Mute device for underwater sound absorption

Abstract

The invention discloses an underwater sound absorption silencing device which comprises a resonance structure, a sound absorption structure arranged above the resonance structure and a silencing structure arranged at the bottom of the resonance structure, the sound absorption structure comprises a protection frame and a sound absorption piece arranged on the inner side of the protection frame, and a sound absorption plate is arranged on the protection frame; a plurality of conical sound absorption holes are formed in the sound absorption plate, and the sound absorption piece is provided with multiple holes; the resonant structure comprises a plurality of resonant cavities; a sound absorption pipe is arranged on each resonant cavity; the sound absorption pipes are connected with the bottom of the protection frame, and the sound absorption pipes are different and used for optimizing the sound absorption effect; the noise elimination structure comprises a plurality of noise elimination units and noise elimination cores arranged in the dissipation units. The silencing units are arranged at the bottom of the resonant cavity in an array mode, a plurality of silencing channels are formed in the silencing core, and the silencing channels are arranged in a cross-linking mode; therefore, the impact resistance of the device is improved, and the service life of the device is prolonged.

Description

Technical Field

[0001] The present invention relates to a sound - quieting device for underwater sound absorption, and particularly to a sound - quieting device for underwater sound absorption. Background Art

[0002] With the wide application of underwater equipment (such as submarines, underwater drones, sub - sea exploration equipment, etc.), the demand for underwater acoustic stealth technology is increasing day by day. Underwater acoustic stealth technology not only requires effective absorption of sound waves emitted by the target, but also excellent shock - resistance performance and environmental adaptability to cope with complex underwater environments. Traditional underwater sound - absorbing materials usually adopt a single porous structure or resonance cavity design. Although they can absorb sound waves to a certain extent, their sound - absorbing effect in the low - frequency range is poor, and their shock - resistance performance and durability are insufficient. In addition, when traditional materials are subjected to water flow impact or sound wave impact, stress concentration is likely to occur, resulting in local structural damage, and thus affecting the service life of the device.

[0003] To solve the above problems, in recent years, researchers have begun to explore new sound - absorbing structures and materials. Materials with negative Poisson's ratio have attracted much attention due to their unique mechanical properties (i.e., lateral expansion when stretched and lateral contraction when compressed). Such materials can absorb more energy through structural deformation, disperse stress, and avoid local stress concentration, thus significantly improving the shock - resistance performance. Summary of the Invention

[0004] The present invention overcomes the deficiencies of the prior art and provides a sound - quieting device for underwater sound absorption.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A sound - quieting device for underwater sound absorption, comprising: a resonance structure, a sound - absorbing structure disposed above the resonance structure, and a noise - eliminating structure disposed at the bottom of the resonance structure.

[0006] The sound - absorbing structure includes: a protective frame, a sound - absorbing member disposed inside the protective frame, and a sound - absorbing plate disposed on the protective frame; a plurality of conical sound - absorbing holes are formed on the sound - absorbing plate, and the sound - absorbing member is porous.

[0007] The resonance structure includes: a plurality of resonance cavities; an absorption tube is disposed on each resonance cavity; the absorption tube is connected to the bottom of the protective frame, and each absorption tube is different, and the absorption tube is used to optimize the sound - absorbing effect.

[0008] The noise - eliminating structure includes: a plurality of noise - eliminating units, and a noise - eliminating core disposed inside the dissipation unit; the noise - eliminating units are arranged in an array at the bottom of the resonance cavity, a plurality of noise - eliminating channels are formed inside the noise - eliminating core, and the plurality of noise - eliminating channels are cross - linked.

[0009] In a preferred embodiment of the present invention, a plurality of protective frames are arranged in an array. The cross-section of the protective frame is concave octagonal. The protective frame is bent towards the center of the protective frame both in the horizontal direction and the vertical direction, and the bending radius at the bending point is 5-20 mm. The protective frame is used to improve the impact resistance of the device.

[0010] In a preferred embodiment of the present invention, the sound-absorbing plate is arranged on the side away from the resonance structure, and the smaller hole end of the conical sound-absorbing hole is arranged on the side close to the sound-absorbing member.

[0011] In a preferred embodiment of the present invention, the surface and the interior of the sound-absorbing member are porous, and the sound-absorbing member is used for preliminary absorption of sound waves.

[0012] In a preferred embodiment of the present invention, a resonance cavity is correspondingly arranged at the bottom of each protective frame. A plurality of resonance chambers are arranged in the resonance cavity, and each resonance chamber is communicated with the protective frame through a sound-absorbing tube.

[0013] In a preferred embodiment of the present invention, the lengths and radii of the sound-absorbing tubes are different, and the longer part of the longer sound-absorbing tube extends into the resonance cavity.

[0014] In a preferred embodiment of the present invention, a resonance cavity is correspondingly arranged at the bottom of one protective frame. An arc-shaped baffle is arranged at the bottom outside the protective frame, and the bottom of the baffle contacts the resonance cavity.

[0015] In a preferred embodiment of the present invention, the outer surface of the dissipation unit is cross-shaped both in the horizontal vertical plane and the longitudinal vertical plane. The curvature of the outer surface of the dissipation unit is greater than zero, and the dissipation unit is used to reduce the influence of biological attachment.

[0016] In a preferred embodiment of the present invention, the dissipation unit is hollow. The noise elimination core is cross-shaped both in the horizontal vertical plane and the longitudinal vertical plane, and noise elimination grooves are arranged on six surfaces of the noise elimination core.

[0017] In a preferred embodiment of the present invention, a noise elimination channel is opened at the noise elimination groove at the top of the noise elimination core, and the dissipation channel is bent and is in a communicating state in the noise elimination core.

[0018] The present invention solves the defects in the background art, and the present invention has the following beneficial effects:

[0019] (1) The present invention provides a silent device for underwater sound absorption. Through the synergistic effect of the conical sound absorption holes and the gradient density foam in the sound absorption structure, the efficient guidance and preliminary absorption of sound waves are achieved. The gradually changing cross-section design of the conical sound absorption holes can effectively guide the sound waves into the device, reducing surface reflection. The gradient density foam, through its porous characteristics and density gradient distribution, realizes the preliminary absorption of sound waves. The low-density foam is located on the surface layer to absorb higher-frequency sound waves, and the high-density foam is located inside to absorb lower-frequency sound waves. This design enables the sound waves to be gradually absorbed during propagation, avoiding energy concentration and significantly improving the sound absorption efficiency.

[0020] (2) The present invention provides a silent device for underwater sound absorption. Through the local resonance and coherent coupling mechanisms of the sound absorption tube and the resonance cavity in the resonance structure, the efficient absorption of broadband sound waves is achieved. By setting the sound absorption tubes and resonance cavities with different geometric parameters, different frequency ranges can be covered, forming multiple resonance peaks. The coherent coupling effect between multiple resonance cavities further broadens the sound absorption bandwidth, merging multiple narrowband resonance peaks into a broadband multi-peak and deep-valley sound absorption effect, significantly improving the sound absorption performance, especially the sound absorption effect in the low-frequency range.

[0021] (3) The present invention provides a silent device for underwater sound absorption. Through the sound absorption groove and the curved sound absorption channel in the sound insulation structure, by extending the propagation path of the sound waves and increasing the contact time between the sound waves and the material surface, the final absorption and energy dissipation of the residual sound waves are achieved. By setting the curved channel to induce the sound waves to generate rotational flow and eddy currents, the viscous loss and thermoelastic loss are enhanced. The multi-directional sound absorption design of the sound absorption core and the curved sound absorption channel significantly enhance the energy dissipation effect, causing the sound waves to undergo multiple reflections and refractions when passing through the sound absorption channel, further increasing the energy loss.

[0022] (4) The present invention provides a silent device for underwater sound absorption. By setting a protective frame in the shape of a negative Poisson's ratio structure, through its unique geometric design and mechanical properties, the impact resistance of the device is significantly enhanced. When subjected to water flow or sound wave impact, the frame absorbs energy through the negative Poisson's ratio effect, avoiding stress concentration. The large-angle bending radius forms a smooth arc-shaped surface design, further reducing the stress concentration phenomenon, enabling the stress to be evenly distributed in the structure and reducing the risk of local damage. This not only improves the impact resistance of the device but also extends its service life.

[0023] (5) The present invention provides a silent device for underwater sound absorption. By adopting a large bending radius at the bending part of the protective frame to form a smooth arc-shaped curved surface design, the hydrodynamic performance is optimized, enabling the water flow to pass smoothly through the surface of the device, reducing the generation of turbulence and eddies. The reduction of turbulence avoids the local non-uniform distribution of oxygen concentration in the fluid, thereby suppressing the formation of oxygen concentration difference cells and reducing electrochemical corrosion. At the same time, the uniform distribution of the flow velocity reduces the damage of the passive film, further delaying the corrosion process. Moreover, the sound absorption unit adopts a cross-shaped curved surface design, and the curvature of its outer surface is greater than zero, forming a streamlined profile. This design reduces the retention of water flow on the surface, avoids the formation of local low-velocity areas, suppresses the microenvironment required for biological attachment, and at the same time, the smooth surface reduces the enrichment of organic matter and microorganisms, cutting off the material basis for biological attachment. In this way, the probability of biological attachment is further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0025] Figure 1 is a three-dimensional structure diagram of a preferred embodiment of the present invention;

[0026] Figure 2 is a schematic cross-sectional view of the sound absorption structure of a preferred embodiment of the present invention;

[0027] Figure 3 is a schematic cross-sectional structure diagram of the sound absorption unit of a preferred embodiment of the present invention;

[0028] In the figure: 1, sound absorption structure; 2, resonance structure; 3, sound absorption structure; 4, protective frame; 5, sound absorption plate; 6, sound absorption hole; 7, sound absorption member; 8, resonance cavity; 9, sound absorption tube; 10, sound absorption unit; 11, sound absorption core; 12, sound absorption channel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be practiced in other ways than those specifically described herein, and thus, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0031] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0032] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood through specific circumstances.

[0033] As shown in the figure, a silent device for underwater sound absorption includes: a resonance structure, a sound absorption structure disposed above the resonance structure, and a noise elimination structure disposed at the bottom of the resonance structure.

[0034] It should be noted that the present application is mainly applicable to underwater sound absorption and silence. The device is mainly centered on the sound - emitting object and disposed around the sound - emitting object, finely absorbs the sound waves emitted by the sound - emitting object, and eliminates the sound to achieve acoustic silence. The side of the device close to the sound - emitting object is the inner side, and the side far from the sound - emitting object is the outer side, that is, the absorption structure is disposed on the inner side, the noise elimination structure is disposed on the outer side, and the resonance structure is disposed between the absorption structure and the noise elimination structure.

[0035] The sound absorption structure includes a protective frame, a sound absorption member disposed inside the protective frame, and a sound absorption plate disposed on the protective frame; a plurality of conical sound absorption holes are formed on the sound absorption plate, and the sound absorption member is provided with pores.

[0036] In a preferred embodiment of the present invention, a plurality of protective frames are arranged in an array. The cross-section of the protective frame is in the shape of an inwardly concave octagon. The protective frame is bent towards the center of the protective frame both in the horizontal direction and in the vertical direction, and the bending radius at the bending part is 5-20 mm. The protective frame is used to improve the impact resistance of the device.

[0037] It should be noted that a plurality of protective frames are provided and arranged in an array. The protective frame is integrally printed and formed by 3D pressing technology, and the cross-section is in the shape of an inwardly concave octagon similar to a shape that depresses towards the origin with its center point as the origin. That is, the protective frame bends towards the center of the protective frame in the horizontal direction. At the same time, in the vertical direction of the protective frame, the protective frame is concave towards the center of the protective frame in a V shape, so that the protective frame forms a frame with a negative Poisson's ratio. Moreover, a large bending angle is adopted at the bending part of the protective frame to form a smooth arc-shaped surface. When the protective frame with a negative Poisson's ratio is stretched or compressed, that is, when it is impacted by water flow and sound waves, the dimension perpendicular to the stretching direction will expand (instead of shrinking); when it is compressed, the dimension perpendicular to the compression direction will shrink (instead of expanding). In this way, when the material is impacted, it can absorb more energy through structural deformation, and at the same time disperse stress to avoid local stress concentration. When an impact force acts on the negative Poisson's ratio frame, the concave geometric shape (i.e., the inwardly concave octagon or V shape) of the frame will bend and deform, thereby absorbing the impact energy to cope with multi-directional impacts. The protective frame with a negative Poisson's ratio makes the stress evenly distributed in the structure instead of concentrating at a certain point, thereby reducing the risk of local damage. Through the bending deformation of the structure and the negative Poisson's ratio effect, the impact energy is converted into elastic deformation energy and plastic deformation energy, significantly improving the energy absorption capacity, so as to effectively resist the impact of sound waves and water flow and protect the internal structure from damage. At the same time, at the bent part of the protective frame, a large-angle bending is also adopted to form a smooth arc-shaped surface, so as to avoid the situation where the stress will increase significantly at the sharp edges or corners, resulting in the easy occurrence of crack initiation and propagation of the material. The large-angle bending radius forms a smooth arc-shaped surface design, eliminating the sharp edges and making the stress evenly distributed on the surface, reducing the stress concentration phenomenon.

[0038] Moreover, the large bending radius forms a smooth arc-shaped surface, reducing the turbulence and eddy currents when water flows through, thereby avoiding the increase in local flow velocity caused by turbulence and eddy currents, accelerating the scouring effect of the fluid on the surface of the protection frame, and thus exacerbating the corrosion situation. Also, due to the uneven distribution of oxygen concentration in the fluid caused by turbulence and eddy currents, the long-term persistence of this situation will form an oxygen concentration difference cell, resulting in electrochemical corrosion. Therefore, the reduction of turbulence and eddy currents also reduces the electrochemical corrosion on the surface of the protection frame. In the formation area of turbulence and eddy currents, local enrichment of nutrients will occur, providing material survival conditions for organisms. Moreover, a low-flow velocity area will form on the surface of the eddy current, making it easier for organisms to attach to the surface of objects in this area, that is, the surface of the protection frame. The bending part of the anti-slip frame is set with a smooth arc, enabling the water flow to smoothly transition on the surface of the protection frame, reducing the generation of turbulence and eddy currents, and thus avoiding providing favorable conditions for the attachment of organisms, thereby reducing the attachment of organisms.

[0039] In the present invention, the sound absorption panel is arranged on the side away from the resonance structure, and the smaller-hole end of the conical sound absorption hole is arranged on the side close to the sound absorption member; the surface and the interior of the sound absorption member are arranged in a porous manner, and the sound absorption member is used for initially absorbing sound waves.

[0040] It should be noted that the sound absorption panel is arranged inside the protection frame, that is, on the side away from the resonance structure. A conical sound absorption hole is opened on the sound absorption panel to guide sound waves into the device. The inside of the frame is filled with a sound absorption member, and the sound absorption member is specifically foam. The density of the foam is set in a gradient manner to achieve efficient guidance and initial absorption of sound waves. The gradient cross-section design of the conical sound absorption hole can effectively guide sound waves into the device, reducing the reflection of sound waves on the surface. The entrance of the conical hole is larger and the exit is smaller, which can match the wavelength characteristics of sound waves and improve the incident efficiency of sound waves. The geometric shape of the conical hole can achieve a gradient transition of acoustic impedance, increasing the energy loss of sound waves when entering the device. When sound waves pass through the conical hole, a rotational flow will be generated, forming eddy currents and increasing viscous losses, thereby converting the sound wave energy into heat energy.

[0041] The porous characteristics of the foam material can absorb sound wave energy through viscous losses and thermoelastic losses. Moreover, the gradient density design makes the density of the foam gradually increase from the surface layer to the inside, forming a gradient change in acoustic impedance and reducing sound wave reflection. The low-density foam is located on the surface layer and can effectively absorb higher-frequency sound waves; the high-density foam is located inside and can absorb lower-frequency sound waves. This gradient design enables sound waves to be gradually absorbed during propagation, avoiding energy concentration. The porous structure of the foam increases the contact area between sound waves and the material surface, converting sound wave energy into heat energy through friction and vibration. The gradient density design further optimizes the energy dissipation path and improves the sound absorption efficiency.

[0042] When working in this way, the conical sound-absorbing holes on the surface efficiently guide sound waves into the interior of the device, reducing surface reflection. The gradient-density foam inside the negative Poisson's ratio-like protective frame initially absorbs the sound waves, reducing the sound wave energy. The combined action of the conical sound-absorbing holes and the gradient-density foam forms a multi-stage energy dissipation path, improving the sound absorption efficiency. After passing through the conical holes, the sound waves enter the foam material and further absorb energy through viscous loss and thermoelastic loss. The combination of the conical sound-absorbing holes and the gradient-density foam can cover the sound absorption requirements in a wide frequency range. Through the collaborative design of the conical sound-absorbing holes and the gradient-density foam, the efficient guidance and initial absorption of sound waves are achieved, significantly improving the sound absorption performance. The design of the gradient-density foam enables the device to cover the sound absorption requirements in a wide frequency range, and the negative Poisson's ratio frame provides excellent impact resistance and structural strength. At the same time, the overall light weight is achieved through lightweight materials (such as foam).

[0043] The resonance structure includes: a number of resonance cavities; an acoustic absorption tube is provided on each resonance cavity; the acoustic absorption tube is connected to the bottom of the protective frame, and each acoustic absorption tube is different, and the acoustic absorption tube is used to optimize the sound absorption effect;

[0044] In a preferred embodiment of the present invention, the resonance cavities are correspondingly arranged at the bottom of each protective frame, and a number of resonance chambers are arranged in the resonance cavities, and each resonance chamber is communicated with the protective frame through an acoustic absorption tube.

[0045] In a preferred embodiment of the present invention, the lengths and radii of the acoustic absorption tubes are different, and the longer part of the longer acoustic absorption tube extends into the interior of the resonance cavity.

[0046] In a preferred embodiment of the present invention, a resonance cavity is correspondingly arranged at the bottom of one protective frame, and an arc-shaped baffle is arranged at the outer bottom of the protective frame, and the bottom of the baffle is in contact with the resonance cavity.

[0047] It should be noted that a resonance cavity is provided at the bottom of each protective frame. A number of resonance chambers are provided inside the resonance cavity. An acoustic absorption tube is provided in each resonance chamber, and the length and radius of each acoustic absorption tube are different. In this way, the sound waves that are not completely dissipated within the protective frame are absorbed by different acoustic absorption tubes, so as to achieve low-frequency broadband absorption of sound waves of different frequencies. Since the lengths and radii of each acoustic absorption tube are different, the resonance frequencies and resonance peaks of the resonance cavity are also different. The absorption of sound waves in a wide frequency range is achieved through the coherent coupling effect between each cavity. The geometric parameters (length and radius) of the acoustic absorption tube determine its acoustic impedance characteristics. By adjusting the parameters of the acoustic absorption tube, the resonance frequency and resonance peak of the resonance cavity can be adjusted. Acoustic absorption tubes and resonance cavities with different geometric parameters can cover different frequency ranges, and are coupled to achieve broadband acoustic absorption. Coherent coupling effects are generated through acoustic interference between multiple resonance cavities to form broadband acoustic absorption peaks. Coherent coupling can combine multiple narrowband resonance peaks into one broadband acoustic absorption peak, improving the acoustic absorption efficiency. In this way, through the synergistic effect of local resonance and coherent coupling, the resonance structure can cover the acoustic absorption requirements in a wide frequency range, especially the effective absorption of low-frequency sound waves. By adjusting the geometric parameters of the acoustic absorption tube, impedance matching with sound waves of different frequencies is achieved, reducing reflection loss and improving the acoustic absorption efficiency.

[0048] The sound absorption structure includes: a number of sound absorption units, and a sound absorption core provided inside the dissipation unit; the sound absorption units are arranged in an array at the bottom of the resonance cavity, and a number of sound absorption channels are opened inside the sound absorption core, and the number of sound absorption channels are cross-linked.

[0049] In a preferred embodiment of the present invention, the outer surface of the dissipation unit is cross-shaped both in the horizontal vertical plane and in the longitudinal vertical plane, and the curvature of the outer surface of the dissipation unit is greater than zero. The dissipation unit is used to reduce the influence of biological attachment; the dissipation unit is hollow, the sound absorption core is cross-shaped both in the horizontal vertical plane and in the longitudinal vertical plane, and sound absorption grooves are provided on all six surfaces of the sound absorption core; the sound absorption channels are opened at the sound absorption grooves at the top of the sound absorption core, and the dissipation channels are curved and are connected in the sound absorption core.

[0050] It should be noted that the outer surface of the sound absorption unit is cross-shaped both in the horizontal and longitudinal vertical planes, and the curvature is greater than zero. This smooth curved surface design can reduce biological attachment. The streamlined design of the cross-shaped curved surface enables the water flow to pass smoothly, reducing the generation of turbulence and eddies, thereby reducing the risk of biological attachment. Moreover, the smooth curved surface design reduces the scouring effect of the fluid on the surface, reducing the corrosion rate. The uniform stress distribution of the cross-shaped curved surface reduces local stress concentration and enhances the durability of the structure. The sound absorption unit is hollow, which can achieve lightweight while ensuring the structural strength and is suitable for underwater applications.

[0051] The hollow structure can enhance the energy dissipation effect through sound wave reflection and internal resonance. The sound-absorbing core is in a cross shape on both the horizontal and vertical planes in the longitudinal and transverse directions, and can absorb sound wave energy in multiple directions. The cross-shaped design increases the contact area between the sound wave and the sound-absorbing core, improving the sound absorption efficiency. Sound-absorbing grooves are provided on all six faces of the sound-absorbing core. These sound-absorbing grooves can guide the sound wave into the interior of the sound-absorbing core. The sound-absorbing channels are arranged in a curved shape and are distributed in a connected state within the sound-absorbing core. This design can extend the propagation path of the sound wave, increasing the contact time between the sound wave and the material surface. The curved channels can induce the sound wave to generate rotational flow and vortices, enhancing the viscous loss and thermoelastic loss. The cross-shaped curved surface design of the sound-absorbing unit guides the sound wave into the sound-absorbing core, reducing surface reflection. The sound-absorbing grooves and curved sound-absorbing channels in the sound-absorbing core further guide the propagation of the sound wave and absorb the sound wave energy through viscous loss and thermoelastic loss. The multi-directional sound absorption design of the sound-absorbing core and the curved sound-absorbing channels can significantly enhance the energy dissipation effect. When the sound wave passes through the sound-absorbing channel, multiple reflections and refractions will occur, thereby increasing the energy loss. Through the cross-shaped curved surface design of the sound-absorbing unit and the multi-directional sound absorption mechanism of the sound-absorbing core, the efficient guidance and absorption of the sound wave are realized. The design of the curved sound-absorbing channels and sound-absorbing grooves significantly enhances the viscous loss and thermoelastic loss, converting the sound wave energy into heat energy. The smooth cross-shaped curved surface design of the sound-absorbing unit reduces the possibility of biological attachment and enhances the environmental adaptability of the device. The hollow structure of the sound-absorbing unit and the geometric design of the sound-absorbing core can disperse the impact stress and enhance the overall impact resistance.

[0052] Example 1:

[0053] This example provides a silent device for underwater sound absorption, which is mainly used for efficiently absorbing and silencing the sound waves generated by underwater sound-emitting objects (such as submarines, underwater equipment, etc.) to achieve an acoustic silent effect. The device is centered around the sound-emitting object and is arranged around it, including a sound-absorbing structure, a resonance structure, and a sound-absorbing structure, which are located on the inner side, the middle layer, and the outer side of the device respectively. Through the synergistic effect of the multi-layer structure, the device can achieve efficient absorption of broadband sound waves and at the same time has excellent impact resistance and environmental adaptability.

[0054] The sound-absorbing structure is located inside the device, close to the sound-generating object, and is mainly used for the preliminary absorption and guidance of sound waves. The protective frame adopts a negative Poisson's ratio structure, with an inwardly concave octagonal cross-section, bending towards the center both horizontally and vertically, and the bending radius at the bending point is 13 mm, thus forming a smooth arc-shaped surface design. The protective frame is integrally formed by 3D printing technology and has excellent impact resistance. When impacted by water flow or sound waves, the frame absorbs energy through the negative Poisson's ratio effect, avoiding stress concentration. The large bending radius of 13 mm forms a smooth arc-shaped surface design, reducing the generation of turbulence and eddies, and lowering the risks of corrosion and biofouling. The sound-absorbing plate is arranged inside the protective frame, and conical sound-absorbing holes are opened on the plate. The entrance of the conical hole is larger and the exit is smaller, which can effectively guide sound waves into the device interior, reducing surface reflection. The geometric shape of the conical hole realizes the gradient transition of acoustic impedance, optimizing the incident efficiency of sound waves. The sound-absorbing component is filled inside the protective frame and uses gradient density foam material. The density of the foam gradually increases from the surface layer to the interior, forming a gradient change in acoustic impedance and reducing sound wave reflection. The low-density foam is located on the surface layer to absorb higher-frequency sound waves; the high-density foam is located inside to absorb lower-frequency sound waves, thereby achieving the efficient guidance and preliminary absorption of sound waves.

[0055] The resonance structure is located between the sound-absorbing structure and the sound-damping structure, and is mainly used for low-frequency broadband sound absorption of sound waves. When sound waves pass through the sound-absorbing tube, viscous loss and thermoelastic loss occur, converting the sound wave energy into heat energy, thereby achieving the absorption and dissipation of sound waves. A resonance cavity is provided at the bottom of each protective frame, and the interior of the cavity is divided into multiple resonance chambers. Each resonance chamber is connected to the protective frame through a sound-absorbing tube. The lengths and radii of the sound-absorbing tubes are different to achieve the absorption of sound waves of different frequencies. The geometric parameters (length and radius) of the sound-absorbing tube determine its acoustic impedance characteristics. The coherent coupling of absorption cavities with different impedances realizes the broadband absorption of low-frequency sound waves, significantly improving the sound absorption efficiency.

[0056] The sound-damping structure is located outside the device, mainly used for the final absorption and energy dissipation of residual sound waves. The sound-damping units are arranged in an array at the bottom of the resonance cavity. The outer surface is cross-shaped in both the horizontal and vertical planes of the vertical plane, and the curvature is greater than zero. The cross-shaped surface design reduces the generation of turbulence and eddies, and lowers the risks of corrosion and biofouling. The sound-damping units are hollow, which can achieve lightweight while ensuring structural strength. The sound-damping core is located inside the sound-damping unit, arranged in a cross shape, and sound-damping grooves are opened on all six surfaces. Curved sound-damping channels are provided in the sound-damping grooves, and the channels are distributed in a connected manner inside the sound-damping core, which can extend the propagation path of sound waves, increase energy dissipation, and the curved channels induce the sound waves to generate rotational flow and eddies, enhancing viscous loss and thermoelastic loss.

[0057] During operation, sound waves first enter the interior of the device through the conical sound-absorbing holes on the sound-absorbing panel to reduce surface reflection. The gradient-density foam within the sound-absorbing component initially absorbs the sound waves, reducing the sound wave energy. After the sound waves enter the resonance structure, they undergo local resonance with the sound-absorbing tubes and resonance cavities of different geometric parameters to achieve broadband sound absorption. The coherent coupling effect between multiple resonance cavities further broadens the sound absorption bandwidth. The residual sound waves enter the sound-absorbing structure and are finally absorbed through the sound-absorbing grooves and curved sound-absorbing channels. The sound waves undergo multiple reflections and refractions within the sound-absorbing core, increasing the energy loss until all the sound wave energy is consumed.

[0058] Experiment 1:

[0059] Based on Example 1, the bending radius of the protective frame in Example 1 was changed respectively. Example 1 was used as the control group. The devices of the present application with different radii were respectively placed in a corrosion chamber to simulate the underwater environment for corrosion test to detect the corrosion rate of the installation system, and a drop hammer impact experiment was conducted to detect the energy absorption efficiency of the device. The temperature in the corrosion chamber was 35°C, the salt spray solution was a 5% sodium chloride solution, the pH of the salt spray solution should be maintained at 6.5, and the time was 24 h. During the experiment, the solution was stirred to simulate the waves under different wave speeds and waveforms to simulate the corrosion situation in the actual marine environment. The drop hammer impact experiment was specifically carried out by lifting the drop hammer to a height of 1 m through a lifting mechanism, releasing the drop hammer to freely fall and impact the protective frame, and recording various data in the experiment. According to E = mgh, where E is the impact energy, m is the mass of the drop hammer, g is the acceleration due to gravity, and h is the falling height, the impact energy was calculated, and according to where η is the energy absorption efficiency, E 吸收 is the absorbed energy, E 总 is the total impact energy, and the energy absorption efficiency was calculated. The stress concentration coefficient was obtained by preparing a protective frame with geometrically discontinuous holes, using a drop hammer impact testing machine to conduct an impact test on the specimen, recording the force and displacement data during the impact process, and according to where K t is the stress concentration coefficient, σ 最大 is the local maximum compressive stress, σ 名义 is the nominal stress, and the energy absorption efficiency and the stress concentration coefficient were calculated accordingly. The specific results are shown in Table 1

[0060] Table 1

[0061]

[0062] As can be seen from the data in the table, when the radius of curvature is 13 mm, the energy absorption efficiency can reach more than 80%, and the corrosion rate is below 0.1 mm / year. By preparing the protective frame in the form of an arc-shaped surface, the turbulence is reduced. The reduction of turbulence avoids the local non-uniform distribution of the oxygen concentration in the fluid, thereby inhibiting the formation of oxygen concentration cells. Oxygen concentration cells are the main inducement of electrochemical corrosion, and their formation will lead to the acceleration of local corrosion. By forming a bending angle with a radius of curvature of 13 mm through large-angle bending, the surface of the device can maintain a uniform oxygen concentration distribution, reducing the risk of electrochemical corrosion. At the same time, when the radius of curvature is 13 mm, the energy absorption efficiency can reach more than 80%, and the stress concentration coefficient is controlled at 1.1. This design can absorb the energy of acoustic shock while avoiding material fatigue and damage caused by local stress concentration. Thus, when the protective frame is impacted by sound waves and water waves, it expands laterally and contracts laterally when compressed. This characteristic enables it to absorb more energy through structural deformation when being impacted.

[0063] Based on the ideal embodiments of the present invention as an inspiration, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. An underwater sound-absorbing and mute device, comprising: A resonant structure, a sound absorbing structure arranged above the resonant structure, and a sound absorbing structure arranged at the bottom of the resonant structure, characterized in that: The sound absorbing structure comprises a protective frame, a sound absorbing member arranged inside the protective frame, a sound absorbing plate arranged on the protective frame; a plurality of conical sound absorbing holes are opened on the sound absorbing plate, and the sound absorbing member is arranged in a multi-hole manner; The resonance structure comprises: a plurality of resonance cavities; each of the resonance cavities is provided with a sound absorbing tube; the sound absorbing tube is connected to the bottom of the protection frame, each of the sound absorbing tubes is different, and the sound absorbing tube is used to optimize the sound absorption effect; The noise reduction structure includes: a plurality of noise reduction units, and a noise reduction core arranged inside the dissipation unit; the noise reduction units are arranged in an array at the bottom of the resonance cavity, and a plurality of noise reduction channels are opened inside the noise reduction core, and the plurality of noise reduction channels are arranged in a cross-linked manner.

2. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The protective frame is provided with several arranged in an array, and the cross-section of the protective frame is a concave octagon. The protective frame is bent toward the center of the protective frame in the horizontal direction and the vertical direction, and the bending radius of the bending part is 5-20mm. The protective frame is used to improve the impact resistance of the device.

3. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The sound absorbing plate is arranged at a side away from the resonance structure, and the end of the tapered sound absorbing hole with a smaller hole is arranged at a side close to the sound absorbing member.

4. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The surface and interior of the sound absorbing member are porous, and the sound absorbing member is used for initially absorbing sound waves.

5. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The resonance cavity is correspondingly arranged at the bottom of each of the protection frames, and a plurality of resonance chambers are arranged in the resonance cavity, and each of the resonance chambers is connected to the protection frame through the sound absorption pipe.

6. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The sound absorbing tubes have different lengths and radii, and the longer portion of the longer sound absorbing tube extends into the interior of the resonance cavity.

7. The underwater sound absorbing and silencing device according to claim 1, characterized in that: A resonance cavity is correspondingly arranged at the bottom of one of the protection frames, and an arc-shaped baffle is arranged at the bottom of the outer side of the protection frame, and the bottom of the baffle is in contact with the resonance cavity.

8. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The outer surface of the dissipation unit is arranged in a cross shape on the transverse vertical plane and the longitudinal vertical plane, and the curvature of the outer surface of the dissipation unit is greater than zero. The dissipation unit is used to reduce the influence of biological attachment.

9. The underwater sound absorbing and silencing device according to claim 1, characterized in that: The dissipation unit is hollow, the muffler core is cross-shaped on both the transverse vertical plane and the longitudinal vertical plane, and muffler grooves are provided on the six surfaces of the muffler core.

10. An underwater sound-absorbing and silencing device according to claim 9, characterized in that: The muffler channel is opened at the muffler groove on the top of the muffler core, and the dissipation channel is arranged in a curved shape and is arranged in a connected shape in the muffler core.

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