High-pressure-bearing composite material structure for underwater low-frequency sound absorption

Abstract

The application belongs to the technical field of vibration and noise control, and particularly relates to a high-pressure composite material structure for underwater low-frequency sound absorption. The structure comprises a perforated panel, a liquid cavity framework, an elastic film, a mass block, an air cavity framework and a backing bottom plate. The perforated panel and the elastic film are respectively attached to the upper and lower sides of the liquid cavity framework, the air cavity framework is attached to the lower side of the elastic film, and the backing bottom plate is located at the bottom of the air cavity framework. The application is easily applicable to structure surfaces of different sizes through periodic structure extension, and can be typically applied to underwater vehicle acoustic cover layers and water pipeline silencers, and has good engineering practicability. Meanwhile, the application has high integrated design degree, and raw materials are easy to obtain and easy to prepare, and has good engineering applicability.

Description

Technical Field

[0001] This invention belongs to the field of vibration and noise control technology, specifically relating to a high-pressure-bearing composite material structure for underwater low-frequency sound absorption. Background Technology

[0002] In underwater environments, sound waves, due to their long propagation distance and high speed, are currently the primary means of underwater target detection. However, the radiated noise energy of underwater vehicles is typically concentrated in the low-frequency band, and low-frequency sound waves have long wavelengths and slow propagation attenuation, leading to a gradual development of sonar detection technology towards low-frequency sound detection capabilities. To reduce detectability, underwater vehicles usually need to have sound-absorbing materials applied to their surfaces to absorb some of the incident and self-radiated sound energy. Traditional underwater sound-absorbing materials mainly dissipate sound energy through intermolecular friction of viscoelastic materials. Their absorption frequency band depends on the relationship between the material's characteristic dimensions and the sound wave wavelength. However, due to the long wavelength of underwater low-frequency sound waves, traditional sound-absorbing materials are essentially unable to achieve low-frequency sound absorption under limited thickness constraints. In recent years, with the introduction of the concept of localized resonant phonon crystals, acoustic metamaterial configurations that can achieve "small-size absorption of large wavelengths" by controlling the bandgap width of localized resonant units have been proposed. However, two major problems generally exist: first, insufficient low-frequency sound absorption performance. For example, while thin-film acoustic metamaterials with relatively excellent low-frequency sound absorption performance can reduce the sound absorption frequency to below 1kHz, their sound absorption performance below 200Hz is still very limited. Second, insufficient pressure resistance. Currently, most sound-absorbing materials mainly use a viscoelastic matrix to encapsulate a mass block to reduce the resonant frequency. However, under high water pressure, viscoelastic materials are prone to deformation and hardening, reducing low-frequency sound absorption performance. Therefore, although some progress has been made in the design of underwater sound-absorbing materials, acoustic material structures that simultaneously achieve both low-frequency sound absorption performance and high pressure resistance remain a problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned deficiencies or improvement needs of the prior art by providing a high-pressure-bearing composite material structure for underwater low-frequency sound absorption, which enhances the pressure-bearing capacity of underwater sound-absorbing materials and improves the sound absorption effect for low-frequency underwater sounds.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A high-pressure-bearing composite material structure for underwater low-frequency sound absorption includes a perforated panel 1, a liquid cavity skeleton 2, an elastic film 3, a mass block 4, an air cavity skeleton 5, and a backing plate 6; the perforated panel 1 and the elastic film 3 are respectively attached to the upper and lower sides of the liquid cavity skeleton 2, the air cavity skeleton 5 is attached to the lower side of the elastic film 3, and the backing plate 6 is located at the bottom of the air cavity skeleton 5.

[0006] The liquid cavity skeleton 2 and the gas cavity skeleton 5 are flat plate structures with columnar channels evenly distributed inside, and the columnar channels of the liquid cavity skeleton 2 and the gas cavity skeleton 5 correspond one-to-one; the perforated panel 1 has a plurality of through-hole arrays evenly distributed, and the through-hole arrays correspond one-to-one with the columnar channels; there are multiple mass blocks 4, which are respectively located in the cavity formed by the columnar channels and the elastic film 3, and the mass blocks 4 are adhered to the elastic film 3.

[0007] In a further improved or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the upper and lower end faces of the air cavity skeleton 5 are respectively closed by an elastic film 3 and a backing plate 6, and the lower surface of the backing plate 6 is the mounting surface of the high pressure-bearing composite material structure for underwater low-frequency sound absorption.

[0008] In a further improved or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the perforated panel 1 is made of metal or fiberglass, the diameter of the through holes in the perforated panel 1 is 0.5mm to 10mm, and the spacing between the through holes is 5mm to 50mm.

[0009] In a further improved or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the columnar channels form a periodically arranged columnar channel structure, and the cross-section of the columnar channels is a regular hexagon or a regular quadrilateral.

[0010] In a further improved or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the liquid cavity skeleton 2 and the air cavity skeleton 5 are made of metal, the side length of the columnar channels of the liquid cavity skeleton 2 and the air cavity skeleton 5 is 10mm~100mm, and the wall thickness between adjacent columnar channels is 1mm~10mm.

[0011] In a further improvement or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the elastic film (3) is a composite rubber material consisting of a rubber substrate and a reinforcing fiber skeleton.

[0012] In a further improvement or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the through holes on the perforated panel 1, the columnar channels on the liquid cavity skeleton 2, and the upper end face of the elastic film 3 form a uniformly arranged semi-closed liquid cavity. Each semi-closed liquid cavity is connected to the external water body through a through hole, and the mass block 4 is located at the center of the bottom of the semi-closed liquid cavity.

[0013] The lower end face of the elastic film 3, the columnar channel on the air cavity skeleton 5, and the upper end face of the back substrate 6 form an air cavity that is directly opposite the semi-closed liquid cavity. The skeleton wall between adjacent air cavities is provided with a gap so that the gas between each air cavity can be connected.

[0014] In a further improvement or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the backing substrate 6 is made of metal.

[0015] In a further improved or preferred embodiment of the aforementioned high pressure-bearing composite material structure for underwater low-frequency sound absorption, the perforated panel 1 and the liquid cavity skeleton 2 are integrally molded or threadedly connected. The elastic film 3 is connected to the liquid cavity skeleton 2 and the air cavity skeleton 5 by vulcanization. The liquid cavity skeleton 2 and the air cavity skeleton 5 are fixedly connected by threads. The air cavity skeleton 5 and the backing substrate 6 are integrally molded or threadedly connected.

[0016] The above-mentioned improved technical solutions can be combined with each other as long as they do not conflict with each other.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. Combining the low-frequency sound absorption characteristics of perforated structures and thin-film local resonant materials can enhance the overall structure's sound absorption effect against underwater low-frequency noise;

[0019] 2. The elastic membrane is supported by two layers of skeletons, namely the liquid cavity skeleton and the gas cavity skeleton. At the same time, the elastic membrane is made of composite rubber material with rubber base and reinforcing fiber skeleton integrally formed, which improves the pressure bearing capacity of the overall structure.

[0020] 3. By adjusting parameters such as the mass of the mass block, the diameter of the perforation, and the size of the periodic liquid / gas cavity, the sound absorption frequency band of the overall structure can be easily changed and broadened;

[0021] 4. By utilizing the high compressibility of air and the high elasticity of thin film materials, the overall structural thickness can be significantly reduced while maintaining the same sound absorption effect, resulting in a highly compact structure;

[0022] This invention, through periodic structural extension, is easily applicable to structural surfaces of different sizes. It can typically be applied to acoustic coverings for underwater vehicles and silencers for water pipelines, demonstrating excellent engineering practicality. At the same time, the invention features a high degree of integrated structural design, readily available raw materials, and ease of fabrication, further enhancing its engineering applicability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a high-pressure-bearing composite material structure used for underwater sound absorption;

[0024] Figure 2 This is a schematic diagram of the arrangement of the through-hole array, columnar channel, and gun body structure in the embodiment;

[0025] Figure 3 This is a schematic diagram of the composition of the elastic film material in the embodiment;

[0026] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0027] 1. Perforated panel; 2. Liquid cavity skeleton; 3. Elastic film; 4. Mass block; 5. Gas cavity skeleton; 6. Backing substrate; 7. Bolt; 2-1. Liquid cavity skeleton wall; 2-2. Semi-closed liquid cavity; 3-1. Rubber substrate; 3-2. Reinforcing fiber skeleton; 5-1. Gas cavity skeleton wall; 5-2. Gas cavity; 5-3. Gas cavity notch. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] like Figures 1-3 As shown, as a preferred embodiment of the present invention, a high pressure-bearing composite material structure for underwater sound absorption includes a perforated panel 1, a liquid cavity skeleton 2, an elastic film 3, a mass block 4, an air cavity skeleton 5, and a backing plate 6; the perforated panel 1 and the elastic film 3 are respectively attached to the upper and lower sides of the liquid cavity skeleton 2, the air cavity skeleton 5 is attached to the lower side of the elastic film 3, and the backing plate 6 is located at the bottom of the air cavity skeleton 5.

[0030] The liquid cavity skeleton 2 and the gas cavity skeleton 5 are flat plate structures with columnar channels evenly distributed inside, and the columnar channels of the liquid cavity skeleton 2 and the gas cavity skeleton 5 correspond one-to-one; the perforated panel 1 has a plurality of through holes evenly distributed on it, and the through hole arrays correspond one-to-one with the columnar channels. The perforated panel 1 is provided with through holes to allow external incident sound waves to enter the interior of the structure and generate the viscous dissipation effect of the sound waves; there are multiple mass blocks 4, which are respectively located in the cavity formed by the columnar channels and the elastic film 3, and the bottom of the mass blocks 4 is adhered to the elastic film 3.

[0031] In this application, multiple columnar channel structures are uniformly and periodically arranged inside the liquid cavity skeleton and the air cavity skeleton. Considering structural stability and sound absorption performance, the cross-section of the columnar channels in this application is a regular hexagon or a regular quadrilateral.

[0032] As a preferred approach, in order to improve structural strength and enhance pressure resistance, the perforated panel 1 in this embodiment is made of metal and is integrally molded with the liquid cavity skeleton 2, which is also made of metal. In other embodiments, in order to improve sound penetration, the perforated panel 1 can also be made of materials with good sound transmission properties, such as fiberglass.

[0033] Considering the underwater sound wave propagation characteristics, in order to better absorb sound waves and prevent underwater foreign objects from entering the cavity while ensuring structural stability, as a preferred method, the diameter of the through holes in the perforated panel is set between 0.5mm and 10mm, and the spacing between the through holes is set between 5mm and 50mm.

[0034] To improve structural strength, the liquid cavity skeleton and the gas cavity skeleton are made of metal. The elastic membrane is a composite rubber material, including a rubber base and a reinforcing fiber skeleton; the perforated panel, the liquid cavity skeleton, and the elastic membrane enclose a series of periodically arranged semi-enclosed liquid cavities, each of which is connected to the external water body through a through hole in the perforated panel.

[0035] Preferably, the side length of the columnar channels of the liquid cavity skeleton and the gas cavity skeleton is 10mm~100mm, and the skeleton wall thickness between adjacent columnar channels is 1mm~10mm.

[0036] Based on the above structural design, this application integrates two sound-absorbing and vibration-damping structures: a perforated vibration-damping structure and a thin-film local resonance structure. Sound wave absorption is achieved through a water cavity in which the outer layer directly contacts the water body. While ensuring good low-frequency sound absorption characteristics, it can effectively enhance the sound absorption effect of underwater structures on underwater low-frequency noise. At the same time, the overall structure is more stable and efficient, and can be applied to various underwater shell and panel structures.

[0037] The liquid cavity skeleton and the gas cavity skeleton form two layers of skeleton support for the elastic membrane. The elastic membrane can be made of composite rubber material with rubber base and reinforcing fiber skeleton integrally molded, which can further improve the pressure bearing capacity of the overall structure.

[0038] The integrated structure enables better sealing and isolation, ensuring sufficient watertightness when used as an underwater shell or other structure. Through the sound focusing of the outer wading cavity, the energy dissipation of the mass block through resonance, and the elastic buffering of the inner air cavity, a multi-layer sound absorption and vibration reduction effect is achieved, effectively enhancing the underwater sound absorption capability of the structure. Based on this structure, a multi-layer high-strength shell support is formed.

[0039] As a preferred embodiment, in order to improve the integrity of the structure, achieve better sealing effect and stronger support and connection strength, the perforated panel and the liquid cavity skeleton can be integrally molded or threadedly connected. The elastic film is connected to the liquid cavity skeleton and the gas cavity skeleton by vulcanization. The liquid cavity skeleton and the gas cavity skeleton are fixedly connected by threads. The gas cavity skeleton and the backing substrate are integrally molded or threadedly connected.

[0040] The above-mentioned improved technical solutions can be combined and used together as long as they do not conflict with each other, so as to meet the different requirements for support strength, sealing performance and structural stability under different usage environments. They are highly flexible and easy to configure.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption, characterized in that, It includes a perforated panel (1), a liquid cavity skeleton (2), an elastic film (3), a mass block (4), a gas cavity skeleton (5), and a backing plate (6); the perforated panel (1) and the elastic film (3) are respectively attached to the upper and lower sides of the liquid cavity skeleton (2), the gas cavity skeleton (5) is attached to the lower side of the elastic film (3), and the backing plate (6) is located at the bottom of the gas cavity skeleton (5); The liquid cavity skeleton (2) and the gas cavity skeleton (5) are flat plate structures with columnar channels evenly distributed inside. The columnar channels of the liquid cavity skeleton (2) and the gas cavity skeleton (5) correspond one-to-one. Multiple through-hole arrays are evenly distributed on the perforated panel (1). The through-hole arrays correspond one-to-one with the columnar channels. There are multiple mass blocks (4) and they are respectively located in the cavity formed by the columnar channels and the elastic film (3). The bottom of the mass block (4) is attached to the elastic film (3).

2. The high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claim 1, characterized in that, The upper and lower end faces of the air cavity skeleton (5) are respectively sealed by an elastic film (3) and a backing plate (6). The lower surface of the backing plate (6) is the mounting surface of a high pressure-bearing composite material structure for underwater low-frequency sound absorption.

3. The high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claim 1, characterized in that, The perforated panel (1) is made of metal or fiberglass. The diameter of the through holes in the perforated panel (1) is 0.5mm~10mm, and the spacing between the through holes is 5mm~50mm.

4. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claim 1, characterized in that, The columnar channels form a periodically arranged columnar honeycomb structure, and the cross-section of the columnar channels is a regular hexagon or a regular square.

5. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claim 1, characterized in that, The liquid cavity skeleton (2) and the air cavity skeleton (5) are made of metal. The side length of the columnar channel of the liquid cavity skeleton (2) and the air cavity skeleton (5) is 10mm~100mm, and the wall thickness between adjacent columnar channels is 1mm~10mm.

6. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claim 1, characterized in that, The elastic film (3) is a composite rubber material, consisting of a rubber base and a reinforcing fiber skeleton.

7. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claims 1-6, characterized in that, The through holes on the perforated panel (1), the columnar channels on the liquid cavity skeleton (2), and the upper end face of the elastic membrane (3) form a uniformly arranged semi-closed liquid cavity. Each semi-closed liquid cavity is connected to the external water body through the through holes. The mass block (4) is located at the center of the bottom of the semi-closed liquid cavity. The lower end face of the elastic film (3), the columnar channel on the air cavity skeleton (5), and the upper end face of the back substrate (6) form an air cavity that is directly opposite to the semi-closed liquid cavity. The skeleton wall between adjacent air cavities is provided with a gap so that the gas between each air cavity is connected.

8. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claim 1, characterized in that, The backing substrate (6) is made of metal.

9. A high-pressure-bearing composite material structure for underwater low-frequency sound absorption according to claims 1-6, characterized in that, The perforated panel (1) and the liquid cavity skeleton (2) are integrally formed or threaded together. The elastic film (3) is connected to the liquid cavity skeleton (2) and the gas cavity skeleton (5) by vulcanization. The liquid cavity skeleton (2) and the gas cavity skeleton (5) are fixedly connected by threads. The gas cavity skeleton (5) and the backing substrate (6) are integrally formed or threaded together.

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