Multifunctional triangular grating underwater sound absorption structure with annular inner insertion pipe

Abstract

The multifunctional triangular grating underwater sound absorption structure comprises a plurality of cells arranged in an array mode, each cell comprises a triangular prism with a cavity, a top plate of each triangular prism is provided with an open hole, a pipeline is embedded in each open hole, and a supporting column is embedded in each pipeline; the structure can be used for manufacturing an underwater sound absorption layer, has excellent underwater sound absorption capacity and pressure bearing capacity, can be selected according to working condition requirements by adjusting the structure size, and has wide engineering application prospects.

Description

Technical Field

[0001] The invention belongs to the field of underwater sound-absorbing composite structures, and in particular relates to an underwater sound-absorbing structure with a multifunctional triangular grid having an annular inner-inserted pipe. Background Art

[0002] Underwater sound absorbing materials are a special type of acoustic material that can be used to absorb sound waves within the target frequency band to reduce reflected sound waves and avoid being detected by the sonar detection system. The main base material of underwater sound absorbing materials is viscoelastic material, which is a composite material with viscous and elastic properties. It can consume sound energy through internal viscous loss and elastic deformation. When sound waves pass through viscoelastic materials, the molecular chains inside the material will rub against each other, generating internal friction, thereby converting sound energy into heat energy. However, the efficiency of viscoelastic materials in dissipating sound energy depends on their thickness and the wavelength of the sound wave. When the thickness is small or the wavelength of the sound wave is long, the efficiency of sound energy dissipation is low. Therefore, it is a great challenge to achieve sound absorption of low-frequency sound waves under limited thickness.

[0003] In order to solve the absorption of low-frequency sound waves under limited thickness, the more mature method is to add local oscillators with higher density to viscoelastic materials or design Helmholtz resonators. The local resonator sound absorption layer using local oscillators can achieve good sound absorption effect at the resonance frequency, but the disadvantage is that the coupling mechanism between the oscillators of the local resonator is relatively complicated, and it is difficult to achieve broadband sound absorption effect; the Helmholtz resonator consists of a closed cavity and a narrow channel connected to it. When the frequency of the sound wave matches the natural frequency of the resonant cavity, the sound wave will resonate in the cavity, thereby enhancing the absorption of energy, but the pressure bearing capacity is poor. Therefore, although the design of underwater sound absorbing materials has made great progress, it is still a problem to be solved to achieve high-efficiency and pressure-resistant low-frequency sound absorption performance under limited thickness. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an underwater sound absorption structure with a multifunctional triangular grid with an annular inner tube in view of the deficiencies in the above-mentioned prior art, which is used to solve the technical problems of poor low-frequency sound absorption performance and poor pressure bearing capacity of traditional underwater sound-absorbing covering layers.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides an underwater sound-absorbing structure with a multifunctional triangular grid having an annular inner tube, comprising a plurality of cells arranged in an array, wherein the cells include a triangular prism having a cavity, an opening is provided on the top plate of the triangular prism, a pipe is embedded in the opening, and a pillar is embedded in the pipe.

[0006] Preferably, a layer of viscoelastic material is provided on the inner wall of the triangular prism.

[0007] Preferably, the thickness of the viscoelastic material is 1-8 mm.

[0008] Preferably, the pipe is connected to the lower surface of the top plate.

[0009] Preferably, the pipeline is connected to the lower surface of the top plate by welding or gluing.

[0010] Preferably, the support pillar is connected to the upper surface of the bottom plate of the triangular prism.

[0011] Preferably, the support column is connected to the upper surface of the bottom plate of the triangular prism by welding or gluing.

[0012] Preferably, the opening, the pipe and the support are coaxially arranged.

[0013] Preferably, the wall thickness of the triangular prism is 0.5-4 mm, the height of the triangular prism is 40-60 mm, and the width of each wall of the triangular prism is 40-60 mm.

[0014] Preferably, the length of the pipe is smaller than the height of the triangular prism.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides an underwater sound-absorbing structure with a multifunctional triangular grid having an annular inner tube. A plurality of triangular prism walls are provided on the bottom plate, and a layer of viscoelastic material is covered on the triangular prism wall. The top plate is a perforated plate and connected to a pipe. A coaxial pillar is arranged in the pipe to form a Helmholtz resonator with an annular inner tube. When the frequency of the sound wave matches the natural frequency of the resonance cavity, the sound wave will resonate in the cavity, and the viscoelastic material covered on the triangular prism wall will produce compression vibration under the action of the sound wave. The molecular chains inside the viscoelastic material will rub against each other, produce internal friction, and convert a large amount of sound energy into heat energy to achieve the absorption of the sound wave. On the other hand, under the excitation of the resonant frequency, the fluid in the annular embedded pipe will produce reciprocating motion along the axial direction of the pipe, and under the action of the viscous resistance of water, the sound energy will be converted into heat energy to achieve the dissipation of sound energy. In addition, the lower surface of the pillar is connected to the bottom plate, and the upper surface of the pillar is coplanar with the upper surface of the top plate. When the underwater anechoic layer is subjected to pressure load, the pillar can share part of the pressure, thereby improving the bearing capacity of the structure.

[0016] Furthermore, the thickness of the top plate is 2-4 mm, which can ensure that under the excitation frequency, the stiffness of the top plate prevents the top plate from vibrating together with the viscoelastic material.

[0017] Furthermore, the thickness of the viscoelastic material covering layer is related to the diameter and length of the pipe, and the two cooperate with each other to achieve good sound absorption performance.

[0018] Furthermore, in order to ensure that the structure has sufficient sound absorption capacity, the height of the triangular prism wall is 40~60 mm.

[0019] In summary, the present invention can be used to manufacture underwater sound-absorbing covering layers, which have excellent low-frequency underwater sound absorption performance and good pressure-bearing capacity. The structural parameters and material parameters are highly adjustable and can be selected according to actual working conditions. It has broad engineering application prospects.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the underwater sound absorbing structure of the present invention.

[0022] Figure 2 Schematic diagram of the structure of a triangular prism, wherein (a) is a side view and (b) is a cross-sectional view; FIG3 (a) is a comparison diagram of the sound absorption coefficient of the underwater sound absorbing structure of the present invention in Example 1 and the underwater sound absorbing structure of the present invention without the support pillars; FIG3( b ) is a comparison diagram of the sound absorption coefficients of the underwater sound absorbing structure of the present invention in Example 2 and the underwater sound absorbing structure of the present invention without the support pillars; FIG3( c ) is a comparison diagram of the sound absorption coefficients of the underwater sound absorbing structure of the present invention in Example 3 and the underwater sound absorbing structure of the present invention without the support pillars; Among them: 1. Pillar; 2. Pipe; 3. Viscoelastic material; 4. Triangular prism wall. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one side", "one end", "one side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0030] The present invention provides an underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube. A layer of viscoelastic material is covered on the inner wall surface of the inner cavity of the triangular prism. The top plate of the triangular prism and the upper surface of the triangular prism are connected together by welding or gluing to form a closed cavity.

[0031] The lower surface of the top plate is connected with a pipeline, and coaxially arranged pillars are arranged inside the pipeline, and the pipeline and the pillars form an annular pipeline.

[0032] The triangular prism wall, viscoelastic rubber, top plate, pipe and pillar form a Helmholtz resonator with an embedded annular pipe, and a viscoelastic material coating is provided inside the Helmholtz resonator to further enhance the sound wave dissipation capability and achieve a peak sound absorption coefficient greater than 0.9 at a sound absorption peak below a frequency of 1000 Hz.

[0033] And under the joint action of the triangular prism wall and the pillar, the pressure-bearing capacity of the underwater sound-absorbing layer is greatly improved, thereby realizing a multifunctional composite underwater sound-absorbing structure with excellent low-frequency underwater sound absorption performance and good pressure-bearing capacity.

[0034] See also Figure 1 The present invention provides an underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube, comprising a support 1, a pipe 2, a viscoelastic material 3 and a triangular prism wall 4, wherein: The triangular prism walls are periodically arranged on the bottom plate to form a triangular grid plate. The triangular prism walls are covered with a layer of viscoelastic material to improve the sound wave dissipation capacity of the underwater anechoic layer. The annular pipe formed by the pipe and the pillar serves as a narrow channel of the Helmholtz resonator, which can also dissipate sound energy at the excitation frequency. In addition, the triangular prism walls and the pillars enhance the pressure bearing capacity of the underwater anechoic layer.

[0035] Among them, the width of each triangular prism cell is 40~60 mm.

[0036] The support 1 is coaxial with the pipe 2, the lower surface of the support is connected to the bottom plate, the upper surface of the support is coplanar with the upper surface of the top plate, and the diameter of the support is 4-10 mm.

[0037] Both ends of the support are connected to the top plate and the bottom plate by welding or gluing.

[0038] Pipe 2 is connected to the lower surface of the top plate. The hole on the top plate is concentric with the circular inner wall of the pipe and has the same diameter, which is 6-12 mm. The length of the pipe is 5-45 mm.

[0039] The density of viscoelastic material 3 is 800~1400 kg / m 3 ; Young's modulus is 5~20 MPa, Poisson's ratio is greater than 0.49, and loss factor is 0.01~0.8.

[0040] The thickness of the covering layer of the viscoelastic material 3 is 1 to 8 mm.

[0041] The triangular prism wall 4 is made of metal material. To ensure a certain bearing capacity, the wall thickness of the triangular prism is 0.5-4 mm, the height of the triangular prism is 40-60 mm, and the width of each wall of the triangular prism is 40-60 mm.

[0042] The overall thickness of the underwater anechoic layer is 42~70 mm.

[0043] The underwater sound absorption structure of the multifunctional triangular grid with an annular inner tube of the present invention can achieve a peak sound absorption coefficient of more than 0.9 for the sound absorption peak below 1000 Hz. Compared with viscoelastic materials of the same thickness, the sound absorption performance is greatly improved; compared with the sound absorption metamaterial without pillars in the chamber, the compression strength is also significantly improved.

[0044] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] Example 1 Metal steel: density is 7850 kg / m 3 , Young’s modulus is 200 GPa, and Poisson’s ratio is 0.3.

[0046] Viscoelastic material 1: density 1100 kg / m 3 , Young's modulus is 10 MPa, Poisson's ratio is 0.49, and loss factor is 0.3.

[0047] Water: density is 1000 kg / m3, speed of sound is 1500 m / s.

[0048] Example structure size: Overall thickness of underwater anechoic layer: H =52 mm; Height of triangular prism wall: h =48 mm; Top plate thickness: t 1=2 mm; Thickness of triangular prism wall: t 2=1mm; Viscoelastic material cover thickness: t r =2.8 mm; Diameter of the pillar: d 1 = 6 mm; Annular inner tube outer diameter: d 2 = 9 mm; Length of circular inner tube: l =43 mm; Pipe wall thickness: t n =0.5 mm.

[0049] Example 2 Metal steel: density is 7850 kg / m 3 , Young’s modulus is 200 GPa, and Poisson’s ratio is 0.3.

[0050] Viscoelastic material 2: density 1100 kg / m 3 , Young's modulus is 10 MPa, Poisson's ratio is 0.49, and loss factor is 0.3.

[0051] Water: density is 1000 kg / m3, speed of sound is 1500 m / s.

[0052] Example structure size: Overall thickness of underwater anechoic layer: H =52 mm; Height of triangular prism wall: h =48 mm; Top plate thickness: t 1=2 mm; Thickness of triangular prism wall: t 2=1mm; Viscoelastic material cover thickness: t r =7 mm; Diameter of the pillar: d 1=8 mm; Annular inner tube outer diameter: d 2 = 9.1 mm; Length of circular inner tube: l =40 mm; Pipe wall thickness: t n =0.5 mm.

[0053] Example 3 Metal steel: density is 7850 kg / m 3 , Young’s modulus is 200 GPa, and Poisson’s ratio is 0.3.

[0054] Viscoelastic material 3: density 900 kg / m 3 , Young's modulus is 5 MPa, Poisson's ratio is 0.49, and loss factor is 0.3.

[0055] Water: Density 1000 kg / m 3 , speed of sound 1500 m / s.

[0056] Example structure size: Overall thickness of underwater anechoic layer: H =52 mm; Height of triangular prism wall: h =48 mm; Top plate thickness: t 1=2 mm; Thickness of triangular prism wall: t 2=2mm; Viscoelastic material cover thickness: t r =4 mm; Diameter of the pillar: d 1=8 mm; Annular inner tube outer diameter: d 2 = 10 mm; Length of circular inner tube: l =23 mm; Pipe wall thickness: t n =0.5 mm.

[0057] The three embodiments all use the same structure as the underwater sound absorption structure of the present invention without pillars as the control group, and the material parameters and total thickness are consistent with the corresponding embodiments. The sound absorption coefficient of the structure at 0-1000Hz is calculated and the stress-strain curve is drawn by theoretical calculation and numerical simulation.

[0058] Please refer to 3 (a) to (c), which are comparison diagrams of the sound absorption coefficient curves and stress-strain curves of the three embodiments and the control group. The black solid line is a triangular prism wall sound absorption structure with pillars, and the black dotted line is a triangular prism wall sound absorption structure without pillars.

[0059] The sound absorption structure proposed in the present invention has obvious sound absorption advantages at low frequencies, wherein the peak frequency of Example 1 moves to the low frequency by 150 Hz, and the yield strength is increased by 16%, wherein the peak frequency of Example 2 moves to the low frequency by 300 Hz, and the yield strength is increased by 33%, wherein the peak frequency of Example 3 moves to the low frequency by 150 Hz, and the yield strength is increased by 18%.

[0060] The present invention has the following technical effects: 1. It has excellent low-frequency sound absorption performance.

[0061] The structure of the present invention can achieve a peak sound absorption coefficient of greater than 0.9 at an absorption peak below a frequency of 1000 Hz, and the sound absorption performance is significantly improved compared to a uniform viscoelastic material layer of equal thickness.

[0062] 2. It has good carrying capacity.

[0063] The triangular prism wall panels and pillars are both made of steel. Under the action of pressure loads, the triangular prism wall panels and pillars each bear a part of the load, thereby ensuring the bearing capacity of the structure.

[0064] 3. It has adjustable sound absorption peak frequency.

[0065] The thickness of the viscoelastic material covering layer, the inner and outer diameters and length of the annular inner tube, and the appropriate combination of viscoelastic material parameters can change the peak frequency of the sound absorption peak, and the specific selection can be made according to the working conditions.

[0066] In summary, the underwater sound absorption structure with a multifunctional triangular grid having an annular inner tube can be used to manufacture a pressure-resistant underwater sound-absorbing covering layer, and has excellent underwater low-frequency sound absorption performance and pressure bearing capacity. In terms of design, the combination of structural parameters and material parameters is flexible and can be selected according to actual working conditions, and has a wide range of engineering application prospects.

[0067] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. An underwater sound-absorbing structure with a multifunctional triangular grid having an annular inner tube, characterized in that: It comprises a plurality of cells arranged in an array, wherein the cells comprise a triangular prism with a cavity, a top plate of the triangular prism is provided with an opening, a pipe is embedded in the opening, and a pillar is embedded in the pipe.

2. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1 is characterized in that: A layer of viscoelastic material is arranged on the inner wall of the triangular prism.

3. The viscoelastic material lined Helmholtz cavity underwater sound absorbing structure according to claim 2, characterized in that: The thickness of the viscoelastic material is 1-8 mm.

4. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1 is characterized in that: The pipe is connected to the lower surface of the top plate.

5. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1 is characterized in that: The pipeline is connected to the lower surface of the top plate by welding or gluing.

6. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1, characterized in that: The support column is connected to the upper surface of the bottom plate of the triangular prism.

7. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1 is characterized in that: The support column is connected to the upper surface of the bottom plate of the triangular prism by welding or gluing.

8. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1 is characterized in that: The opening, the pipe and the support are coaxially arranged.

9. The underwater sound absorbing structure with a multifunctional triangular grid having an annular inner tube according to claim 1, characterized in that: The wall thickness of the triangular prism is 0.5-4 mm, the height of the triangular prism is 40-60 mm, and the width of each wall of the triangular prism is 40-60 mm.

10. The viscoelastic material lined Helmholtz cavity underwater sound absorbing structure according to claim 1, characterized in that: The length of the pipe is smaller than the height of the triangular prism.

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