A particle damping noise suppression superstructure device based on mode conversion function

Abstract

The application discloses a granular damping noise suppression superstructure device based on mode conversion function, which comprises an outer shell, an inner shell, a noise reduction ring and a connecting device. A plurality of noise reduction rings are periodically arranged along the shell in the axial direction, and the outer shell and the inner shell are assembled and connected through the connecting device, so that a double-layer shell structure with periodic characteristics is formed, a band gap characteristic is introduced, and low-frequency sound radiation suppression is realized. The noise reduction ring comprises an inner hexagonal screw, a cover plate, a granular damping group and an integrated annular frame, the inside of the integrated annular frame is composed of a plurality of unit structures, each unit structure is formed by rotating the granular damping group and a cavity, the unit structures are arranged in a non-mirror-symmetrical manner, and the propagation of structural vibration and elastic waves is effectively suppressed, the granular damping group is composed of double-radius solid spheres arranged closely, and the noise reduction frequency band is widened through the synergistic effect of different radius particles. The device can be used for the outer shell structure of an underwater vehicle to realize low-frequency broadband noise suppression effect.

Description

Technical Field

[0001] This invention belongs to the field of noise suppression technology, and particularly relates to a particle-damped noise suppression superstructure device based on mode conversion function. Background Technology

[0002] Superstructures are typically composed of periodically arranged structural units, and their overall performance depends not only on the material itself but also on their geometric configuration and spatial arrangement. By rationally designing the periodic structural parameters, superstructures can generate band gaps and modulate vibrations and waves within a specific frequency range. Based on the application potential of superstructures in the low-frequency and mid-low-frequency ranges, they are gradually being applied to engineering scenarios for sound radiation suppression.

[0003] In engineering equipment such as underwater vehicles, structural radiated noise is one of the important factors affecting their acoustic performance. Vibrations generated by internal equipment during operation propagate outward through the hull and enter the water as sound radiation, forming detectable noise signals. Double-hull structures are widely used in underwater vehicles, using connecting or isolating structures between the inner and outer hulls to attenuate vibrations and waves during propagation. However, traditional double-hull structures often rely on continuous structures or uniform damping materials, and their noise reduction effect is significantly limited by frequency. Therefore, how to introduce effective and controllable noise reduction units into double-hull structures has become an urgent problem to be solved in the field of underwater vehicle noise control.

[0004] Particle damping, as a typical passive energy dissipation method, is widely used in vibration and noise control due to its simple structure and strong adaptability. The relative motion of particles can continuously dissipate energy through friction and collision, which is particularly effective in the low-frequency range. However, relying solely on the characteristics of periodic structures often fails to achieve stable suppression effects over a wide frequency range. Therefore, by introducing mode switching into periodic structures, the form and path of wave propagation are altered, weakening their transmission capacity. The synergistic effect of these two methods can further improve the overall noise reduction performance of the structure. Summary of the Invention

[0005] This invention aims to overcome the problem of insufficient noise suppression in the prior art and provides a particle-damped noise suppression superstructure device based on mode switching function. This invention combines the periodic characteristics of the superstructure, the mode switching control method and the particle damping energy dissipation mechanism, and rationally designs a double-shell structure, which can effectively suppress structural noise, thereby providing a reliable and practical noise suppression solution for engineering equipment such as underwater vehicles.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A particle-damped noise suppression superstructure device based on mode conversion function, comprising:

[0008] The outer shell and the inner shell are coaxial and spaced apart in the radial direction;

[0009] At least one noise reduction ring is disposed between the outer shell and the inner shell, the noise reduction ring comprising an integral ring frame and a particle damping group disposed in the internal space of the integral ring frame;

[0010] A connecting device is used to fix the noise reduction ring to the outer shell and the inner shell respectively.

[0011] Furthermore, the inner wall of the outer shell is provided with a plurality of outer shell connecting blocks along the circumferential and axial directions; the outer wall of the inner shell is provided with a plurality of inner shell connecting blocks; the connecting device cooperates with the outer shell connecting blocks and the inner shell connecting blocks to realize the detachable connection of the noise reduction ring.

[0012] Furthermore, the integrated annular frame has several structural units arranged in a circular direction. Each unit structure is formed by rotating several damping cavities. The damping cavities and the cover plate form a closed space for accommodating the particle damping group.

[0013] Furthermore, the structural units inside the integrated ring frame are arranged in a non-mirror symmetrical manner, allowing vibrations and waves to propagate in several coupling forms; there are a total of 12 structural units, and the damping cavities in each structural unit are arranged in a spatial arrangement that rotates 120° sequentially to form a mode-changing structure.

[0014] Furthermore, the particle damping group includes large particles with a first radius and small particles with a second radius; the large particles and the small particles are arranged alternately and tangentially in the damping cavity, and particles with different radii form different dynamic responses under external action, thus broadening the effective noise reduction frequency band.

[0015] Furthermore, the plurality of noise reduction rings are arranged periodically at equal intervals along the axial direction of the inner shell to generate the Bragg bandgap effect, suppressing the propagation of vibration and waves.

[0016] Furthermore, the outer and inner sides of the integrated ring frame are respectively provided with an outer reinforcing ring and an inner reinforcing ring; the outer reinforcing ring is provided with an outer connecting groove, and the inner reinforcing ring is provided with an inner connecting groove; the connecting piece of the connecting device is embedded in the connecting groove and is connected to the outer shell connecting block and the inner shell connecting block by fasteners.

[0017] Furthermore, the device has a sound radiation suppression effect in the frequency bands below 420Hz, 500Hz to 660Hz, 730Hz to 870Hz, and above 920Hz.

[0018] Furthermore, the integrated ring frame is integrally formed using CNC machining or additive manufacturing processes, and the outer shell, inner shell, and noise reduction ring are made of stainless steel.

[0019] The present invention also provides an application of the above-mentioned particle damping noise suppression superstructure device for the external shell structure of an underwater vehicle to reduce the noise radiation generated during its operation.

[0020] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0021] 1. This invention abandons the traditional approach of relying on uniform damping materials in double-shell structures. It innovatively integrates a periodic superstructure (Bragg scattering attenuation), spatially non-mirror-symmetric arrangement (mode conversion alters propagation paths), a dual-radius particle damping group (friction and collision energy dissipation), and a double-shell structure to form a multi-mechanism synergistic noise suppression system. The axially periodically arranged noise reduction rings introduce Bragg scattering into the structure, causing vibrations and waves to be reflected and attenuated within a specific frequency range. Simultaneously, mode conversion based on the unit structure's geometric configuration alters the structure's vibration form and wave propagation path. The particle damping group undergoes relative sliding, collision, and friction within the cavity, further dissipating energy. The double-shell structure enhances spatial isolation and dispersion. The superposition and synergistic effect of these multiple mechanisms enable this invention to exhibit excellent noise suppression performance in both low and mid-low frequency ranges, surpassing traditional structures with single noise reduction mechanisms.

[0022] 2. This invention employs a dual-radius particle damping group design. By using particles of different radii to form different equivalent dynamic characteristics within the same damping cavity, the device generates different bandgap effects in different frequency ranges, thereby achieving common suppression of multiple frequency bands. This significantly broadens the low-frequency and mid-low-frequency noise reduction bands that are crucial for underwater vehicles, improves the overall wide low-frequency noise reduction capability, and produces a synergistic effect of multi-band, wide-band noise reduction.

[0023] 3. The device of this invention employs a detachable multi-node local connection method (connected by inner and outer shell connecting blocks and a reinforcing ring) to connect the inner and outer shells, achieving localized connection between the noise reduction ring and the shell. This design disperses the load in physical space, ensuring that vibrations and waves, as they propagate from the inside out, must sequentially pass through multiple functional units within the noise reduction ring. Through this continuous modulation, the energy is gradually weakened, thereby effectively suppressing acoustic radiation from the shell structure over a wide frequency range. While reducing radiated noise, it also reduces local stress concentration, improving load-bearing capacity and structural safety in deep-water, high-pressure environments, thus balancing acoustic isolation and mechanical stability.

[0024] 4. The detachable and splicable design of the noise reduction ring and connecting module facilitates assembly, maintenance and replacement; it enables engineers to flexibly increase or decrease the number of noise reduction rings or adjust the particle ratio inside the cavity according to the excitation frequency of a specific underwater vehicle, realizing the customization of structural parameters and excellent engineering maintenance and adaptability.

[0025] 5. The integrated ring frame of the present invention is integrally formed by CNC machining or additive manufacturing process, which can effectively ensure the structural dimensional accuracy and assembly consistency, reduce the errors and assembly instability caused by traditional splicing structures, and improve the overall strength, reliability and long-term underwater service performance of the device.

[0026] 6. This invention is a purely passive noise suppression device that requires no external energy input or complex control system. It has the advantages of simple structure, high reliability, and strong environmental adaptability. It is particularly suitable for long-term underwater operation and has good promotion value in engineering applications. Attached Figure Description

[0027] Figure 1 This is a perspective structural diagram of the noise reduction device provided in an embodiment of the present invention.

[0028] Figure 2 This is a partial perspective structural diagram of the noise reduction device provided in an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the left-view structure of the noise reduction device provided in an embodiment of the present invention.

[0030] Figure 4 This is a perspective structural diagram of the outer shell and inner shell provided in an embodiment of the present invention.

[0031] Figure 5 This is a schematic diagram of the left-view structure of the noise reduction ring provided in an embodiment of the present invention.

[0032] Figure 6 This is an exploded structural diagram of the noise reduction ring provided in an embodiment of the present invention.

[0033] Figure 7 This is a schematic diagram of a partial explosion structure of the noise reduction ring provided in an embodiment of the present invention.

[0034] Figure 8 This is a partial perspective view of the left side of the noise reduction ring provided in an embodiment of the present invention.

[0035] Figure 9 This is a schematic diagram of the outer partial structure of the integrated ring frame provided in an embodiment of the present invention.

[0036] Figure 10 This is a schematic diagram of the inner partial structure of the integrated ring frame provided in an embodiment of the present invention.

[0037] Figure 11 This is a schematic diagram of the exploded left side structure of the connecting device provided in an embodiment of the present invention.

[0038] Figure 12 This is a schematic diagram of the exploded right side structure of the connecting device provided in an embodiment of the present invention.

[0039] Figure 13 This is a cross-sectional structural diagram of the noise reduction device provided in an embodiment of the present invention.

[0040] Figure 14 This is a partial cross-sectional view of the noise reduction device provided in an embodiment of the present invention.

[0041] Figure 15 This is an acceleration response curve diagram of an embodiment of the present invention.

[0042] Figure 16 This is a sound pressure level response curve diagram of an embodiment of the present invention.

[0043] Reference numerals: 1-Outer shell, 2-Inner shell, 3-Noise reduction ring, 4-Connecting device, 10-Outer shell connecting block, 20-Inner shell connecting block, 30-Hex socket screw, 31-Cover plate, 32-Particle damping group, 33-Integral ring frame, 40-Outer connecting piece, 41-Inner connecting piece, 42-Cylindrical head screw, 43-Flat washer, 44-Nut, 310-Threaded hole, 330-Threaded through hole, 331-Outer reinforcing ring, 332-Outer groove, 333-Outer connecting groove, 334-Circular through hole, 335-Inner reinforcing ring, 336-Inner groove, 337-Inner connecting groove, 338-Circular through hole. Detailed Implementation

[0044] The present invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that these embodiments are only used to illustrate the technical solutions of the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0045] A particle damping noise suppression superstructure device based on mode conversion function according to an embodiment of the present invention can be used as the external shell structure of an underwater vehicle.

[0046] See Figures 1 to 3 As shown, the device is a coaxially arranged double-shell structure, including an outer shell 1, an inner shell 2, multiple noise reduction rings 3, and connecting devices 4. Both the outer shell 1 and the inner shell 2 are thin-walled shell structures, coaxially arranged to form a double-shell structure in the radial direction, used to simulate or apply to the external load-bearing and acoustic radiation environment of structures such as underwater vehicles. The inner wall of the inner shell 2 can be used to house internal vibration sources or vibration equipment of the vehicle; its specific structural form can be adjusted according to the overall layout and installation requirements of the vehicle.

[0047] Multiple noise reduction rings 3 are sequentially arranged between the outer shell 1 and the inner shell 2 along the axial direction of the device. In this embodiment, three noise reduction rings are provided, and each noise reduction ring is arranged at equal intervals along the axial direction. The noise reduction rings at different axial positions modulate vibration and wave, which helps to broaden the effective noise reduction frequency band of the shell structure and enhance the low-frequency suppression capability. Each noise reduction ring 3 consists of an integrated ring frame, a cover plate, a particle damping group, and hexagonal screws. Multiple unit structures are arranged between the inner and outer reinforcing rings of the integrated ring frame. Each unit structure is formed by rotating a damping cavity. The particle damping group is placed in the space enclosed by the damping cavity and the cover plate. The particle damping group consists of solid stainless steel spheres with large and small radii, which are placed tangentially in the cavity. The noise reduction ring as a whole is disassembled and replaced by splicing, which facilitates later maintenance and adjustment.

[0048] When vibrations and waves propagate along the shell structure, they are first periodically modulated by the axially arranged noise reduction rings, making it difficult for elastic waves within a specific frequency range to continue propagating effectively. After the elastic waves enter the noise reduction rings, multiple unit structures participate in the action within the integrated ring frame. The structural responses of different directions and forms transform the original form, weakening the propagation of vibrations and waves in the shell. Simultaneously, under vibration excitation, the particle damping group generates relative slippage, collision, and friction within the cavity. Particles of different radii correspond to different inertia and contact states, widening the effective band gap. During the transmission of vibrations and waves from the inner shell to the outer shell, they are decomposed and dispersed into multiple noise reduction rings, continuously attenuating. Through the synergistic effect of different noise reduction mechanisms, effective suppression of noise radiation from the shell structure is achieved.

[0049] like Figure 4As shown, the inner wall of the outer shell 1 and the outer wall of the inner shell 2 are respectively provided with periodically distributed outer shell connecting blocks 10 and inner shell connecting blocks 20. The connecting blocks are evenly distributed circumferentially along the shell and form multiple arrangement periods in the axial direction. In this embodiment of the invention, the connecting blocks are configured as a three-circumferential axial arrangement structure, that is, three sets of connecting blocks are arranged axially at corresponding positions of the outer shell and the inner shell, with six connecting blocks evenly arranged circumferentially in each circumferential direction, thereby forming a regular and symmetrical connection layout in the circumferential direction. The outer shell connecting blocks 10 and the inner shell connecting blocks 20 are respectively fixed to the inner surface of the corresponding outer shell 1 and the outer surface of the corresponding inner shell 2, and their positions correspond one-to-one with the installation position of the noise reduction ring 3, which is used to provide a stable connection interface for the noise reduction ring and create stable working conditions for the energy dissipation effect of the particle damping group in the noise reduction ring.

[0050] Figure 5 and Figure 6 The diagram shows a left-view perspective and an exploded view of the noise reduction ring provided in this embodiment. As shown, the noise reduction ring 3 consists of hexagonal screws 30, a cover plate 31, a particle damping group 32, and an integrated ring frame 33. The integrated ring frame 33, as the main structure of the noise reduction ring, is integrally formed using CNC machining or additive manufacturing processes, ensuring structural strength while maintaining good dimensional consistency and assembly precision. The particle damping group 32 is disposed in multiple damping cavities within the integrated ring frame 33 and is sealed and fixed by the cover plate 31. The cover plate 31 is detachably connected to the ring frame via hexagonal screws 30, thereby enabling the installation, replacement, and maintenance of the particle damping group. The noise reduction ring is assembled with the outer shell connecting block 10 and the inner shell connecting block 20 through the above structure, ensuring reliable connection while providing good ease of assembly and disassembly.

[0051] Figure 7 and Figure 8The diagram shows a partial exploded view and a partial perspective view of the left side of the noise reduction ring. As shown, the noise reduction ring 3 is mainly composed of hexagonal socket screws 30, a cover plate 31, a particle damping group 32, and an integrated annular frame 33. The cover plate 31 is positioned opposite the integrated annular frame 33, and the cover plate 31 has several threaded holes 310. The integrated annular frame 33 has threaded through holes 330 corresponding to its position. The hexagonal socket screws 30 pass through the threaded through holes 330 and the threaded holes 310 in sequence, thereby reliably fixing the cover plate 31 to the integrated annular frame 33, achieving the closed limiting of the particle damping group 32. The particle damping group 32 is composed of solid stainless steel spheres of different radii, with a radius ratio of 1:0.53 between the larger and smaller solid stainless steel spheres. The larger and smaller solid stainless steel spheres are staggered within each cavity, with 18 and 8 spheres respectively, and the particle filling rate of the entire cavity is 0.55. By using particles with different radii, the particle damping group exhibits different inertial response characteristics under structural vibration, participating in energy dissipation across multiple frequency ranges. Compared to particle damping with a single particle size, this dual-radius design is beneficial for extending the effective frequency band and improving the overall energy dissipation capacity of the noise reduction ring in the low-frequency and mid-low-frequency ranges.

[0052] Figure 9 and Figure 10 The diagram shows the outer and inner structural details of the integrated ring frame. As shown, the integrated ring frame 33 is a monolithically formed structure, with an outer reinforcing ring 331 and an inner reinforcing ring 335 on its outer and inner sides, respectively. The reinforcing rings improve the overall rigidity and structural stability of the noise reduction ring in its assembled state, while also providing reliable grooves for the connecting device 4. The outer reinforcing ring 331 has an outer groove 332, an outer connecting groove 333, and multiple circular through holes 334 in sequence. The inner reinforcing ring 335 has an inner groove 336, an inner connecting groove 337, and circular through holes 338. The outer connecting groove 333 and the inner connecting groove 337 are correspondingly connected to the outer shell connecting block 10 and the inner shell connecting block 20, achieving reliable assembly of the noise reduction ring with the double-layer shell.

[0053] Specifically, the outer groove 332 is a groove provided on the top and bottom surfaces of the outer reinforcing ring 331, the outer connecting groove 333 is a groove provided on the side of the outer reinforcing ring 331 and extends through the top and bottom surfaces of the outer groove 332, and the circular through hole 334 is provided on the outer groove 332.

[0054] The inner layer groove 336 is a groove provided on the top and bottom surfaces of the inner layer reinforcing ring 335. The inner layer connecting groove 337 is a groove provided on the side of the inner layer reinforcing ring 335 and passes through the inner layer groove 336 on the top and bottom surfaces. The circular through hole 338 is provided on the inner layer groove 336.

[0055] like Figure 11 and Figure 12 The diagram shown is an exploded view of the connecting device provided in an embodiment of the present invention. The connecting device 4 includes an outer connecting piece 40, an inner connecting piece 41, a cylindrical head screw 42, a flat washer 43, and a nut 44. The outer connecting piece 40 and the inner connecting piece 41 are respectively disposed at corresponding positions on the noise reduction ring and the outer shell and the inner shell, respectively, to achieve a detachable connection between the noise reduction ring and the double shell. Both the outer connecting piece 40 and the inner connecting piece 41 are provided with mounting holes for fasteners to pass through, the positions of which correspond to the circular through holes 334 and 338 on the integrated ring frame 33. During assembly, the cylindrical head screw 42 passes through the two outer connecting pieces 40 and the integrated ring frame 33, and a flat washer 43 is provided to improve the connection reliability. Finally, it is locked and fixed by the nut 44. The detachable connection between the noise reduction ring and the inner shell is set in the same way. Through the above connection method, the noise reduction ring can be stably installed between the outer shell and the inner shell, and can be disassembled and separated by the connecting device.

[0056] Figure 13 and Figure 14 This is a cross-sectional view and a partial cross-sectional structural diagram of the noise reduction device provided in an embodiment of the present invention. The cross-sectional structure clearly shows that the inner shell 2 and the outer shell 1 are connected and transitioned through multiple noise reduction rings 3. When the structure is subjected to internal excitation, vibrations and waves are transmitted outward from the inner shell 2 in the radial and axial directions, passing through the multiple noise reduction rings 3 disposed between the two shells along the propagation path. The superstructure units and particle damping groups inside the noise reduction rings modulate different frequency components step by step during vibration transmission, thereby achieving effective noise suppression. Simultaneously, the connecting device forms a stable and reliable mechanical connection between the inner and outer shells and the noise reduction rings, ensuring the reliability of the noise reduction performance and suitability for long-term service under complex operating conditions.

[0057] The working principle of a particle-damped noise suppression superstructure shell based on mode conversion function in the above-described embodiments of the invention includes:

[0058] During operation, vibrations generated by the internal equipment of the underwater vehicle first act on the inner shell and then propagate outwards. Multiple noise-reducing rings are placed between the inner and outer shells, thus modulating and attenuating vibrations and waves at multiple levels along their propagation path. These noise-reducing rings are arranged periodically along the shell's axial direction, creating a structural form with a distinct periodic characteristic. When vibrations and waves propagate within this periodic structure, multiple reflections and interferences occur between adjacent periodic units, producing a significant Bragg scattering effect. This scattering effectively suppresses elastic waves within a specific frequency range, making sustained propagation difficult. The center frequency of this bandgap is related to the periodic nature of the structure and the wave propagation characteristics. Furthermore, the bandgap position and width can be effectively adjusted by changing the structure's geometry, material parameters, and connection methods. Through this periodic arrangement, vibrations and waves are significantly attenuated before reaching the outer shell, thereby effectively reducing the radiated noise level of the shell structure.

[0059] The noise reduction ring comprises 12 unit structures, each formed by rotating individual damping cavities sequentially by 120°. This rotational arrangement introduces different spatial orientations, resulting in a non-mirror-symmetric spatial configuration for the overall noise reduction ring. Based on this structural characteristic, when vibrations and waves propagate along the shell structure and enter the noise reduction ring, the stress states and deformation modes in different structural units change, and the response is decomposed into multiple coupled components. This mode transition creates a transformation relationship between the vibration, radial, and local rotational responses, leading to repeated distribution of vibrations and waves among different response forms. This mode transition causes the propagation of vibrations and waves to no longer follow a single linear path, but rather propagate within the noise reduction ring in multiple coupled forms.

[0060] Furthermore, the particle damping group inside the noise reduction ring undergoes relative motion under external influence. This particle damping group consists of multiple solid stainless steel spheres, which roll, slide, and collide within the cavity, weakening the structure's response. Compared to particle damping groups with a single radius, the device of this invention employs alternating arrangements of particles with different radii within the same cavity, resulting in diverse characteristics. This alternating arrangement of particles with different radii enhances energy dissipation across multiple frequency ranges, thereby expanding the device's effective noise reduction bandwidth. Through the synergistic effect of the particle damping group and the noise reduction ring's mode-switching structure, the device of this invention achieves stable noise reduction performance across multiple frequency ranges.

[0061] like Figure 15 and Figure 16As shown, the acceleration and sound pressure level response curves of the noise reduction device provided in this embodiment of the invention are presented in the frequency range of 0 to 1000 Hz. In the model, the outer shell has a radius of 369.70 mm and a thickness of 10.80 mm; the inner shell has a radius of 183.62 mm and a thickness of 10.80 mm. The above response curves were obtained by applying a harmonic point excitation to the inner shell in air. The results in the figure show that the noise reduction device exhibits significant vibration and noise suppression effects in multiple frequency bands, with particularly outstanding effects in the frequency bands below 420 Hz, 500 Hz to 660 Hz, 730 Hz to 870 Hz, and above 920 Hz. The results indicate that the noise reduction device provided in this embodiment of the invention, through the combined effects of periodic structural characteristics, structural mode conversion, and particle damping energy dissipation mechanism, effectively suppresses the sound radiation of the shell structure over a wide frequency range. This result verifies the feasibility and effectiveness of the noise reduction device described in this embodiment of the invention in underwater vehicle noise reduction applications.

[0062] In summary, the noise reduction device proposed in this invention differs from traditional single-mechanism noise reduction schemes in both structural design and working mechanism. Based on a periodic structure, this device introduces a mode-switching effect within the structure and combines it with the energy dissipation characteristics of particle damping groups, enabling multiple suppression mechanisms to work synergistically within the same structure. By arranging the noise reduction ring between the inner and outer shells, vibrations and waves propagate from the inside out, passing through multiple structural units sequentially and undergoing continuous modulation and progressive attenuation, thereby effectively suppressing sound radiation over a wide frequency range. This structural form is suitable for complex operating conditions and provides an easily implementable solution for noise reduction design of the outer shell of underwater vehicles.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solution and working principle of the present invention, and do not constitute a limitation on the scope of protection of the present invention. Without departing from the overall concept of the present invention, those skilled in the art can adjust or modify the structure and parameters of the device according to specific application requirements. For example, the arrangement of the noise reduction device and the geometry of the structural units can be rationally designed according to actual dimensions and working conditions; the shape, size, and material of the particles used to form the particle damping group can also be changed accordingly. These equivalent substitutions or improvements should all be understood to fall within the scope of protection of the present invention.

[0064] Furthermore, the terminology used in this specification is for describing specific embodiments only and is not intended to limit the invention. Unless otherwise expressly stated, the singular form used herein should be understood to include the plural form; the term "comprising" indicates the presence of the described technical feature, but does not exclude the inclusion of other features or components. When a component is described as being connected to another component, the connection can be a direct connection or an indirect connection achieved through an intermediate structure, and the specific form of connection does not constitute a limitation on the invention. Those skilled in the art can understand and implement the invention based on this description without any inventive effort.

Claims

1. A particle-damped noise suppression superstructure device based on mode conversion function, characterized in that, include: The outer shell (1) and the inner shell (2) are coaxial and spaced apart in the radial direction; At least one noise reduction ring (3) is disposed between the outer shell (1) and the inner shell (2). The noise reduction ring (3) includes an integral ring frame (33) and a particle damping group (32) disposed in the internal space of the integral ring frame (33). A connecting device (4) is used to fix the noise reduction ring (3) to the outer shell (1) and the inner shell (2) respectively.

2. The particle-damped noise suppression superstructure device according to claim 1, characterized in that, The inner wall of the outer shell (1) is provided with a number of outer shell connecting blocks (10) along the circumferential and axial directions; the outer wall of the inner shell (2) is provided with a number of inner shell connecting blocks (20); the connecting device (4) cooperates with the outer shell connecting blocks (10) and the inner shell connecting blocks (20) to realize the detachable connection of the noise reduction ring (3).

3. The particle-damped noise suppression superstructure device according to claim 1 or 2, characterized in that, The integrated ring frame (33) has several structural units arranged in a circular direction. Each unit structure is formed by rotating several damping cavities. The damping cavities and the cover plate (31) form a closed space for accommodating the particle damping group (32).

4. The particle-damped noise suppression superstructure device according to claim 3, characterized in that, The integrated ring frame (33) contains several structural units arranged in a non-mirror symmetrical manner, which allows vibration and wave to propagate in several coupling forms. There are a total of 12 structural units, and the damping cavities in each structural unit are arranged in a spatial arrangement that rotates by 120° to form a mode conversion structure.

5. The particle-damped noise suppression superstructure device according to claim 3, characterized in that, The particle damping group (32) includes large particles with a first radius and small particles with a second radius; the large particles and the small particles are arranged alternately and tangentially in the damping cavity, and particles with different radii form different dynamic responses under external action, thus broadening the effective noise reduction frequency band.

6. The particle-damped noise suppression superstructure device according to claim 1, characterized in that, Multiple noise reduction rings (3) are arranged periodically at equal intervals along the axial direction of the inner shell (2) to generate the Bragg bandgap effect and suppress the propagation of vibration and wave.

7. The particle-damped noise suppression superstructure device according to claim 2, characterized in that, The outer and inner sides of the integrated ring frame (33) are respectively provided with an outer reinforcing ring (331) and an inner reinforcing ring (335); the outer reinforcing ring (331) is provided with an outer connecting groove (333), and the inner reinforcing ring (335) is provided with an inner connecting groove (337); the connecting piece of the connecting device (4) is embedded in the connecting groove and is connected to the outer shell connecting block (10) and the inner shell connecting block (20) by fasteners.

8. The particle-damped noise suppression superstructure device according to claim 1, characterized in that, The device has a sound radiation suppression effect in the frequency bands below 420Hz, 500Hz to 660Hz, 730Hz to 870Hz, and above 920Hz.

9. The particle-damped noise suppression superstructure device according to claim 1, characterized in that, The integrated ring frame (33) is integrally formed by CNC machining or additive manufacturing process, and the outer shell (1), inner shell (2) and noise reduction ring (3) are made of stainless steel.

10. An application of the particle-damped noise suppression superstructure device according to any one of claims 1-9, characterized in that, External hull structure used for underwater vehicles to reduce noise radiation generated during operation.

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