Underwater sound absorption structure, underwater equipment and preparation method of underwater sound absorption structure

Abstract

The invention relates to an underwater sound absorption structure, underwater equipment and a preparation method of the underwater sound absorption structure, and relates to the technical field of shock absorption and noise reduction. The underwater sound absorption structure comprises a honeycomb dot matrix structure, the honeycomb dot matrix structure comprises a honeycomb supporting structure and a plurality of honeycomb type cells arranged in the honeycomb supporting structure, each honeycomb type cell comprises a damping layer component, a resonance unit and a cavity structure are arranged in each damping layer component, and the resonance units are arranged in the cavity structures. And the resonance units are closer to the tops of the honeycomb type cells than the cavity structures. The underwater sound absorption structure can still maintain high sound absorption capacity under high hydrostatic pressure, and a good sound absorption effect can be maintained in low-frequency, intermediate-frequency and high-frequency sound absorption frequency ranges under high pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration reduction and noise reduction, and in particular to an underwater sound absorbing structure, underwater equipment and a method for preparing the underwater sound absorbing structure. Background Art

[0002] Sound waves are currently an effective communication method that can transmit information over long distances underwater, so the vibration and noise reduction of underwater detectors, submersibles and other equipment has always been a major engineering problem. In order to improve the concealment and survivability of underwater equipment, it is often necessary to cover its surface with an acoustic coating (underwater sound-absorbing structure) to isolate the radiation of its own noise and reduce its own acoustic target intensity by sound absorption.

[0003] Since the working environment of some large underwater equipment is in deep water, under the action of hydrostatic pressure, the sound absorption performance of most underwater sound-absorbing structures on it will be greatly reduced or even lose the sound absorption ability, which will have a great impact on the acoustic stealth of the structure. Summary of the invention

[0004] The present invention provides an underwater sound absorbing structure, underwater equipment and a method for preparing the underwater sound absorbing structure, which are used to solve at least one of the above-mentioned technical problems.

[0005] According to a first aspect of the present invention, the present invention provides an underwater sound absorbing structure, comprising a honeycomb lattice structure, wherein the honeycomb lattice structure comprises a honeycomb supporting structure and a plurality of honeycomb cells arranged in the honeycomb supporting structure, each of the honeycomb cells comprises a damping layer component, a resonance unit and a cavity structure are arranged inside the damping layer component, wherein the resonance unit is closer to the top of the honeycomb cell than the cavity structure.

[0006] According to a further optimization of the technical solution of the present invention, the resonance unit is a mass block, the height of the mass block is smaller than the thickness of the damping layer component, and the cross-sectional area of ​​the mass block is smaller than the cross-sectional area of ​​the honeycomb cell.

[0007] According to a further optimization of the technical solution of the present invention, the thickness of the mass block is 1 mm-20 mm.

[0008] In a further optimization of the technical solution of the present invention, the mass block is constructed as one or more of a cylinder, a cuboid, a cube, a sphere, an ellipsoid, a prism and a pyramid.

[0009] According to a further optimization of the technical solution of the present invention, the height of the cavity structure is smaller than the thickness of the damping layer component, and the cross-sectional area of ​​the cavity structure is smaller than the cross-sectional area of ​​the honeycomb cell.

[0010] In a further optimization of the technical solution of the present invention, the cavity structure is constructed as one or more of a circular hole, a polygonal hole, a spherical hole, and an ellipsoidal hole.

[0011] According to a further optimization of the technical solution of the present invention, the thickness of the air layer in the cavity structure is 1 mm-20 mm.

[0012] According to a further optimization of the technical solution of the present invention, the number of the resonance unit and the number of the cavity structure are both one or more.

[0013] According to a further optimization of the technical solution of the present invention, the resonance unit and the cavity structure are both located at the center of the honeycomb cell in the width direction of the honeycomb cell.

[0014] According to a further optimization of the technical solution of the present invention, the damping layer component is made of a polyurethane material having an equivalent isotropic loss factor greater than or equal to 0.5, and the height of the damping layer component is 45 mm-55 mm.

[0015] Further optimization of the technical solution of the present invention, the honeycomb lattice structure also includes a bottom layer structure, which is located at the bottom of each honeycomb cell, and the bottom layer structure is made of a polyurethane material with an equivalent isotropic loss factor greater than or equal to 0.5, and the thickness of the bottom layer structure is 5mm-15mm.

[0016] According to a further optimization of the technical solution of the present invention, the honeycomb support structure comprises a plurality of support members arranged in a honeycomb periodic pattern, and the thickness of the support members is 1 mm to 2 mm.

[0017] In a further optimization of the technical solution of the present invention, the support member is made of a resin-based carbon fiber composite material or a resin-based glass fiber composite material.

[0018] In a further optimization of the technical solution of the present invention, a connecting structure is provided on the support member, and the connecting structure is used to connect adjacent honeycomb cells.

[0019] According to a second aspect of the present invention, the present invention provides an underwater equipment, comprising the above-mentioned underwater sound absorbing structure.

[0020] According to a second aspect of the present invention, the present invention provides a method for preparing an underwater sound absorbing structure, comprising the following steps:

[0021] Honeycomb cells are prepared by introducing a molding process using a vacuum bag method;

[0022] Casting and filling a raw material of a first thickness in each honeycomb cell, and leaving it to stand for a first predetermined time so that the raw material has a certain strength;

[0023] After accurate positioning using a laser rangefinder, the 3D printed or cavity mold shell is placed in each honeycomb cell, and the raw material is poured to a first thickness, and allowed to stand for a second predetermined time so that the raw material has a strength capable of withstanding the resonance unit;

[0024] The resonance unit is added after precise positioning using a laser rangefinder, and the raw materials are poured continuously until the required overall thickness is reached.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] (1) A honeycomb support structure is used to achieve high pressure resistance to meet the requirements of high hydrostatic pressure, and the resonance unit in a single honeycomb cell is closer to the top of the honeycomb cell than the cavity structure, that is, the resonance unit is located above the cavity structure, which can improve the sound absorption performance of the structure; experimental results show that the combination of the mass block and the cavity structure can greatly improve the overall sound absorption performance of the underwater sound absorption structure. Therefore, the underwater sound absorption structure of the present invention can still maintain high sound absorption capacity under high hydrostatic pressure, and maintain good sound absorption effect in the low-frequency, medium-frequency and high-frequency sound absorption frequency ranges under high pressure.

[0027] (2) Through the honeycomb support structure and the mutual reinforcement between the mass block and the cavity structure, the technical problem in the prior art that when the cavity-containing polymer is subjected to water pressure, the local deformation of the polymer is large, resulting in uneven surface and reduced acoustic performance can be solved, while maintaining good pressure-resistant broadband sound absorption performance.

[0028] (3) The combination of mass blocks and cavity structures is used to achieve low-frequency broadband sound absorption performance. By controlling the size, number and distribution of mass blocks and cavity structures, the sound absorption performance of underwater sound absorption structures can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0030] Figure 1 is a schematic diagram of the three-dimensional structure of the underwater sound absorbing structure in an embodiment of the present invention;

[0031] Figure 2 yes Figure 1 Schematic diagram of the three-dimensional structure of the honeycomb cell shown;

[0032] Figure 3 is a schematic structural diagram of a honeycomb support structure in an embodiment of the present invention;

[0033] Figure 4a is a schematic diagram of a honeycomb support structure provided with a communication structure in an embodiment of the present invention, wherein only two adjacent support members are shown;

[0034] Figure 4b A schematic diagram of the structure of multiple honeycomb support structures in an embodiment of the present invention is shown;

[0035] Figure 5a is a stress cloud diagram in which no connecting structure is provided on the supporting member in the embodiment of the present invention;

[0036] Figure 5b is a stress cloud diagram of a connecting structure provided on a support member in an embodiment of the present invention;

[0037] Figure 6a is a displacement cloud diagram at 2000 Hz when the cavity structure is at the bottom in the embodiment of the present invention;

[0038] Figure 6b It is a displacement cloud diagram at 2000 Hz when the cavity structure is at the top in Comparative Example 4 of the present invention;

[0039] Figure 7a is a spectrum of sound absorption coefficients when the hollow cavity structure is at the bottom in an embodiment of the present invention;

[0040] Figure 7b is a spectrum of sound absorption coefficients when the cavity structure is at the top in Comparative Example 4 of the present invention;

[0041] Figure 8a is a spectrum of sound absorption coefficients when two mass blocks are provided in Example 2 of the present invention;

[0042] Figure 8b is a spectrum of sound absorption coefficients when only one mass block is provided in Example 3 of the present invention;

[0043] Figure 9a is a displacement cloud diagram when two mass blocks are provided in Example 2 of the present invention;

[0044] Figure 9b is a displacement cloud diagram when two mass blocks are provided in Example 3 of the present invention;

[0045] Reference numerals:

[0046] 100, honeycomb lattice structure; 110, honeycomb support structure; 120, honeycomb cell; 130, bottom structure; 140, outer shell;

[0047] 121. resonance unit; 122. cavity structure;

[0048] 111. Support member; 112. Hexagonal hole; 113. Connecting structure. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings.

[0050] The present invention provides an underwater sound absorbing structure. More specifically, the underwater sound absorbing structure of the present invention is a honeycomb-enhanced pressure-resistant resonance underwater sound absorbing structure, which can withstand the high hydrostatic pressure of deep-sea operations and maintain structural stability under high hydrostatic pressure; and enhance cavity resonance through local resonance to achieve the purpose of pressure resistance and broadband sound absorption. The underwater sound absorbing structure of the present invention can solve the technical problem in the prior art that the structure of the cavity-containing polymer undergoes large deformation under high hydrostatic pressure, resulting in uneven surface and a significant decrease in the acoustic performance of the structure, while maintaining good low-frequency broadband sound absorption performance.

[0051] like Figure 1 and Figure 2 As shown, the underwater sound absorbing structure of the present invention includes a honeycomb lattice structure 100, which includes a honeycomb support structure 110 and a plurality of honeycomb cells 120 arranged in the honeycomb support structure 110, and the plurality of honeycomb cells 120 are distributed in an array to form a honeycomb structure with a honeycomb periodic arrangement.

[0052] Each honeycomb cell 120 includes a damping layer component, which may be a hexagonal column structure, for example, to form a honeycomb structure. The damping layer component structure is a uniform hexagonal column structure, which can meet the requirements of simple structure and easy processing.

[0053] The damping layer component is provided with a resonance unit 121 and a cavity structure 122, wherein the resonance unit 121 is closer to the top of the honeycomb cell 120 than the cavity structure 122. The "top" of the honeycomb cell 120 refers to the position when the underwater sound absorbing structure is placed underwater for operation, such as Figure 2 As shown, the "top" of the honeycomb cell 120 is the left side thereof.

[0054] The resonance unit 121 in the present invention is closer to the top of the honeycomb cell 120 than the cavity structure 122, that is, the resonance unit 121 is located above the cavity structure 122 (eg Figure 2 As shown, the resonance unit 121 is located above the cavity structure 122 in the X direction), thereby achieving the purpose of improving the sound absorption performance.

[0055] The experimental results show that the overall sound absorption performance of the underwater sound absorption structure can be greatly improved by combining the resonance unit 121 with the cavity structure 122. Furthermore, the honeycomb support structure 110 and the mutual reinforcement of the resonance unit 121 and the cavity structure 122 can solve the technical problem in the prior art that the surface of the porous polymer is uneven and the acoustic performance is reduced due to the large local deformation of the polymer when it is subjected to water pressure, while maintaining good pressure-resistant broadband sound absorption performance.

[0056] Specifically, the resonance unit 121 is a mass block, and the mass block can be, for example, a local resonance type phononic crystal. In the low frequency range, the sound absorption mechanism of the local resonance type phononic crystal is mainly the shear loss caused by the resonance of the local resonance body under the excitation of the sound wave; when the frequency is higher, the main sound absorption mechanism of the local resonance type phononic crystal is the scattering effect of the local resonance body on the sound waves in the solid. The local resonance type phononic crystal has a wide sound absorption bandwidth. By using the mass block as the resonance unit 121, the cavity structure 122 can be driven to vibrate together, thereby achieving the purpose of sound absorption. Therefore, the present invention can achieve low-frequency broadband sound absorption performance by combining the mass block and the cavity structure 122.

[0057] Therefore, the underwater sound absorbing structure of the present invention achieves the purpose of high pressure resistance by adopting a honeycomb support structure 110, and can withstand the high hydrostatic pressure of deep-sea operations and maintain structural stability. The invention is based on the idea of ​​enhancing cavity resonance by local resonance type phononic crystals, and forms an underwater sound absorbing structure with a single honeycomb cell 120 as a period, which can achieve the purpose of pressure resistance and broadband sound absorption. The underwater sound absorbing structure of the present invention can solve the technical problem in the prior art that the structure of the cavity-containing polymer undergoes large deformation under high hydrostatic pressure, resulting in uneven surface and a significant decrease in the acoustic performance of the structure, while maintaining good low-frequency broadband sound absorption performance.

[0058] The height of the mass block (i.e. Figure 2 The dimension in the X direction shown in FIG. 1 is smaller than the damping layer component (i.e. Figure 2 The thickness of the mass block is smaller than the cross-sectional area of ​​the honeycomb cell (the dimension in the Y direction shown in the figure), and the cross-sectional area of ​​the mass block is smaller than the cross-sectional area of ​​the honeycomb cell, thereby ensuring that the mass block can be completely embedded in the honeycomb cell (damping layer component).

[0059] The thickness of the mass block is 1mm-20mm. The mass block can be one or more, such as Figure 2 , an example is shown in which there is one mass block (resonance unit 121). When there are multiple mass blocks (resonance units 121), the multiple mass blocks can be arranged along the length direction of the honeycomb cell 120 (for example, Figure 2 X direction as shown) and / or width direction (for example, it can be Figure 2 The two electrodes are arranged at intervals in the Y direction as shown.

[0060] When there are multiple mass blocks (resonance units 121 ), one of the mass blocks may be disposed above the cavity structure 122 , or all of the mass blocks may be disposed above the cavity structure 122 .

[0061] The mass block is constructed as a structure of regular shape, for example, it can be one of a cylinder, a cuboid, a cube, a sphere, an ellipsoid, a prism and a pyramid. The axial direction of the mass block is consistent with the length direction of the honeycomb cell 120, that is, the mass block extends along the length direction of the honeycomb cell 120. Figure 2 As shown, an example of a mass block having a cylindrical structure is shown. It can be understood that when there are multiple mass blocks, the structures of the multiple mass blocks can be the same or different, so the mass blocks can be multiple of a cylinder, a cuboid, a cube, a sphere, an ellipsoid, a prism and a pyramid, for example, some of the mass blocks are cylinders, and other mass blocks are cuboids, etc.

[0062] The height of the cavity structure 122 (i.e. Figure 2 The dimension in the X direction shown in FIG. 1 is smaller than the damping layer component (i.e. Figure 2 The cross-sectional area of ​​the cavity structure 122 is smaller than the cross-sectional area of ​​the honeycomb cell. Under the excitation of underwater sound waves, the damping layer component on the upper side of the cavity structure 122 will vibrate like a drum; at the same time, due to the mismatch between the damping medium and the air acoustic impedance in the cavity structure 122, the sound waves will be scattered on the surface of the cavity structure 122; in addition, when the sound waves are incident on the surface of the cavity structure 122, waveform conversion will occur, thereby achieving the purpose of sound absorption.

[0063] The cavity structure 122 may be one or more, such as Figure 2 As shown, an example in which the cavity structure 122 is one is shown. When there are multiple cavity structures 122, the multiple cavity structures 122 can be arranged along the length direction of the honeycomb cell 120 (for example, Figure 2 X direction as shown) and / or width direction (for example, it can be Figure 2 The two electrodes are arranged at intervals in the Y direction as shown.

[0064] The cavity structure 122 is essentially a hole with both ends closed formed in the damping layer component, and its axial direction is consistent with the length direction of the honeycomb cell 120, that is, the cavity structure 122 extends along the length direction of the honeycomb cell 120. The above-mentioned hole with both ends closed can be constructed as one of a circular hole, a polygonal hole, a spherical hole, and an ellipsoidal hole. Figure 2 As shown, an example in which the cavity structure 122 is a cylindrical structure is shown. It can be understood that when there are multiple cavity structures 122, the structures of the multiple cavity structures 122 can be the same or different, so the cavity structure 122 can be a variety of circular holes, polygonal holes, spherical holes, and ellipsoidal holes. For example, some of the cavity structures 122 are circular holes formed in the damping layer component, and other cavity structures 122 are polygonal holes formed in the damping layer component.

[0065] The polygonal holes include triangular holes, quadrilateral holes, pentagonal holes or holes with more sides.

[0066] The medium in the cavity structure 122 is air, so the thickness of the air layer in the cavity structure 122 may be 1 mm-20 mm. It can be understood that the diameter of the hole forming the cavity structure 122 may be 1 mm-20 mm.

[0067] The mass block (resonance unit 121) and the cavity structure 122 are arranged in the width direction of the honeycomb cell 120 (for example, Figure 2 In the Y direction shown in the figure, they are all located at the central position of the honeycomb cell 120.

[0068] The parameters of the mass block and the cavity structure 122 in the honeycomb cell 120 are highly designable. For example, the size, quantity and distribution of the mass block and the cavity structure 122 can be controlled to adjust the sound absorption performance of the material and meet the integrated requirements of pressure resistance and low-frequency broadband sound absorption, thereby effectively improving the sound absorption performance of the underwater sound absorption structure.

[0069] The damping layer component is made of a viscoelastic polyurethane material, for example, the damping layer component is made of a polyurethane material having an equivalent isotropic loss factor greater than or equal to 0.5. As a non-primary load-bearing material, the material of the damping layer component has excellent softness and deformation capacity, is conducive to absorbing low-frequency sound waves, and achieves a good sound absorption effect. In addition, the raw materials for preparing the damping layer component are easily available and easy to prepare.

[0070] The height of the damping layer component is 45mm-55mm, preferably, the height of the damping layer component is 50mm. Figure 2 Dimensions in the X direction are shown.

[0071] like Figure 1 As shown, the honeycomb lattice structure 100 further includes a bottom layer structure 130, and the bottom layer structure 130 is located at the bottom of each honeycomb cell 120. Figure 2 As shown, the underlying structure 130 may be a structure that conforms to the shape of each honeycomb cell 120 , such as a hexagonal prism structure.

[0072] The bottom structure 130 is made of a polyurethane material having an equivalent isotropic loss factor greater than or equal to 0.5, and the height of the bottom structure 130 is 5 mm to 15 mm. Figure 2 Dimensions in the X direction are shown.

[0073] The honeycomb support structure 110 includes a plurality of support members 111 arranged in a honeycomb periodic pattern. Figure 4bAs shown, the support members 111 surround each other to form a hexagonal hole 112, and each honeycomb cell 120 is respectively arranged in a corresponding hexagonal hole 112, that is, a honeycomb sound absorbing structure is formed. The cross-sectional side length of the hexagonal hole 112 can be 11mm-22mm.

[0074] The support member 111 is made of high-strength fiber material, for example, can be made of resin-based carbon fiber composite material or resin-based glass fiber composite material. The honeycomb support structure 110 formed therefrom has excellent bearing capacity and can effectively improve the bearing capacity of the underwater sound absorbing structure in a high hydrostatic pressure environment.

[0075] The thickness of the support member 111 may be 1 mm to 2 mm. Since the support member 111 is made of a resin-based carbon fiber composite material or a resin-based glass fiber composite material, its thickness may be set relatively small, thereby achieving the requirement of lightweight.

[0076] like Figure 3 and Figure 4a As shown, in an exemplary embodiment, a connecting structure 113 is provided on the support member 111, and the connecting structure 113 is used to connect the cavity structures 122 of adjacent honeycomb cells 120 to form a connecting domain. The connecting structure 113 can be formed by rotary cutting or the like, which can connect the honeycomb cells 120 to each other, and sound waves can be transmitted and consumed in the honeycomb cells 120 arranged in a honeycomb periodic pattern, thereby further improving the sound absorption performance of the underwater sound absorption structure. Figure 3 As shown, each support member 111 forming the side wall of the hexagonal hole 112 is provided with a connecting structure 113. The connecting structure 113 may be a connecting hole, for example.

[0077] like Figure 5a As shown, a stress cloud diagram is shown when no connecting structure 113 is provided on the support member 111 (only two adjacent support members 111 are shown). Figure 5a As shown, a connecting structure 113 is provided on the support member 111 to form a stress cloud diagram of a connected domain (only two adjacent support members 111 are shown), and the stress cloud diagrams of the two are basically consistent.

[0078] By changing the geometric dimensions of the support 111 and the geometric dimensions of the cavity structure 122, the mechanical properties and acoustic properties of the underwater sound absorbing structure can be conveniently changed, so that the underwater sound absorbing structure has strong performance designability, thereby meeting the multifunctional design requirements of load-bearing-sound absorption-lightweight.

[0079] The underwater sound absorbing structure of the present invention can solve the problem that the existing cavity-type sound absorbing structure deforms under high hydrostatic pressure, and causes the acoustic performance to decline or even fail. By using high-strength fiber materials to form a honeycomb support structure 110 as a load-bearing component, and using the damping layer component containing a mass block (resonance unit 121) and a cavity structure 122 as a sound absorbing component, it can meet the following requirements: broadband sound absorption in a certain frequency band; and the requirement of maintaining sound absorption performance without decline under high hydrostatic pressure. Specifically, the underwater sound absorbing structure of the present invention has excellent hydrostatic pressure resistance and good sound absorption performance, and can effectively ensure broadband sound absorption and sound insulation in the frequency band of 1000 to 10000 Hz under a hydrostatic pressure of 3 MPa. Therefore, the underwater sound absorbing structure of the present invention can be used to manufacture underwater equipment, such as the shell and wall of detectors, submersibles, etc., to meet the needs of underwater noise reduction. The underwater sound absorption of the present invention has a wide range of engineering application prospects, and it can provide a new solution for underwater shock reduction and noise reduction of engineering structures and the multifunctional design of lightweight sandwich structures.

[0080] In addition, the underwater sound absorbing structure of the present invention can also meet the requirements of: lightweight design; simple structure and easy processing; and multifunctional design requirements of load-bearing, sound absorption and lightweight.

[0081] The performance of the underwater sound absorbing structure of the present invention will be described in detail below through specific experimental embodiments and comparative examples as well as simulation embodiments.

[0082] Example 1

[0083] In this embodiment 1, the underwater sound absorbing structure includes a honeycomb lattice structure 100, which includes a honeycomb support structure 110, a plurality of honeycomb cells 120 arranged in the honeycomb support structure 110, and an underlying structure 130 arranged at the bottom of each honeycomb cell 120. Each honeycomb cell 120 includes a damping layer component, and a resonance unit 121 and a cavity structure 122 are arranged inside the damping layer component, wherein the resonance unit 121 is closer to the top of the honeycomb cell 120 than the cavity structure 122. The "top" of the honeycomb cell 120 refers to the orientation when the underwater sound absorbing structure is placed underwater for operation. The resonance unit 121 is a local resonance type phononic crystal.

[0084] The honeycomb support structure 110 includes a plurality of support members 111 arranged in a honeycomb periodic pattern. The parameters of each support member 111 are as follows:

[0085] The support member 111 is made of a resin-based carbon fiber composite material with a density of 1150 kg / m 3 , Young's modulus is 40GPa, Poisson's ratio is 0.1, and equivalent isotropic loss factor is 0;

[0086] The thickness of the support member 111 is 1 mm;

[0087] The diameter of the inscribed circle of the hexagonal hole 112 surrounded by the support member 111 is 18 mm;

[0088] The parameters of the damping layer component are as follows:

[0089] The damping layer component is made of polyurethane with a density of 1043kg / m 3 , Young's modulus is 200MPa, Poisson's ratio is 0.49, and equivalent isotropic loss factor is 0.6;

[0090] The height of the damping layer member is 50 mm.

[0091] The parameters of the mass block (resonance unit 121) and the cavity structure 122 in the damping layer component are as follows:

[0092] The number of mass blocks (resonance units 121) is one. The mass block (resonance unit 121) has a rectangular parallelepiped structure. The height of the mass block (resonance unit 121) is 15 mm, and the length and width of the mass block (resonance unit 121) are both 9 mm. The mass block (resonance unit 121) is arranged in a horizontal direction (such as Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the axial direction of the honeycomb lattice structure 100 and the upper surface of the damping layer component is 2 mm.

[0093] The number of the cavity structure 122 is one. The cavity structure 122 is a rectangular parallelepiped structure. The height of the cavity structure 122 is 12 mm, and the length and width of the cavity structure 122 are both 7.5 mm. Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The honeycomb lattice structure 100 shown is located at the bottom of the damping layer component in the axial direction (ie, the distance from the bottom of the damping layer component is 0 mm).

[0094] The density of the air layer in the cavity structure 122 is 1.29 kg / m 3 .

[0095] The parameters of the underlying structure 130 are as follows:

[0096] The substructure 130 is made of polyurethane with a density of 1072 kg / m 3 , Young's modulus is 80MPa, Poisson's ratio is 0.485, and the equivalent isotropic loss factor is 0.6.

[0097] The underwater sound absorbing structure of Example 1 of the present invention has a compressive strength of up to 520.6 MPa due to the honeycomb support structure 110 (the compressive strength of the underwater sound absorbing structure without the honeycomb support structure is only 57.9 MPa).

[0098] The sound absorption performance of the underwater sound absorption structure of Example 1 of the present invention is obtained by performing experiments on the test samples of the underwater sound test. Specifically, the underwater sound absorption structure of Example 1 of the present invention has an average sound absorption coefficient of 0.73 in the frequency range of 500Hz to 10000Hz without water pressure; an average sound absorption coefficient of 0.75 in the frequency range of 500Hz to 10000Hz under a pressure of 1MPa; an average sound absorption coefficient of 0.74 in the frequency range of 500Hz to 10000Hz under a pressure of 2MPa; and an average sound absorption coefficient of 0.7 in the frequency range of 500Hz to 10000Hz under a pressure of 3MPa. Therefore, it can be seen that the underwater sound absorption structure of Example 1 of the present invention can maintain a small decrease in sound absorption performance under high hydrostatic pressure, and realize broadband sound absorption within a certain frequency band.

[0099] In addition, using the above structure and materials, in order to further illustrate the influence of the structure size on the acoustic performance of the underwater sound absorbing structure of the present invention, the following comparative examples are provided.

[0100] Comparative Example 1

[0101] In Comparative Example 1, the underwater sound absorbing structure of the present invention is not provided with a honeycomb supporting structure 110 , that is, the underwater sound absorbing structure of Comparative Example 1 only includes honeycomb cells 120 forming a sound absorbing layer and a bottom layer structure 130 arranged at the bottom of each honeycomb cell 120 .

[0102] Similar to the above-mentioned embodiment 1, the honeycomb cell 120 includes a damping layer component, which is made of high-damping polymer polyurethane. The interior of the damping layer component is provided with a cavity structure 122 and a mass block (resonance unit 121). The mass block (resonance unit 121) is located above the cavity structure 122, and the cavity structure 122 and the mass block are evenly distributed in the honeycomb cell 120 in the horizontal direction.

[0103] The parameters of the damping layer component are as follows:

[0104] The damping layer component is made of polyurethane, with an equivalent isotropic loss factor of 0.6 and a Young's modulus of 3 MPa. The height of the damping layer component is 50 mm and the diameter is 118 mm.

[0105] The number of mass blocks (resonance units 121) is one. The mass block (resonance unit 121) adopts a cylindrical structure. The height of the mass block (resonance unit 121) is 10 mm and the diameter is 50 mm. The mass block (resonance unit 121) is horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the upper surface of the damping layer component is 10 mm.

[0106] The number of the cavity structure 122 is one. The cavity structure 122 is a cylindrical structure. The height of the cavity structure 122 is 10 mm, and the diameter of the cavity structure 122 is 50 mm. The cavity structure 122 is disposed horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the bottom of the damping layer component is 10 mm.

[0107] The parameters of the underlying structure 130 are as follows:

[0108] The substructure 130 is made of polyurethane, and has an equivalent isotropic loss factor of 0.6 and a Young's modulus of 70 MPa.

[0109] Other unspecified parameters in Comparative Example 1 may be kept consistent with the parameters in Example 1.

[0110] The sound absorption performance of the underwater sound absorption structure of comparative example 1 of the present invention is obtained by conducting experiments on the test samples of the underwater sound test. Specifically, the underwater sound absorption structure of comparative example 1 of the present invention has an average sound absorption coefficient of 0.81 in the frequency range of 500Hz to 10000Hz without water pressure; an average sound absorption coefficient of 0.69 in the frequency range of 500Hz to 10000Hz under a pressure of 1MPa; an average sound absorption coefficient of 0.65 in the frequency range of 500Hz to 10000Hz under a pressure of 2MPa; and an average sound absorption coefficient of 0.6 in the frequency range of 500Hz to 10000Hz under a pressure of 3MPa.

[0111] Therefore, it can be seen that although the underwater sound absorbing structure of Comparative Example 1 of the present invention maintains good sound absorption performance in the absence of water pressure, it cannot maintain its sound absorption performance under high hydrostatic pressure, that is, the underwater sound absorbing structure of Comparative Example 1 of the present invention maintains a significant decrease in sound absorption performance under high hydrostatic pressure.

[0112] Comparative Example 2

[0113] In Comparative Example 2, the underwater sound absorbing structure of the present invention is not provided with the honeycomb supporting structure 110 , that is, the underwater sound absorbing structure of Comparative Example 2 only includes the honeycomb cells 120 forming the sound absorbing layer and the bottom layer structure 130 arranged at the bottom of each honeycomb cell 120 .

[0114] The honeycomb cell 120 includes a damping layer member. However, in Comparative Example 2, the honeycomb cell 120 is only provided with a mass block (resonance unit 121 ) but not with a cavity structure 122 .

[0115] The parameters of the damping layer component are as follows:

[0116] The damping layer component is made of polyurethane, with an equivalent isotropic loss factor of 0.6 and a Young's modulus of 200 MPa. The height of the damping layer component is 50 mm and the diameter is 118 mm.

[0117] The number of mass blocks (resonance units 121) is two. Both mass blocks (resonance units 121) are cylindrical structures. The height of both mass blocks (resonance units 121) is 10 mm and the diameter is 50 mm. One of the mass blocks (resonance units 121) is horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the figure and the upper surface of the damping layer component is 10 mm. The other mass block (resonance unit 121) is located in the horizontal direction (such as Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the bottom of the damping layer component is 10 mm.

[0118] The parameters of the underlying structure 130 are as follows:

[0119] The substructure 130 is made of polyurethane, and has an equivalent isotropic loss factor of 0.6 and a Young's modulus of 80 MPa.

[0120] Other unspecified parameters in Comparative Example 2 may be kept consistent with the parameters in Example 1.

[0121] The sound absorption performance of the underwater sound absorption structure of comparative example 2 of the present invention is obtained by performing experiments on the test samples of the underwater sound test. Specifically, the underwater sound absorption structure of comparative example 2 of the present invention has an average sound absorption coefficient of 0.78 in the frequency range of 500Hz to 10000Hz without water pressure; an average sound absorption coefficient of 0.55 in the frequency range of 500Hz to 10000Hz under a pressure of 1MPa; an average sound absorption coefficient of 0.47 in the frequency range of 500Hz to 10000Hz under a pressure of 2MPa; and an average sound absorption coefficient of 0.45 in the frequency range of 500Hz to 10000Hz under a pressure of 3MPa.

[0122] Therefore, it can be seen that although the underwater sound absorbing structure of Comparative Example 2 of the present invention maintains good sound absorption performance in the absence of water pressure, its sound absorption performance is greatly reduced under high hydrostatic pressure, that is, the underwater sound absorbing structure of Comparative Example 2 of the present invention maintains a large decrease in sound absorption performance under high hydrostatic pressure.

[0123] In addition, by comparing Comparative Example 1 and Comparative Example 2, it can be seen that under no water pressure and various pressures, since Comparative Example 1 is provided with a cavity structure 122, while Comparative Example 2 is not provided with a cavity structure 122, the sound absorption performance of Comparative Example 1 is significantly better than the sound absorption structure of Comparative Example 2.

[0124] Comparative Example 3

[0125] In Comparative Example 3, the underwater sound absorbing structure of the present invention is not provided with a honeycomb supporting structure 110 , that is, the underwater sound absorbing structure of Comparative Example 3 only includes honeycomb cells 120 forming a sound absorbing layer and a bottom layer structure 130 arranged at the bottom of each honeycomb cell 120 .

[0126] The honeycomb cell 120 includes a damping layer member. However, in Comparative Example 3, the honeycomb cell 120 is only provided with a cavity structure 122, but no mass block (resonance unit 121) is provided.

[0127] The parameters of the damping layer component are as follows:

[0128] The damping layer component is made of polyurethane, with an equivalent isotropic loss factor of 0.6 and a Young's modulus of 3 MPa. The height of the damping layer component is 50 mm and the diameter is 118 mm.

[0129] The number of cavity structures 122 is two. Both cavity structures 122 are cylindrical structures. The height of both cavity structures 122 is 10 mm, and the diameter of both cavity structures 122 is 50 mm. One of the cavity structures 122 is horizontal (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1The distance between the honeycomb lattice structure 100 in the axial direction and the upper surface of the damping layer component is 10 mm. Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the bottom of the damping layer component is 10 mm.

[0130] The parameters of the underlying structure 130 are as follows:

[0131] The substructure 130 is made of polyurethane, and has an equivalent isotropic loss factor of 0.6 and a Young's modulus of 70 MPa.

[0132] Other unspecified parameters in Comparative Example 3 may be kept consistent with the parameters in Example 1.

[0133] The sound absorption performance of the underwater sound absorption structure of Comparative Example 3 of the present invention is obtained by performing experiments on the test samples of the underwater sound test. Specifically, the underwater sound absorption structure of Comparative Example 3 of the present invention has an average sound absorption coefficient of 0.69 in the frequency range of 500Hz to 10000Hz without water pressure; an average sound absorption coefficient of 0.58 in the frequency range of 500Hz to 10000Hz under a pressure of 1MPa; an average sound absorption coefficient of 0.55 in the frequency range of 500Hz to 10000Hz under a pressure of 2MPa; and an average sound absorption coefficient of 0.52 in the frequency range of 500Hz to 10000Hz under a pressure of 3MPa.

[0134] Therefore, it can be seen that although the underwater sound absorbing structure of Comparative Example 3 of the present invention maintains good sound absorption performance in the absence of water pressure, its sound absorption performance is greatly reduced under high hydrostatic pressure, that is, the underwater sound absorbing structure of Comparative Example 3 of the present invention maintains a large decrease in sound absorption performance under high hydrostatic pressure.

[0135] In addition, by comparing Comparative Example 1 and Comparative Example 3, it can be seen that under no water pressure and various pressures, since Comparative Example 1 is provided with a mass block (resonance unit 121) while Comparative Example 2 is not provided with a mass block (resonance unit 121), the sound absorption performance of Comparative Example 1 is significantly better than the sound absorption structure of Comparative Example 3.

[0136] The average sound absorption coefficients of the underwater sound absorbing structure of Example 1 of the present invention and the underwater sound absorbing structures of various comparative examples at different pressures are shown in Table 1.

[0137] Table 1 List of average sound absorption coefficients in the frequency range of 500Hz to 10000Hz

[0138]

[0139] According to the above Table 1, it can be intuitively seen that the sound absorption performance of the underwater sound absorbing structure in Example 1 of the present invention under high hydrostatic pressure is basically maintained near the sound absorption performance under no water pressure, but the sound absorption performance of the underwater sound absorbing structures of Comparative Examples 1, 2 and 3 of the present invention under high hydrostatic pressure is significantly reduced.

[0140] Therefore, it can be seen that the combination of the mass block (resonance unit 121) and the cavity structure 122 in the underwater sound absorption structure of the present invention can improve the sound absorption performance in a wide frequency range. The sound absorption performance of the solution combining the mass block (resonance unit 121) and the cavity structure 122 is greatly improved compared with the comparative example 2 in which only the mass block (resonance unit 121) is set and the comparative example 3 in which only the cavity structure 122 is set.

[0141] In addition, the present invention also provides the following Results of simulation calculations of underwater sound-absorbing structures.

[0142] Comparative Example 4

[0143] In Comparative Example 4, the underwater sound absorbing structure includes a honeycomb supporting structure 110 , honeycomb cells 120 forming a sound absorbing layer, and a bottom layer structure 130 disposed at the bottom of each honeycomb cell 120 .

[0144] The honeycomb type cell 120 includes a damping layer member made of high damping polymer polyurethane, and a cavity structure 122 and a mass block (resonance unit 121) are provided inside the damping layer member.

[0145] Different from the above-mentioned embodiment 1, in comparative example 4, the mass block (resonance unit 121) is arranged below the cavity structure 122, that is, the cavity structure 122 is located above and the resonance unit 121 is located below.

[0146] In addition, the cavity structure 122 and the mass block are evenly distributed in the honeycomb cell 120 in the horizontal direction.

[0147] The number of mass blocks (resonance units 121) is one. The mass block (resonance unit 121) adopts a cylindrical structure. The height of the mass block (resonance unit 121) is 10 mm and the diameter is 50 mm. The mass block (resonance unit 121) is horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the bottom of the damping layer component is 10 mm.

[0148] The number of the cavity structure 122 is one. The cavity structure 122 is a cylindrical structure. The height of the cavity structure 122 is 10 mm, and the diameter of the cavity structure 122 is 50 mm. The cavity structure 122 is disposed horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the upper surface of the damping layer component is 10 mm.

[0149] Other unspecified parameters in Comparative Example 4 may be kept consistent with the parameters of Example 1 (or Comparative Examples 1-3).

[0150] The sound absorption performance of the underwater sound absorption structure of Comparative Example 4 is calculated by the simulation model. Specifically, the sound absorption coefficient in the frequency range of 1000 Hz to 10000 Hz obtained by calculation is shown in Table 1 below.

[0151] Table 1 List of sound absorption coefficients in the frequency range of 500Hz to 10000Hz in Comparative Example 4

[0152]

[0153]

[0154] According to Table 1, the underwater sound absorption structure of Comparative Example 4 (the mass block is located below the cavity structure 122) has an average sound absorption coefficient of 0.782 in the frequency range of 1000 Hz to 10000 Hz.

[0155] In summary, the combination of the mass block and the cavity structure 122 in the underwater sound absorbing structure of the present invention can improve the sound absorption performance in a wide frequency range, and the sound absorption performance when the mass block is located above the cavity structure 122 is better than the sound absorption performance when the mass block is located below the cavity structure 122. It can be seen that reasonable control of the distribution of the mass block and the cavity structure 122 can greatly improve the sound absorption performance of the underwater sound absorbing structure.

[0156] Similarly, simulation model calculations are performed on other embodiments of the present invention, as described in detail below. The average sound absorption coefficient of the underwater sound absorbing structure (for example, using the parameters in Example 1) in which the mass block is arranged above the cavity structure 122 is 0.87 after simulation calculation. Therefore, it can be seen that in Comparative Example 4, the sound absorption performance of the underwater sound absorbing structure is greatly reduced by placing the mass block below the cavity structure 122.

[0157] In addition, if Figure 6b The displacement cloud diagram at 2000 Hz is shown when the cavity structure 122 is above the mass block in Comparative Example 4. Figure 7bThe sound absorption coefficient spectrum of the cavity structure in Comparative Example 4 is shown above the mass block; Figure 6a The displacement cloud diagram at 2000 Hz is shown when the cavity structure 122 is below the mass block. Figure 7a It is a spectrum of sound absorption coefficient when the cavity structure is below the mass block. It can be seen that when the mass block is located below the cavity structure 122, the high-frequency sound absorption performance is much lower than the low-frequency sound absorption performance.

[0158] Example 2

[0159] exist Example 2 In the embodiment, the underwater sound absorbing structure includes honeycomb cells 120 forming a sound absorbing layer and a bottom layer structure 130 arranged at the bottom of each honeycomb cell 120 .

[0160] The honeycomb cell 120 includes a damping layer member made of high damping polymer polyurethane, and a cavity structure 122 and a mass block (resonance unit 121 ) are disposed inside the damping layer member. The mass block (resonance unit 121 ) is located above the cavity structure 122 .

[0161] In addition, the cavity structure 122 and the mass block are evenly distributed in the honeycomb cell 120 in the horizontal direction.

[0162] The number of mass blocks (resonance units 121) is two. The mass blocks (resonance units 121) are cylindrical structures. One of the mass blocks (resonance units 121) has a height of 10 mm and a diameter of 20 mm. The mass block (resonance unit 121) is 10 mm in the horizontal direction (such as Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the figure and the upper surface of the damping layer component is 8 mm; the height of another mass block (resonance unit 121) is 10 mm and the diameter is 30 mm. Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the upper surface of the damping layer component is 23 mm.

[0163] The number of the cavity structure 122 is one. The cavity structure 122 is a cylindrical structure. The height of the cavity structure 122 is 10 mm, and the diameter of the cavity structure 122 is 50 mm. The cavity structure 122 is disposed horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1The distance between the honeycomb lattice structure 100 shown in the axial direction and the upper surface of the damping layer component is 2 mm.

[0164] Example 2 Other unspecified parameters may be consistent with those of Example 1 (or Comparative Examples 1-3).

[0165] The present invention Example 2 The sound absorption performance of the underwater sound absorption structure of the present invention is calculated by the simulation model. Example 2 The sound absorption performance of the underwater sound absorption structure is calculated by the simulation model. Specifically, the sound absorption coefficient in the frequency range of 500 Hz to 10000 Hz obtained by calculation is shown in Table 2 below.

[0166] Table 2 Example 2 List of sound absorption coefficients in the frequency range of 500Hz to 10000Hz

[0167]

[0168]

[0169] The underwater sound absorbing structure of Example 2 of the present invention has an average sound absorption coefficient of 0.812 in the frequency range of 500 Hz to 10000 Hz. Figure 8a and Figure 9a As shown, the sound absorption coefficient spectrum and displacement cloud diagram when two mass blocks are set in Example 2 are respectively shown.

[0170] Example 3

[0171] In the third embodiment, the underwater sound absorbing structure includes honeycomb cells 120 forming a sound absorbing layer and a bottom layer structure 130 disposed at the bottom of each honeycomb cell 120 .

[0172] The honeycomb cell 120 includes a damping layer member made of high damping polymer polyurethane, and a cavity structure 122 and a mass block (resonance unit 121 ) are disposed inside the damping layer member. The mass block (resonance unit 121 ) is located above the cavity structure 122 .

[0173] In addition, the cavity structure 122 and the mass block are evenly distributed in the honeycomb cell 120 in the horizontal direction.

[0174] The number of mass blocks (resonance units 121) is 1. The mass block (resonance unit 121) has a cylindrical structure. The height of the mass block (resonance unit 121) is 10 mm and the diameter is 20 mm. The mass block (resonance unit 121) is 10 mm in the horizontal direction (such as Figure 1The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the upper surface of the damping layer component is 8 mm.

[0175] The number of the cavity structure 122 is one. The cavity structure 122 is a cylindrical structure. The height of the cavity structure 122 is 10 mm, and the diameter of the cavity structure 122 is 50 mm. The cavity structure 122 is disposed horizontally (eg Figure 1 The honeycomb lattice structure 100 shown in the figure is located at the center of each honeycomb cell in the radial direction and in the vertical direction (such as Figure 1 The distance between the honeycomb lattice structure 100 shown in the axial direction and the upper surface of the damping layer component is 2 mm.

[0176] Other unspecified parameters in Example 3 may be consistent with the parameters of Example 1 (or Comparative Examples 1-3).

[0177] The sound absorption performance of the underwater sound absorption structure of Example 3 of the present invention is calculated by the simulation model. Specifically, the sound absorption performance of the underwater sound absorption structure of Example 3 of the present invention is calculated by the simulation model. Specifically, the sound absorption coefficient in the frequency range of 500 Hz to 10000 Hz obtained by calculation is shown in Table 3 below.

[0178] Table 3 List of sound absorption coefficients in the frequency range of 500 Hz to 10000 Hz in Example 3

[0179]

[0180]

[0181] The underwater sound absorbing structure of Example 3 of the present invention has an average sound absorption coefficient of 0.80 in the frequency range of 500 Hz to 10000 Hz. Figure 8b and Figure 9b As shown, the sound absorption coefficient spectrum and displacement cloud diagram when two mass blocks are set in Example 3 are respectively shown. Therefore, it can be seen that the combination of the mass block and the cavity structure 122 in the underwater sound absorption structure of the present invention can improve the sound absorption performance in a wide frequency range, and the sound absorption performance of the structure can be further improved by changing the number of mass blocks or cavity structures 122.

[0182] According to the above embodiments and comparative examples, the underwater sound absorbing structure of the present invention can achieve the following five technical effects:

[0183] 1. The underwater sound absorbing structure of the present invention (as described in Example 1) still maintains broadband sound absorption. In the frequency range of 500 to 10,000 Hz, the average sound absorption coefficient reaches above 0.7, which can meet the requirements of broadband sound absorption within a certain frequency band.

[0184] 2. The sound absorption performance of the underwater sound absorbing structure of the present invention (as described in Example 1) under the hydrostatic pressure within a water depth of 300 m is basically maintained unchanged. It can be considered that the acoustic performance of the underwater sound absorbing structure is not affected under high hydrostatic pressure, and can meet the requirement of maintaining the sound absorption performance without degradation under high hydrostatic pressure;

[0185] 3. The underwater sound absorbing structure of the present invention has a honeycomb support structure 110 made of a resin-based carbon fiber composite material, and a damping layer component of the honeycomb cell 120 is made of polyurethane. A cavity structure 122 is provided in the damping layer component. Compared with the local resonance type phononic crystal widely studied at present, the density of the overall structure is reduced, and in a specific implementation, the total thickness of the structure is only 50 mm, which can meet the requirements of lightweight design;

[0186] 4. The damping layer component, the resonance unit 121, the cavity structure 122 and the support member 111 of the underwater sound absorbing structure of the present invention are all regular-shaped structures, so the structure is simple and easy to process;

[0187] 5. The underwater sound absorbing structure of the present invention can conveniently change the mechanical properties and acoustic properties of the underwater sound absorbing structure by changing the geometric dimensions of the supporting member 111 and other rods, the outer shell 140, and the geometric dimensions of the mass block and the cavity structure 122, so that the underwater sound absorbing structure has strong performance designability and meets the multifunctional design requirements of load-bearing-sound absorption-lightweight.

[0188] Therefore, the underwater sound-absorbing structure of the present invention has the above-mentioned characteristics, and can be used to manufacture underwater equipment, such as the shells and walls of detectors and submersibles, to meet the needs of underwater shock absorption and noise reduction. It has broad engineering application prospects and can provide a new solution for underwater shock absorption and noise reduction of engineering structures and the multifunctional design of lightweight sandwich structures.

[0189] The present invention also provides an underwater equipment, which includes the underwater sound absorbing structure described in the above embodiments and comparative examples. The underwater equipment of the present invention can be a detector or a submersible, and the underwater sound absorbing structure can be used as its shell and / or wall surface, which can meet the needs of underwater shock absorption and noise reduction, has a very wide range of engineering application prospects, and provides a new solution for underwater shock absorption and noise reduction of engineering structures and multifunctional design of lightweight sandwich structures.

[0190] The present invention also provides a method for preparing an underwater sound absorbing structure, comprising the following steps:

[0191] The honeycomb cell 120 is prepared by introducing a molding process using a vacuum bag method: the carbon fiber sample is separated from the mold, and the sample is trimmed, polished and cut to obtain the honeycomb cell 120.

[0192] The cavity structure 122 and the resonance unit 121 are prepared by a layered casting method.

[0193] First, a raw material (such as polyurethane material) of a first thickness (such as 10 mm) is poured and filled in each honeycomb cell, and allowed to stand for a first predetermined time (such as 5 hours) so that the raw material (such as polyurethane material) has a certain strength.

[0194] Secondly, the cavity structure 122 is obtained by 3D printing or by preparing a corresponding cavity mold shell. Specifically, the 3D printing or cavity mold shell can be placed in the honeycomb cell 120 after precise positioning using a laser rangefinder, and the raw material (for example, polyurethane material) is continuously poured to a second thickness (for example, 30 mm), and the raw material (for example, polyurethane material) is allowed to stand for a second predetermined time (for example, 10 hours) so that the raw material (for example, polyurethane material) has the strength to withstand the resonance unit 121.

[0195] Finally, after precise positioning using a laser rangefinder, the resonance unit 121 is added, and the raw material (for example, polyurethane material) is continuously poured until the required overall thickness (for example, 50 mm) is reached.

[0196] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An underwater sound absorbing structure, characterized in that: It includes a honeycomb lattice structure, which includes a honeycomb support structure and a plurality of honeycomb cells arranged in the honeycomb support structure, each of the honeycomb cells includes a damping layer component, a resonance unit and a cavity structure are arranged inside the damping layer component, wherein the resonance unit is closer to the top of the honeycomb cell than the cavity structure.

2. The underwater sound absorbing structure according to claim 1, characterized in that: The resonance unit is a mass block, the height of the mass block is smaller than the thickness of the damping layer component, and the cross-sectional area of ​​the mass block is smaller than the cross-sectional area of ​​the honeycomb cell.

3. The underwater sound absorbing structure according to claim 2, characterized in that: The thickness of the mass block is 1 mm-20 mm; and / or The thickness of the air layer in the cavity structure is 1 mm-20 mm.

4. The underwater sound absorbing structure according to any one of claims 1 to 3, characterized in that: The height of the cavity structure is smaller than the thickness of the damping layer component, and the cross-sectional area of ​​the cavity structure is smaller than the cross-sectional area of ​​the honeycomb cell.

5. The underwater sound absorbing structure according to any one of claims 1 to 3, characterized in that: The number of the resonance unit and the number of the cavity structure are both one or more; and / or The resonance unit and the cavity structure are both located at a central position of the honeycomb cell in a width direction of the honeycomb cell.

6. The underwater sound absorbing structure according to any one of claims 1 to 3, characterized in that: The damping layer component is made of a polyurethane material having an equivalent isotropic loss factor greater than or equal to 0.5, and the height of the damping layer component is 45 mm-55 mm.

7. The underwater sound absorbing structure according to any one of claims 1 to 3, characterized in that: The honeycomb lattice structure also includes a bottom layer structure, which is located at the bottom of each honeycomb cell. The bottom layer structure is made of a polyurethane material with an equivalent isotropic loss factor greater than or equal to 0.5, and the thickness of the bottom layer structure is 5mm-15mm.

8. The underwater sound absorbing structure according to any one of claims 1 to 3, characterized in that: The honeycomb support structure includes a plurality of support members arranged in a honeycomb periodic pattern, and the support members meet one or more of the following conditions: The thickness of the support member is 1mm-2mm; The support member is made of a resin-based carbon fiber composite material or a resin-based glass fiber composite material; and The support member is provided with a connecting structure, and the connecting structure is used to connect the cavity structures in the adjacent honeycomb cells to form a connecting domain.

9. An underwater device, characterized in that: The underwater sound absorbing structure comprises the underwater sound absorbing structure according to any one of claims 1 to 8.

10. A method for preparing an underwater sound absorbing structure, characterized in that: The following steps are involved: Honeycomb cells are prepared by introducing a molding process using a vacuum bag method; Casting and filling a first thickness of raw material in each honeycomb cell, and leaving it to stand for a first predetermined time so that the raw material has a certain strength; After accurate positioning using a laser rangefinder, the 3D printed or cavity mold shell is placed in each honeycomb cell, and the raw material is poured to a first thickness, and allowed to stand for a second predetermined time so that the raw material has a strength capable of withstanding the resonance unit; The resonance unit is added after precise positioning using a laser rangefinder, and the raw materials are poured continuously until the required overall thickness is reached.

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