineering application prospect.

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.