A combined granular damping underwater superstructure shell noise suppression device

Abstract

This invention discloses a combined particle-damped underwater superstructure hull noise suppression device, comprising an outer hull, an inner hull, and a superstructure connector; the inner hull and the outer hull are coaxially arranged and form a circumferential gap; several hull connecting blocks are arranged along the inner surface of the outer hull and the outer surface of the inner hull; the superstructure connector is arranged within the circumferential gap and periodically along the axial direction of the hull, and the superstructure connector is composed of several superstructure unit cells connected sequentially along the axial direction; the superstructure unit cell is a combined cubic structural unit, including a skeleton, a mass block, and a particle damping group; the skeleton is a hollow structure, forming a cavity inside; the skeleton is provided with connecting rods and connecting blocks to realize the fixed connection between adjacent superstructure unit cells and between the superstructure unit cells and the hull connecting blocks; the mass block is detachably connected to the skeleton; the particle damping group fills the cavity inside the skeleton.

Description

Technical Field

[0001] This invention belongs to the field of underwater vehicle noise reduction technology, specifically relating to a double-layer superstructure shell acoustic radiation suppression device that adopts a combined structure and introduces particle damping. Background Technology

[0002] In recent years, superstructures have demonstrated unique advantages in the field of elastic wave manipulation. By introducing periodic units into the structure, elastic waves can be scattered or attenuated within a specific frequency range, thereby creating bandgap characteristics and suppressing vibration and wave propagation. However, existing research has largely focused on flat plate structures or single-shell forms, and the unit cell structures are usually quite simple, resulting in limited suppression of low-frequency broadband vibrations and acoustic radiation.

[0003] As the applications of underwater vehicles in marine exploration, resource development, and national defense equipment continue to expand, their underwater stealth capabilities are receiving increasing attention. Among these, the structural vibrations generated by the external hull under the excitation of the propulsion system and internal equipment, and the resulting acoustic radiation, are significant sources of noise for underwater vehicles. Therefore, effectively suppressing the low-frequency acoustic radiation from the external hull of underwater vehicles has become a critical technical problem urgently needing to be solved in related fields.

[0004] Composite unit cell designs introduce mass concentration in localized areas, creating spatially non-uniform mass distribution within the unit cell. This type of design alters the mass distribution of the unit cell, changing its equivalent mass, equivalent stiffness, and inertial characteristics, thereby affecting the unit cell's equivalent dynamic parameters and its dynamic response characteristics within the structure. Furthermore, particle damping, a typical passive energy dissipation technique, relies on the relative slippage, collisions, and friction between particles and between particles and cavity walls to dissipate energy, offering advantages in the low-to-mid frequency range. However, traditional particle damping struggles to effectively modulate the elastic wave propagation path and the overall structural dynamics, and its noise reduction effect remains limited when used alone.

[0005] In summary, by introducing periodic superstructures into the double-layer shell, utilizing the mass concentration of the composite structure, and combining it with the particle damping energy dissipation mechanism, it is expected to effectively suppress low-frequency broadband noise in the outer shell of underwater vehicles, thereby improving their overall stealth performance and engineering applicability. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and solve the problem of insufficient low-frequency noise reduction effect of existing underwater vehicles. It provides a combined particle-damped underwater superstructure shell noise suppression device, which achieves low-frequency broadband acoustic radiation suppression of the double-shell structure by combining superstructure bandgap, local mass concentration and particle damping energy dissipation mechanism.

[0007] The objective of this invention is achieved through the following technical solution: A combined particle-damped underwater superstructure hull noise suppression device includes an outer hull, an inner hull, and a superstructure connector; The inner shell and the outer shell are coaxially arranged and are spaced apart in the radial direction to form a circumferential gap between the inner shell and the outer shell for installing the superstructure connector. The inner surface of the outer shell and the outer surface of the inner shell are provided with a plurality of shell connecting blocks at intervals along the axial and circumferential directions of the shell, and the connecting blocks correspond to each other in spatial position; The superstructure connector is disposed within the circumferential gap and periodically arranged along the axial direction of the shell. The superstructure connector is composed of several superstructure unit cells connected sequentially along the axial direction. The superstructure unit cell is a combined cubic structural unit, including a framework, mass blocks, and particle damping groups. The skeleton is a hollow structure with an internal cavity; the skeleton is provided with several chamfered areas and connecting rods and connecting blocks in the chamfered areas, which are used to realize the fixed connection between adjacent superstructure unit cells and between the superstructure unit cells and the shell connecting blocks. The mass block is detachably connected to the skeleton and, after assembly, seals the internal space of the skeleton, so that the particle damping group is stably set inside the skeleton. The particle damping group fills the cavity inside the skeleton.

[0008] Furthermore, the skeleton is provided with a filling opening for installing the particle damping group and a threaded hole for fastening connection; the mass block is provided with a boss and a threaded hole; the superstructure unit cell also includes a connecting piece and a fastener, the connecting piece is provided with a threaded through hole, the fastener passes through the threaded through hole and cooperates with the threaded hole on the skeleton or the mass block, so that the mass block is detachably fixed to the skeleton and the filling opening is closed.

[0009] Furthermore, the particle damping group consists of several solid spheres; the solid spheres are in contact with each other and arranged alternately within the cavity of the skeleton, so as to undergo relative slippage, collision and friction under the action of structural vibration.

[0010] Furthermore, the inner surface of the outer shell and the outer surface of the inner shell are respectively provided with an outer shell connecting block and an inner shell connecting block, and the outer shell connecting block and the inner shell connecting block are fixedly connected to the superstructure connector by welding.

[0011] Furthermore, the skeleton is made of aluminum alloy and the mass block is made of stainless steel to introduce mass concentration characteristics in local areas of the superstructure unit cell.

[0012] Furthermore, the outer shell, the inner shell, and the particle damping group are all made of stainless steel.

[0013] Furthermore, the combined connection of the skeleton and mass blocks in the superstructure unit cell introduces spatially uneven mass and stiffness characteristics into the structure, causing the elastic wave to deflect during propagation.

[0014] Furthermore, the outer shell and the inner shell are connected by several superstructure connectors to form an integral structure, so that vibrations and waves pass through multiple connectors in sequence during the propagation process from the inside to the outside, thereby achieving multi-level adjustment and gradual attenuation.

[0015] Furthermore, the vibration source is located on the inner wall of the inner shell. The structural vibration first acts on the inner shell and then propagates to the outer shell through the superstructure connector.

[0016] Furthermore, the external hull structure used in underwater vehicles is designed to reduce the acoustic radiation generated during operation.

[0017] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: 1. This invention introduces the Bragg scattering mechanism by periodically arranging superstructure unit cells along the axial direction of the inner and outer shells; this causes elastic waves to scatter and attenuate within a specific frequency range, forming bandgap characteristics, thereby effectively suppressing the propagation of elastic waves and broadband acoustic radiation in the low-frequency range.

[0018] 2. This invention, by incorporating stainless steel mass blocks in certain areas of the skeleton and a lightweight aluminum alloy frame, creates spatially non-uniform mass and stiffness characteristics within the unit cell (introducing local mass concentration), altering the structure's equivalent dynamic parameters. This causes path deflection and redistribution of elastic waves during propagation, enhancing the structure's dynamic non-uniformity and thus broadening the effective vibration reduction and noise reduction frequency band.

[0019] 3. This invention involves filling a closed hollow framework with a group of particle dampers. Under external excitation, relative slippage, collisions, and friction occur between the particles and between the particles and the inner wall of the framework, converting mechanical energy into heat energy for dissipation. This mechanism significantly enhances the overall damping level and effectively attenuates elastic waves outside the bandgap frequency range, compensating for the insufficient noise reduction capability of single-periodic superstructures in non-bandgap frequency bands.

[0020] 4. The skeleton and mass block of this invention are detachably connected by connecting pieces and fasteners, and the superstructure unit cells are standardly spliced; this not only facilitates manufacturing, transportation and on-site installation, reducing costs, but more importantly, it gives the device adjustable parameters, which can flexibly change and adjust the parameters of mass block or particle damping according to the size, operating conditions and target noise reduction frequency band of different underwater vehicles, greatly improving engineering adaptability.

[0021] 5. This invention combines a double-shell structure, periodic bandgap, dynamic non-uniform modulation, and particle energy dissipation; when vibration propagates from the inside to the outside, it is successively subjected to multi-level regulation and weakening, realizing the synergistic effect of multiple noise reduction mechanisms of "suppression-deflection-dissipation", avoiding the risk of failure of traditional single-mechanism noise reduction devices in specific frequency bands.

[0022] 6. The superstructure connector of the present invention serves as a functional connection unit between two shell layers, simultaneously undertaking the triple functions of structural connection, load transfer, and noise regulation, thus avoiding the problem that traditional support structures only have a single mechanical function.

[0023] 7. This invention combines periodic superstructure with particle damping, enabling the device to exhibit different dominant suppression mechanisms in different frequency ranges, thus avoiding the problem of traditional single-mechanism noise reduction devices failing in specific frequency bands.

[0024] 8. The superstructure unit cell of the present invention adopts a modular design, and the unit cells are spliced ​​together through a standard connection method, which facilitates manufacturing, transportation and on-site installation, while reducing the manufacturing and maintenance costs of the overall device.

[0025] 9. This invention is applicable to cylindrical shell structures, does not depend on specific shell size or thickness parameters, and has good applicability and scalability for the external shells of underwater vehicles of different sizes. Attached Figure Description

[0026] Figure 1 This is a perspective structural diagram of the noise suppression device in an example of the present invention.

[0027] Figure 2 This is a schematic diagram of the noise suppression device in an example of the present invention.

[0028] Figure 3 This is a perspective structural diagram of the superstructure connector in an example of the present invention.

[0029] Figure 4 This is a schematic diagram of the layered exploded structure of the superstructure connector in an example of the present invention.

[0030] Figure 5 This is a perspective structural diagram of a superstructure unit cell in an example of the present invention.

[0031] Figure 6This is a schematic diagram of the exploded structure of the superstructure unit cell in an example of the present invention.

[0032] Figure 7 This is a schematic diagram of the structure of the particle damping group in an example of the present invention.

[0033] Figure 8 This is a schematic diagram of the skeleton structure in an example of the present invention.

[0034] Figure 9 This is a schematic diagram of the mass block structure in an example of the present invention.

[0035] Figure 10 This is a partial perspective structural diagram of a superstructure unit cell in an example of the present invention.

[0036] Figure 11 This is a cross-sectional view of the noise suppression device in an example of the present invention.

[0037] Figure 12 This is a partial cross-sectional view of the noise suppression device in an example of the present invention.

[0038] Figure 13 This is a right-view perspective structural diagram of the noise suppression device in an example of the present invention.

[0039] Figure 14 This is a partial perspective right-view structural schematic diagram of the noise suppression device in an example of the present invention.

[0040] Figure 15 This is an acceleration response curve diagram in an example of the present invention.

[0041] Figure 16 This is a sound pressure level response curve in an example of the present invention.

[0042] Reference numerals: 1-Outer shell, 2-Inner shell, 3-Superstructure connector, 10-Outer shell connector, 20-Inner shell connector, 30-Superstructure unit cell, 300-Skeleton, 301-Mass block, 302-Connecting piece, 303-Hex socket screw, 304-Particle damping group, 3000-Connecting rod, 3001-Skeleton connector, 3002-Filling opening, 3003-Threaded hole, 3010-Boss, 3011-Threaded hole, 3020-Threaded through hole. Detailed Implementation

[0043] The embodiments of the present invention will be further described below with reference to the accompanying drawings. The embodiments shown in the drawings are only for illustrating the technical solutions of the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0044] This invention provides a combined particle-damped underwater superstructure hull noise suppression device, which can be used as the external hull structure of an underwater vehicle. The device employs an inner and outer double-shell configuration, coaxially connected by multiple sets of superstructure connectors. These superstructure connectors are arranged along the axial direction of the hull and are formed by a periodic arrangement of multiple combined superstructure unit cells. They are reliably fixed to the inner and outer hulls via connecting blocks, forming a stable integral structure in the axial direction. The vibration source is installed and supported through the inner hull. Its structural form can be configured in conjunction with the overall design of the underwater vehicle to meet the requirements of installation reliability and vibration transmission performance.

[0045] Through the above structural design, the device provided in this embodiment of the invention exhibits excellent noise reduction performance. On one hand, the superstructure connector is composed of composite superstructure unit cells arranged periodically along the axial direction. The periodic structure exhibits Bragg scattering during elastic wave propagation, forming a band gap within a specific frequency range, thereby significantly suppressing the propagation capability of elastic waves in this frequency band and reducing the structural acoustic radiation level. On the other hand, the non-uniform geometric configuration and the arrangement of local mass blocks within the unit cells introduce spatially uneven mass and stiffness characteristics into the structure, enhancing the dynamic non-uniformity of the system and causing a redistribution of vibration and wave propagation, thus reducing the overall response. Simultaneously, the particle damping arranged within the unit cell skeleton generates relative motion under structural vibration, dissipating vibration energy through collisions and friction, further attenuating elastic waves outside the band gap.

[0046] This embodiment provides a combined particle-damped underwater superstructure hull noise suppression device, such as... Figures 1 to 4 As shown, the device includes an outer shell 1, an inner shell 2, and multiple sets of superstructure connectors 3 disposed between them. The outer shell 1 and the inner shell 2 are coaxially arranged and structurally connected by multiple sets of superstructure connectors 3, forming a stable double-shell structure. The superstructure connectors 3 are arranged along the axial direction of the shell and are periodically distributed, allowing elastic waves to pass through multiple structural units sequentially during axial propagation. In this embodiment, both the outer shell 1 and the inner shell 2 are made of stainless steel to ensure the overall structural strength, corrosion resistance, structural reliability in underwater service environments, and engineering applicability.

[0047] like Figures 5 to 7As shown, the superstructure connector 3 is composed of multiple periodically arranged superstructure unit cells 30. Each superstructure unit cell 30 is a composite cubic structure, including a skeleton 300, mass blocks 301, connecting pieces 302, hexagonal screws 303, and particle damping groups 304. The skeleton 300 is made of aluminum alloy to reduce structural weight; the mass blocks 301 are made of stainless steel and are used to introduce local mass modulation, i.e., to introduce mass concentration in local areas of the superstructure unit cell, creating a spatially uneven mass distribution within the unit cell, thereby changing the equivalent dynamic parameters of the unit cell and enhancing the dynamic modulation capability of the geometrically reconstructed superstructure; the particle damping groups 304 fill the interior of the skeleton 300 and are composed of solid stainless steel spheres. In this embodiment, each superstructure unit cell 30 contains 44 solid stainless steel spheres, and the unit cell contains 4 mass blocks 301, 12 connecting pieces 302, and 12 hexagonal screws 303. Under structural vibration, the 304 particle damping group can generate relative motion within the skeleton. Solid stainless steel spheres contact each other and are arranged alternately within the skeleton cavity. The particle damping undergoes relative slippage, collision, and friction, which is beneficial for energy dissipation. Energy dissipation is achieved through collisions and friction between particles and between particles and the inner wall of the skeleton. In this embodiment, the skeleton, connecting plates, and mass blocks are detachably fixed together using fasteners, giving the superstructure unit cell good assemblability and maintainability, facilitating the replacement and adjustment of the mass blocks or particle damping group according to actual engineering needs. The periodic arrangement of the superstructure unit cells in the structure introduces the Bragg scattering mechanism, causing elastic waves to scatter and attenuate within a specific frequency range, thereby forming bandgap characteristics and suppressing the propagation of vibrations and waves. The skeleton and mass blocks in the superstructure unit cell are combined and connected, introducing spatially uneven mass and stiffness characteristics into the structure, causing path deflection of elastic waves during propagation. The structural parameters of the superstructure unit cell include the unit cell size and the mass block mass, which can be adjusted according to different noise suppression requirements.

[0048] like Figure 8 and Figure 9As shown, the skeleton 300 is a hollow structure, forming a particle filling space inside. The four corners (chamfered areas) of the skeleton 300 are connected to the adjacent superstructure unit cell 30 via connecting rods 3000 and skeleton connecting blocks 3001, thereby ensuring the continuity and overall stability of the superstructure connector 3 in the axial direction. The skeleton 300 is provided with a filling opening 3002 and a threaded hole 3003. The filling opening 3002 is used for loading the particle damping group 304, and the threaded hole 3003 is used to seal the filling opening by threading. The mass block 301 is set in other chamfered areas of the skeleton 300, and is provided with a boss 3010 and a threaded hole 3011, and is fixedly connected to the skeleton 300 via a connecting piece 302; the boss 3010 is adapted to the shape of the filling opening 3002 and is inserted into the opening to improve the tightness of the seal and the compactness of the structure; and to make the particle damping closely tangentially arranged, and the particle damping is tangential to the surface of the mass block boss. Under external excitation, relative sliding, collision and friction occur between particles and between particles and the inner wall of the skeleton and the protrusions of the mass block, converting mechanical energy into heat energy and dissipating it.

[0049] In this embodiment, the skeleton, mass block, and connecting piece are formed by CNC machining or additive manufacturing processes to improve the machining accuracy of the parts, the consistency of assembly, and the reliability of the overall structure, thereby meeting the needs of engineering applications.

[0050] The skeleton 300 is a hollow cube with chamfered corners. The cube has 8 corners cut off, 4 of which are diagonally cut off for connecting rods, and the remaining corners are used to fill particle damping and place mass blocks. The hollow part of the skeleton forms a particle filling space.

[0051] like Figure 10 The diagram shows a partial perspective view of the superstructure unit cell 30, clearly illustrating the relative positions of the skeleton 300, the mass block 301, and the particle damping group 304. The connecting piece 302 has two threaded through holes 3020, which are connected to the skeleton 300 and the mass block 301 respectively via hexagonal socket screws 303. This reliably fixes the mass block 301 to the skeleton 300 and forms a closed structure for the particle damping group 304 inside the skeleton 300. Multiple superstructure unit cells 30 are sequentially spliced ​​together in the axial direction via connecting rods 3000 and skeleton connecting blocks 3001 to form the integral superstructure connector 3.

[0052] like Figure 11 and Figure 12The diagram shows a cross-sectional view and a partial cross-sectional view of the noise suppression device in an embodiment of the present invention. As can be seen from the cross-sectional view, the superstructure connector 3 is disposed between the outer shell 1 and the inner shell 2, and is reliably fixed by connecting blocks. The superstructure connector 3 is fixedly connected to the outer shell 1 and the inner shell 2 respectively by the outer shell connecting block 10 and the inner shell connecting block 20. The outer shell connecting block 10 and the inner shell connecting block 20 are fixed to their respective shells by welding to improve the overall rigidity and long-term service stability of the connection, preventing connection failure due to vibration or impact in underwater conditions. Vibrations and waves can be effectively transmitted from the inner shell 2 to the interior of the superstructure connector 3. During the propagation of elastic waves from the inner shell 2 to the outer shell 1, they need to pass through multiple superstructure unit cells 30 sequentially, thereby achieving progressive modulation and attenuation within the structure.

[0053] like Figure 13 and Figure 14 The diagram shows a right-view perspective view and a partial right-view perspective view of the noise suppression device in this embodiment of the invention. The right-view perspective view allows for a direct observation of the overall assembly relationship between the outer shell 1, the inner shell 2, and the superstructure connector 3, as well as the periodic distribution characteristics of the superstructure connector 3 in the axial direction. The symmetrical arrangement of the connecting blocks in the circumferential and axial directions ensures good stress balance under load and vibration, which is beneficial for the uniform transmission and stable diffusion of load and vibration within the structure, thereby ensuring the consistency and reliability of the overall noise reduction performance of the device.

[0054] The working principle of the combined particle-damped underwater superstructure hull noise suppression device according to the above-described embodiments is as follows: The superstructure connector is formed by multiple superstructure unit cells arranged periodically along the axial direction of the shell, giving the overall structure a significant periodic characteristic during elastic wave propagation. As elastic waves propagate axially, the periodically arranged superstructure unit cells produce a significant Bragg scattering effect, forming a bandgap structure within a specific frequency range, thus significantly weakening the propagation capability of elastic waves in that frequency band. By restricting the effective propagation of elastic waves within the structure, the transmission of vibration and wave motion to the outer shell is reduced, thereby lowering the structural acoustic radiation level.

[0055] The superstructure unit cell, through a combination of skeleton and local mass blocks, introduces non-uniformly distributed mass and stiffness characteristics in space, resulting in significant dynamic non-uniformity of the structural system. During elastic wave propagation, differences in inertia and stiffness in different regions cause changes in wave characteristics, leading to reflection, scattering, and mode redistribution within the unit cell, thereby altering the original propagation path and wave distribution. This non-uniform dynamic characteristic further disrupts the continuous transmission of elastic waves within the structure, providing favorable conditions for the attenuation and dissipation of vibrations and waves.

[0056] Under the action of the internal excitation device, the particle damping group set inside the unit cell of the superstructure generates relative motion within the skeletal constraint space. Frequent collisions and friction occur between the particles and between the particles and the inner wall of the skeletal framework, thereby converting and dissipating some of the mechanical energy. This particle damping energy dissipation mechanism not only enhances the overall damping level of the structure, but also effectively attenuates elastic waves that can still propagate outside the bandgap frequency range, thus compensating for the insufficient noise reduction capability of single-periodic superstructures in the non-bandgap frequency band.

[0057] Furthermore, the device employs a double-shell structure with inner and outer shells. The vibration source is located on the inner wall of the inner shell, and the vibration initially excites the inner shell to generate a response. As the elastic wave propagates towards the outer shell, it must pass through multiple superstructure connectors sequentially, attenuating step by step under the combined effects of periodic scattering, dynamic non-uniform modulation, and particle damping energy dissipation. Through the coordinated operation of the double-shell structure and the intermediate superstructure connectors, vibrations and waves are effectively controlled and weakened at multiple levels along the transmission path, thereby achieving effective suppression of structural acoustic radiation while ensuring the overall structural continuity and load-bearing capacity.

[0058] This invention provides simulation results of the acceleration response curve and sound pressure level response curve of the noise suppression device from 0 Hz to 1000 Hz. For example... Figure 15 and Figure 16 As shown in the results, the device exhibits significant vibration response and reduced sound radiation levels across multiple frequency bands, including below 290Hz, 340Hz to 540Hz, 630Hz to 680Hz, and above 780Hz. These results demonstrate that the synergistic effect of the superstructure connector and particle damping employed in this embodiment of the invention can effectively suppress structural vibration and sound radiation over a wide frequency range, verifying the engineering application potential of this structural form in noise control. In the specific simulation, the outer shell diameter was 340.8mm, the inner shell diameter was 225.5mm, the unit cell side length was 40.0mm, and the mass block weight was 56.2g.

[0059] In summary, the underwater superstructure hull noise suppression device with combined particle damping proposed in this invention combines the periodic modulation characteristics of the superstructure unit cell with the energy dissipation mechanism of particle damping. It simultaneously introduces bandgap suppression, dynamic non-uniformity, and energy dissipation mechanisms into the structure, enabling the device to effectively suppress structural acoustic radiation over a wide low-frequency range. While maintaining the overall continuity and load-bearing capacity of the hull, the device achieves multi-stage attenuation of vibrations and waves along the propagation path, demonstrating good engineering applicability.

[0060] Furthermore, the embodiments of this invention employ a modular superstructure connector combined with a double-layer shell structure, resulting in overall structural stability and flexible manufacturing and assembly processes. Parameter adjustments and structural expansions can be made according to the structural layout and service requirements of different underwater vehicles, demonstrating good versatility and feasibility. This device requires no external control system, introduces no electromagnetic interference, and maintains stable noise reduction performance even in complex environments.

[0061] Those skilled in the art should understand that the above embodiments are only used to illustrate the technical concept and implementation of the present invention, and are not intended to limit the scope of protection of the present invention. Any structural adjustments, parameter changes, or equivalent substitutions made by those skilled in the art based on the content of the present invention without departing from the technical concept and scope defined by the claims should be considered to fall within the scope of protection of the present invention.

Claims

1. A combined particle-damped underwater superstructure hull noise suppression device, characterized in that, It includes an outer shell (1), an inner shell (2), and a superstructure connector (3); The inner shell (2) and the outer shell (1) are coaxially arranged and are spaced apart in the radial direction to form a circumferential gap between the inner shell (2) and the outer shell (1) for installing the superstructure connector (3); The inner surface of the outer shell (1) and the outer surface of the inner shell (2) are provided with a number of shell connecting blocks at intervals along the axial and circumferential directions of the shell, and the connecting blocks correspond to each other in spatial position; The superstructure connector (3) is disposed in the circumferential gap and periodically arranged along the axial direction of the shell. The superstructure connector (3) is composed of several superstructure unit cells (30) connected sequentially along the axial direction. The superstructure unit cell (30) is a combined cubic structural unit, including a skeleton (300), a mass block (301), and a particle damping group (304). The skeleton (300) is a hollow structure with a cavity inside; the skeleton (300) is provided with several chamfered areas and connecting rods (3000) and connecting blocks (3001) are provided in the chamfered areas to realize the fixed connection between adjacent superstructure unit cells (30) and between superstructure unit cells (30) and the shell connecting blocks; The mass block (301) is detachably connected to the skeleton (300) and, after assembly, seals the internal space of the skeleton (300), so that the particle damping group (304) is stably set inside the skeleton (300). The particle damping group (304) fills the cavity inside the skeleton (300).

2. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The skeleton (300) is provided with a filling opening (3002) for installing the particle damping group (304) and a threaded hole (3003) for fastening connection; the mass block (301) is provided with a boss (3010) and a threaded hole (3011); the superstructure unit cell (30) also includes a connecting piece (302) and a fastener, the connecting piece (302) is provided with a threaded through hole (3020), the fastener passes through the threaded through hole (3020) and cooperates with the threaded hole on the skeleton (300) or the mass block (301), so that the mass block (301) is detachably fixed on the skeleton (300) and the filling opening (3002) is closed.

3. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The particle damping group (304) consists of several solid spheres; the solid spheres are in contact with each other and arranged alternately in the cavity of the skeleton (300) so that they can slide, collide and rub against each other under the action of structural vibration.

4. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The inner surface of the outer shell (1) and the outer surface of the inner shell (2) are respectively provided with an outer shell connecting block (10) and an inner shell connecting block (20). The outer shell connecting block (10) and the inner shell connecting block (20) are fixedly connected to the superstructure connector (3) by welding.

5. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The skeleton (300) is made of aluminum alloy and the mass block (301) is made of stainless steel to introduce mass concentration characteristics in local areas of the superstructure unit cell (30).

6. A combined particle-damped underwater superstructure hull noise suppression device according to claim 1 or 5, characterized in that, The outer shell (1), the inner shell (2), and the particle damping group (304) are all made of stainless steel.

7. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The skeleton (300) and mass block (301) in the superstructure unit cell (30) are combined and connected to introduce spatially uneven mass and stiffness characteristics into the structure, so that the elastic wave will deflect during propagation.

8. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The outer shell (1) and the inner shell (2) are connected by several superstructure connectors (3) to form an integral structure, so that vibration and wave propagation from the inside to the outside passes through multiple connectors in sequence, achieving multi-level adjustment and gradual attenuation.

9. The underwater superstructure hull noise suppression device with combined particle damping according to claim 1, characterized in that, The vibration source is located on the inner wall of the inner shell (2). The structural vibration first acts on the inner shell and then propagates to the outer shell through the superstructure connector.

10. A combined particle-damped underwater superstructure hull noise suppression device according to claim 1, characterized in that, The external hull structure used for underwater vehicles to reduce the acoustic radiation generated by the underwater vehicle during operation; the frequency range in which the suppression device has the effect of suppressing the acoustic radiation of the hull structure includes the frequency bands below 290Hz, 340Hz to 540Hz, 630Hz to 680Hz, and above 780Hz.

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