A composite material framework for a curved thin-shell receiving array and a manufacturing method and application thereof

Abstract

This invention discloses a composite material frame for a curved thin-shell receiver array. The composite material frame includes a support frame with multiple array element mounting slots. Each array element mounting slot has array element wiring holes. Multiple rubber through holes are evenly arranged on the support frame outside the array element mounting slots. The support frame has multiple transition parts on its outer side, each transition part having a frame mounting hole, and connectors are installed on the frame mounting holes. The manufacturing method of this composite material frame includes: S1, manufacturing a copper mesh shielding layer; S2, manufacturing the composite material frame; S3, manufacturing mounting accessories. The invention also discloses a method for applying this composite material frame to manufacture a curved thin-shell receiver array, including: S1, installing hydrophones and arranging wires; S2, potting and shaping with adhesive; S3, assembling mounting accessories. The advantages of this invention are: reasonable overall design, light weight, high strength, convenient installation and use, good sound transmission performance, high positioning accuracy, dense array element distribution, good vibration resistance, and safety and reliability.

Description

Technical Field

[0001] This invention belongs to the field of underwater acoustic transducer technology, and in particular to a composite material skeleton for a curved thin-shell receiving array, its manufacturing method, and its application. Background Technology

[0002] With the deepening of concepts in ocean development and underwater warfare, underwater unmanned platforms have become key underwater equipment due to their superior stealth, maneuverability, and cost-effectiveness. Sonar systems, serving as the "eyes and ears" of underwater unmanned platforms for perceiving the underwater environment, directly determine the platform's survivability and mission execution capabilities.

[0003] Currently, underwater unmanned platforms mainly carry three types of sonar systems: bow array, flank array, and stern towed array. Existing technologies are primarily based on rigid metal frames. For example, bow arrays based on rigid metal frames use materials such as titanium alloys and aluminum alloys to fabricate a supporting frame. Hydrophone elements are fixed to the frame by mechanical fixation or adhesive bonding and encapsulated in sound-permeable materials such as polyurethane, forming a shape conformal to the bow profile.

[0004] The drawback of the existing technology is that if a rigid frame based on traditional metal is used, the acoustic impedance of the material (such as aluminum alloy 17 MRayl) is severely mismatched with the water body (1.5 MRayl), which will inevitably cause most of the sound wave energy to be reflected at the frame interface, resulting in a decrease in the overall sound transmission performance of the receiving array. The sound waves cannot be effectively transmitted to the array element hydrophone, causing a sharp drop in the low-frequency sensitivity that is crucial for long-distance detection.

[0005] Furthermore, in practical applications, long-term mechanical vibration and thermal cycling will inevitably lead to a decline in the adhesion between the potting compound and the smooth, chemically inert skeleton surface (especially carbon fiber or metal), and may even result in debonding. Debonding will directly cause interruption of the acoustic channel and failure of watertightness, ultimately threatening the long-term reliability of the entire receiver array module.

[0006] Because bow-mounted thrusters are located further away from the stern propellers of the platform and are placed within the bow guide structure during application, bow-mounted thrusters have advantages over side-mounted and stern-towed thrusters, such as being less affected by stern vibrations and not impacting platform maneuverability. However, bow-mounted thrusters face the following three core technical challenges: (1) The support frame needs to achieve high-precision and high-density placement of array elements in a complex curved space under the harsh load constraints of the underwater unmanned platform, and ensure sufficient structural strength and pressure resistance.

[0007] (2) If the acoustic characteristic impedance of the skeleton material is seriously mismatched with that of the water body, it will produce significant acoustic reflection and transmission loss, which will degrade the sound transmission performance of the receiving array, especially the low-frequency response.

[0008] (3) Under harsh working conditions of vibration, impact and long-term water pressure circulation, it is necessary to ensure the solid integration between the array elements, cables, potting compound and skeleton, prevent failures such as debonding and water seepage, and ensure the long-term stability of acoustic performance. Summary of the Invention

[0009] The technical problem to be solved by this invention is the prominent contradiction between the need to improve the detection capability of underwater unmanned platforms and the limited space and load of the platforms. Therefore, this invention provides a composite material skeleton for curved thin-shell receiving arrays, its manufacturing method, and its application.

[0010] The technical solution of this invention is as follows: A composite material frame for a curved thin-shell receiving array, the composite material frame including a support frame, the support frame having multiple array element mounting slots, array element wiring holes on the array element mounting slots, multiple rubber through holes evenly arranged on the support frame outside the array element mounting slots, several fixing bracket connection holes on the support frame, and multiple transition parts on the outside of the support frame, the transition parts having frame mounting holes, and connectors installed on the frame mounting holes.

[0011] Preferably, the support frame is made of carbon fiber material, the connector is an integrally formed titanium alloy connector, and the vibration damping rubber pad is a neoprene vibration damping rubber pad; one end of the titanium alloy connector is installed on the support frame by fasteners, and the other end is installed on the platform and / or other receiving array by fasteners and vibration damping rubber pads.

[0012] Preferably, a copper mesh shielding layer is provided in the layup within the support frame. The copper mesh shielding layer has multiple array element through holes and multiple rubber through holes. The copper mesh shielding layer matches the specifications and shape of the support frame. The copper mesh shielding layer is also connected to the ground wire of the array element hydrophone.

[0013] Preferably, multiple electromagnetic shielding grooves are arranged in an orderly manner on the inner surface of the support frame. The ends of the electromagnetic shielding grooves are connected to the wiring holes of the array elements. The wires of the hydrophones of each array element are led out from the wiring holes of the array elements and arranged in the electromagnetic shielding grooves. Several wiring lead-out points are set on the electromagnetic shielding grooves.

[0014] Preferably, the support frame is a curved thin-layer support frame, the array element mounting grooves are evenly opened on the front side of the support frame, the depth of the array element mounting grooves is 1 / 3 of the thickness of the support frame, and there are multiple rubber through holes evenly arranged in the low-stress area outside the array element mounting grooves.

[0015] The present invention also provides a method for fabricating a composite material skeleton for a curved thin-shell receiving array, comprising the following steps: S1. Fabrication of copper mesh shielding layer: The copper mesh shielding layer is integrally formed by mold. The copper mesh shielding layer is provided with multiple array element wire holes and multiple rubber through holes, and is matched with the specifications and shape of the support frame. S2. Fabrication of composite material skeleton: The composite material skeleton is integrally formed on the outside of the copper mesh shielding layer using a mold. The front of the composite material skeleton is provided with multiple array element mounting slots and multiple rubber through holes. Array element wiring holes are provided in the array element mounting slots. The composite material skeleton is also provided with several fixed bracket connection holes. The back of the composite material skeleton is provided with multiple electromagnetic shielding grooves that connect to the array element wiring holes. The electromagnetic shielding grooves are used to lead out the array element hydrophone wiring. Several skeleton mounting holes are provided on the outside of the composite material skeleton. S3. Manufacturing and installation accessories: The installation accessories include connectors, vibration damping rubber pads, and fixing brackets. The connectors are adapted to the frame mounting holes on the outside of the composite material frame. The connectors are integrally formed by molds and are provided with frame connection holes and / or platform connection holes. The fixing brackets are adapted to the fixing bracket connection holes on the composite material frame. The fixing brackets are integrally formed by molds. The vibration damping rubber pads have connection holes that mate with the connectors and are integrally formed by molds.

[0016] Preferably, in step S2, the composite material skeleton is made of carbon fiber; in step S3, the connector is made of titanium alloy and the vibration damping rubber pad is made of neoprene rubber.

[0017] The present invention also provides a method for fabricating a curved thin-shell receiving array using the above-mentioned composite material skeleton, comprising the following steps: S1. Install the hydrophone and arrange the wires: Place the array element hydrophone into the array element mounting slot of the composite material skeleton. The wires of the array element hydrophone are led out after passing through the array element wiring hole. Among them, the signal line and the power line are led out from the electromagnetic shielding groove on the back of the composite material skeleton. The ground wire of the power line is connected to the copper mesh shielding layer. S2. Potting and shaping: Through mold forming process, a certain thickness of adhesive is potted to seal the array element hydrophone and the composite material skeleton as a whole. S3. Assemble and install accessories: Install the appropriate connectors and vibration damping rubber pads onto the mounting holes of the frame to complete the fabrication of the curved thin-shell receiver array.

[0018] Preferably, in step S2, the potting adhesive layer is integrally connected on the front and back of the support frame through the rubber through hole, and a frame mounting hole for installing the connector is left after potting.

[0019] Preferably, in step S1, a PCB adapter module is installed using a fixed bracket and wired to the array element hydrophone; in step S2, the PCB adapter module and each wire are integrally encapsulated with the support frame on the back of the support frame using a mold forming process.

[0020] The advantages of this invention are: 1. Carbon fiber composite material is used as the supporting frame. Due to the advantages of high strength and lightweight, carbon fiber composite material reduces the weight of the underwater receiving array module while ensuring the structural strength of the frame. Since the acoustic impedance of carbon fiber is close to that of water, the sound transmission performance of the receiving array module is improved. In addition, array element positions are set on the frame, with the thickness of the array element position being 1 / 3 of the frame thickness, and a wiring hole is set in the center of the array element position to further improve the sound wave transmission capability.

[0021] 2. High-precision positioning of array elements is achieved by pre-setting array element positions on the frame. In addition, the array elements are partially recessed into their positions, reducing the overall thickness of the receiving array.

[0022] 3. By adopting an equal-angle array design along the latitude and longitude, the array elements of the receiving array are evenly and densely distributed, increasing the sensing area of ​​the receiving array and improving its sensing performance.

[0023] 4. By setting multiple rubber through holes in areas of low structural stress on the carbon fiber skeleton, the bonding force between the adhesive layer and the skeleton is transformed from a fragile interfacial adhesive force to a strong macroscopic mechanical anchoring force. The effect is that it greatly improves the anti-debonding ability and sealing reliability of the receiving array module under long-term underwater pressure cycling, temperature changes and mechanical vibration environment. It realizes the connection between the front and back of the rubber after the receiving array is filled, forming a mechanical interlocking effect between the sealant and the skeleton, effectively solving the reliability problem of the potting adhesive layer easily peeling off from the smooth skeleton surface, and improving the reliability of the receiving array.

[0024] 5. The through-holes, as an acoustic channel network, further enhance sound wave transmission, reduce the perturbation of the sound field by the frame, and extend the operating frequency band. The multifunctional frame structure design achieves a coupling between structural manufacturing and functional adaptation. Furthermore, the through-holes on the frame are specifically designed.

[0025] 6. During assembly, neoprene damping rubber is installed at the joint between the titanium alloy connector and the frame. The damping effect of the rubber is used to isolate and attenuate the broadband mechanical vibration from the platform, preventing it from being transmitted to the receiving array and improving the vibration resistance of the curved thin shell receiving array.

[0026] 7. The overall design is reasonable, lightweight, high-strength, easy to install and use, has good sound transmission performance, high positioning accuracy, dense array element distribution, good vibration resistance, and is safe and reliable. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the front structure of the composite material skeleton of the present invention; Figure 2 This is a schematic diagram of the back side of the composite material skeleton of the present invention; Figure 3 This is a schematic diagram of the copper mesh shielding layer in this invention; Figure 4 This is a schematic diagram of the structure of the titanium alloy connector in this invention; Figure 5 This is a schematic diagram of the structure of the composite material skeleton with the array element hydrophone mounted on the front. Figure 6 This is a schematic diagram of the structure of mounting the PCB adapter module on the back of the composite material skeleton of the present invention; Figure 7a A comparison of acoustic transmission loss (reflection coefficient) for four materials (carbon fiber, aluminum alloy, titanium alloy, and stainless steel) at a thickness of 6 mm. Figure 7b A comparison of acoustic transmission loss (transmission coefficient) for four materials (carbon fiber, aluminum alloy, titanium alloy, and stainless steel) at a thickness of 6 mm. In the diagram: 1-Support frame, 2-Element mounting slot, 3-Element wiring hole, 4-Rubber through hole, 5-Frame mounting hole, 6-Titanium alloy connector, 7-Electromagnetic shielding groove, 8-Copper mesh shielding layer, 9-Element hydrophone, 10-Fixed bracket, 11-PCB adapter module. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments and accompanying drawings: The disadvantages of the existing curved receiving array skeleton are: (1) the traditional high-strength metal structure design seriously encroaches on the limited load of the underwater unmanned platform and makes it difficult to achieve high sound wave transmission; (2) it is difficult to achieve dense arraying and precise positioning of curved thin shell receiving array elements in the limited space of the platform; (3) due to the complexity and severity of underwater application scenarios, the receiving array with embedded support skeleton 1 has the potential for debonding between different material layers after long-term use, which seriously affects the service life of the receiving array.

[0029] This invention provides a design scheme for the support frame 1 of the conformal receiving array at the bow of an underwater unmanned platform, the overall concept of which is as follows: 1. By rigidly integrating the array into the bow of the underwater unmanned platform, the negative impact of towed arrays on the platform's maneuverability and stealth is fundamentally avoided. At the same time, the impact of platform stern vibration noise on the receiving array is greatly reduced, providing an underwater unmanned platform with a high-performance sonar solution that does not affect its platform characteristics.

[0030] 2. The supporting frame 1 is designed with carbon fiber material, the core of which is to improve structural stability while reducing the impact of the "acoustic mismatch" of the metal frame. The frame design proposed in this invention needs to combine the dimensional stability of a rigid structure with the excellent sound transmission of the composite material (acoustic impedance close to water).

[0031] 3. A multifunctional porous array topology carbon fiber support skeleton 1 is proposed. Through its inherent high stiffness and high strength, it provides a permanent and accurate three-dimensional spatial coordinate reference for the array elements, thereby eliminating the uncertainty of the array element position.

[0032] 4. By utilizing the acoustic impedance of the carbon fiber material to be close to that of water, and designing it as a perforated array topology structure, the acoustic wave transmission area is maximized, thereby constructing a propagation path with high acoustic transparency, which significantly improves the sensitivity of the receiving array, especially the low-frequency response.

[0033] 5. A specific rubber through-hole 4 is proposed to be designed on the frame. From the perspective of the engineering implementation of the receiving array, this will create a mechanical interlocking effect, eliminate the risk of debonding, and ensure the functional integrity of the receiving array throughout its entire life cycle. In addition, the through-hole constitutes an acoustic channel network, realizing acoustic continuity before and after the frame.

[0034] Example 1: Embodiment 1 of the present invention provides a composite material frame for a curved thin-shell receiving array. The composite material frame includes a support frame 1, which is provided with multiple array element mounting slots 2. The array element mounting slots 2 are provided with array element wiring holes 3. Multiple rubber through holes 4 are evenly arranged on the support frame 1 outside the array element mounting slots 2. Fixed bracket 10 connection holes are provided on both sides of the bottom of the support frame 1. The support frame 1 also has multiple transition parts on the outside. The transition parts are provided with frame mounting holes 5. Connectors are installed on the frame mounting holes 5. The connectors are used to fix the support frame 1 to the platform and / or other receiving arrays.

[0035] In this embodiment, the composite material skeleton is a support skeleton 1 made of carbon fiber material, the connector is an integrally formed titanium alloy connector 6, and the vibration damping rubber pad is a 2mm thick neoprene vibration damping rubber pad. The titanium alloy connector 6 has skeleton connection holes and platform connection holes. One end of the titanium alloy connector 6 is mounted on the support skeleton 1 by fasteners installed on the skeleton connection holes, and the other end is mounted on the platform and / or other receiving arrays by fasteners installed on the platform connection holes and the vibration damping rubber pad.

[0036] In this embodiment, a copper mesh shielding layer 8 is provided in the layup within the support frame 1. The copper mesh shielding layer 8 has multiple array element through holes and multiple rubber through holes 4. The copper mesh shielding layer 8 matches the specifications and shape of the support frame 1. The copper mesh shielding layer 8 is also connected to the ground wire of the array element hydrophone 9, forming a large-area, low-impedance power distribution network and grounding plane, thereby improving the electromagnetic interference resistance of the curved thin-shell receiving array.

[0037] In this embodiment, multiple electromagnetic shielding grooves 7 are arranged in an orderly manner on the inner surface of the support frame 1. The ends of the electromagnetic shielding grooves 7 are connected to the array element wiring holes 3. The wires of each array element hydrophone 9 are led out from the array element wiring holes 3 and arranged in the electromagnetic shielding grooves 7. Several wiring lead-out points are set on the electromagnetic shielding grooves 7. By setting electromagnetic shielding grooves 7 that cooperate with the array element wiring holes 3 on the support frame 1, the electromagnetic shielding grooves 7 and the array element wiring holes 3 on the support frame 1 can achieve the path standardization of the high-density wire bundle inside the curved receiving array, effectively reduce the complexity of wiring, and improve the anti-electromagnetic interference performance between the array element hydrophones 9.

[0038] In this embodiment, the support frame 1 is a curved thin-layer support frame 1 with an outer radius of 210mm. The number of array elements placed on the support frame 1 is 14. The array element mounting grooves 2 are evenly opened on the front side of the support frame 1. The array element mounting grooves 2 are arranged at equal angles in latitude and longitude. The depth of the array element mounting grooves 2 is 1 / 3 of the thickness of the support frame 1. There are multiple rubber through holes 4, which are evenly arranged in the low-stress area outside the array element mounting grooves 2. The rubber through holes 4 achieve an integral connection of the potting adhesive layer on the front and back sides of the support frame 1 by injecting adhesive.

[0039] In this embodiment, the array element mounting slot 2 is used to further install the array element hydrophone 9. The signal line and power line of the array element hydrophone 9 are led out after passing through the array element wiring hole 3, and then the array element hydrophone 9 is fixed on the support frame 1 by the potting adhesive layer.

[0040] Furthermore, in conjunction with the appendix Figure 1 To be continued Figure 7a , 7b The specific explanation is as follows: The composite material skeleton provided in Embodiment 1 of the present invention mainly consists of a carbon fiber skeleton and titanium alloy connectors 6. The structure of the carbon fiber skeleton is as follows: Figure 1 , Figure 2 As shown, a copper mesh shielding layer 8 is set inside the composite material skeleton. Figure 3 As shown, the structure of the titanium alloy connector 6 is as follows: Figure 4 As shown, the applied curved thin-shell type receiver array is as follows: Figure 5 , Figure 6As shown. The carbon fiber skeleton adopts a hole array topology design, which includes positioning holes, wiring holes, rubber through holes, mounting holes, etc.

[0041] This invention is based on a carbon fiber skeleton with an outer radius of 210 mm for array design. Based on the surface area of ​​the curved surface and the effective array area of ​​the array elements, and combined with multi-objective optimization design considering performance, cost, and engineering implementation, the optimal balance between acoustic performance and structural space utilization is achieved when 14 array elements are placed on the support skeleton 1.

[0042] The positioning holes are one-third the thickness of the frame, and their positions are designed according to a uniform, close-packed arrangement at equal angles. On one hand, the depth is sufficient to ensure precise positioning of the array elements, resist misalignment forces during the manufacturing process, and guarantee array accuracy. Furthermore, the design of the positioning holes provides a physical reference for the phase center array; on the other hand, the element positions retain a certain thickness of carbon fiber, sufficient to maintain the overall structural strength of the frame and ensure the reliability of the receiving array.

[0043] To enhance the bonding reliability between the skeleton and the waterproof adhesive layer, rubber through-holes are incorporated into the skeleton to allow the potting polyurethane adhesive to flow continuously, creating a strong mechanical interlocking effect. Based on finite element analysis, the rubber through-holes 4 are preferentially located in areas of lower stress within the skeleton structure and evenly distributed in the blank areas between the positioning holes. This layout aims to ensure that the polyurethane adhesive forms a continuous, interconnected three-dimensional network, maximizing the contact area between the adhesive and the skeleton, thereby most effectively eliminating the risk of debonding while avoiding weakening the main load-bearing structure of the skeleton.

[0044] To prevent water seepage from the carbon fiber material after prolonged immersion in water, titanium alloy, which has low density, high strength, and corrosion resistance, is preferred as the material for the connectors. The structure is as follows: Figure 4 As shown.

[0045] After connecting the titanium alloy connector 6 to the frame with bolts, considering the vibration impact of the platform in actual application scenarios, a 2mm thick neoprene vibration-damping rubber pad is applied between the titanium alloy connector 6 and the frame. The function of the rubber pad is to isolate and attenuate broadband mechanical vibrations from the platform, preventing them from being transmitted to the receiving array, thereby ensuring that the receiving array operates in a quiet environment. At the same time, connection holes for connecting to the platform are provided on the titanium alloy connector 6. The connection holes can be used to connect to the platform on the one hand, and to connect the receiving array modules on the other hand.

[0046] like Figure 7a , Figure 7b As shown, compared with traditional metal materials such as aluminum alloys, titanium alloys and stainless steel, the carbon fiber material used in the embodiments of the present invention can significantly reduce sound propagation loss in terms of reflection coefficient and transmission coefficient, and the material performance is superior.

[0047] Example 2: Embodiment 2 of the present invention provides a method for fabricating a composite material skeleton for a curved thin-shell receiving array, used to fabricate the composite material skeleton of Embodiment 1, comprising the following steps:

[0048] S1. Fabricating copper mesh shielding layer 8: The copper mesh shielding layer 8 is integrally formed by a mold. The copper mesh shielding layer 8 is provided with multiple array element wire holes and multiple rubber through holes 4, and is matched with the specifications and shape of the support frame 1. S2. Fabrication of composite material skeleton: A composite material skeleton is integrally formed on the outside of the copper mesh shielding layer 8 using a mold. The front of the composite material skeleton is provided with multiple array element mounting grooves 2 and multiple rubber through holes 4. Array element wiring holes 3 are provided in the array element mounting grooves 2. Several fixing bracket 10 connection holes are also provided on the composite material skeleton. Multiple electromagnetic shielding grooves 7 connected to the array element wiring holes 3 are provided on the back of the composite material skeleton. The electromagnetic shielding grooves 7 are used to lead out the wiring of the array element hydrophone 9. Several skeleton mounting holes 5 are provided on the outside of the composite material skeleton. S3. Manufacturing and installation accessories: The installation accessories include connectors, vibration damping rubber pads, and fixing brackets 10. The connectors are adapted to the frame mounting holes 5 on the outside of the composite material frame. The connectors are integrally formed by molds. The connectors are provided with frame connection holes and / or platform connection holes. The fixing brackets 10 are adapted to the fixing bracket 10 connection holes on the composite material frame. The fixing brackets 10 are integrally formed by molds. The vibration damping rubber pads have connection holes that mate with the connectors. The vibration damping rubber pads are integrally formed by molds.

[0049] In this embodiment, in step S2, the composite material skeleton is made of carbon fiber; in step S3, the connector is made of titanium alloy and the vibration damping rubber pad is made of neoprene rubber.

[0050] Example 3: Embodiment 3 of the present invention provides a method for fabricating a curved thin-shell receiving array using the composite material skeleton of Embodiment 1, comprising the following steps: S1. Install the hydrophone and arrange the wires: Place the array element hydrophone 9 into the array element mounting slot 2 of the support frame 1. Each wire of the array element hydrophone 9 is led out after passing through the array element wiring hole 3. The wires include positive signal line and negative signal line, i.e. signal line. The wires also include positive pole line, negative pole line and ground line, i.e. power line. The signal line and power line are led out from the electromagnetic shielding groove 7 on the back of the composite material frame. The ground line is also connected to the copper mesh shielding layer 8. S2. Filling and shaping: Through mold forming process, fill a certain thickness of adhesive to seal the array element hydrophone 9 and the support frame 1 as a whole. S3. Assemble and install accessories: Install the appropriate connectors and vibration damping rubber pads onto the frame mounting holes 5 to complete the fabrication of the curved thin-shell receiver array.

[0051] In this embodiment, in step S2, the potting adhesive layer is integrally connected on the front and back sides of the support frame 1 through the rubber through hole 4, and after potting, a frame mounting hole 5 for installing the connector is left.

[0052] In this embodiment, in step S1, the PCB adapter module 11 is also installed via the fixing bracket 10 and connected to the signal line and power line of the array element hydrophone 9. In step S2, the PCB adapter module 11 and its wiring are integrally encapsulated on the back of the support frame 1 with the support frame 1 using a mold forming process. After encapsulation, the cable connector of the PCB adapter module 11 is located outside the encapsulation layer.

[0053] This invention has the following characteristics: 1. The curved thin-shell receiver array support frame 1 is made of carbon fiber. Utilizing the characteristics of carbon fiber—low density, high strength, and characteristic impedance close to that of water—the acoustic transmission performance of the underwater receiver array module is improved while ensuring the structural strength of the receiver array. Furthermore, carbon fiber is easy to process and shape, allowing for array arrangements with different curved surfaces based on the bow space characteristics of different platforms.

[0054] 2. A thin carbon fiber skeleton is selected, and a depth of 1 / 3 of the skeleton thickness is carved out at the center point of each array element mounting slot on the skeleton. The bottom of the positioning hole is flat, and the array element hydrophone 9 is partially sunk into the skeleton. On the one hand, this realizes the limiting design of the array element hydrophone 9 and prevents the risk of array element misalignment during the development of the receiving array; on the other hand, it reduces the overall thickness of the curved receiving array, improves sound wave transmission, and realizes the lightweight design of the receiving array.

[0055] 3. The carbon fiber skeleton adopts a hole array topology design, with corresponding holes set in the array element mounting slots to further enhance the transmission capability of sound waves.

[0056] 4. The array elements are evenly and densely distributed by adopting an equal-angle array design in latitude and longitude, which increases the sensing area of ​​the receiving array and improves the detection performance of the receiving array.

[0057] 5. Through simulation analysis, multiple rubber through holes are set in the low stress area of ​​the skeleton structure. The purpose is to make the potting compound form a three-dimensional continuous mechanical interlocking structure. The rubber through holes 4 on the skeleton enable the rubber to be connected front and back after potting, reducing the risk of the rubber debonding from the skeleton after long-term use and improving the reliability of the receiving array module.

[0058] 6. Based on the platform characteristics of skeleton application, this invention designs through holes of different densities and sizes in different regions, and combines them with the control of the potting compound after arraying to realize the active control of the local impedance of different regions of the shell, reserving expansion space for the later realization of acoustic metasurface function.

[0059] 7. The rubber through holes are not only mechanical anchor points, but also key nodes that form an acoustic channel network, achieving acoustic continuity between the front and rear sides, avoiding high-frequency sound wave reflection and internal resonance caused by impedance fluctuations in the support frame 1, thereby widening the effective working frequency band.

[0060] 8. Due to the material properties of carbon fiber, it is impossible to set threaded holes inside the carbon fiber, and the skeleton is relatively thin, making it difficult to embed threaded structures. Therefore, titanium alloy connectors 6 are used to connect the carbon fiber skeleton to the platform, improving the adaptability and reliability of the receiving array.

[0061] 9. By setting a 2mm neoprene vibration damping rubber pad at the connection of the titanium alloy connector 6, the broadband mechanical noise of the platform is isolated, which helps to improve the vibration resistance of the receiving array module.

[0062] It should be noted that the above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Equivalent modifications made based on the above embodiments are all within the scope of protection of the present invention.

Claims

1. A composite framework for a curved thin shell type receiving array, characterized by, The composite material skeleton includes a support skeleton, which is provided with multiple array element mounting slots. The array element mounting slots are provided with array element wiring holes. Multiple rubber through holes are evenly arranged on the support skeleton outside the array element mounting slots. Several fixed bracket connection holes are provided on the support skeleton. The support skeleton also has multiple transition parts on its outer side. The transition parts are provided with skeleton mounting holes, and connectors are installed on the skeleton mounting holes.

2. A composite framework for a curved thin shell type receiving array according to claim 1, wherein: The support frame is made of carbon fiber material, the connector is an integrally formed titanium alloy connector, and the vibration damping rubber pad is a neoprene vibration damping rubber pad; one end of the titanium alloy connector is installed on the support frame by fasteners, and the other end is installed on the platform and / or other receiving array by fasteners and vibration damping rubber pads.

3. A composite framework for a curved thin shell type receiving array according to claim 1, wherein: A copper mesh shielding layer is set in the layup within the support frame. The copper mesh shielding layer has multiple array element through holes and multiple rubber through holes. The copper mesh shielding layer matches the specifications and shape of the support frame. The copper mesh shielding layer is also connected to the ground wire of the array element hydrophone.

4. A composite framework for a curved thin shell type receiving array according to claim 1, wherein: Multiple electromagnetic shielding grooves are arranged in an orderly manner on the inner surface of the support frame. The ends of the electromagnetic shielding grooves are connected to the wiring holes of the array elements. The wires of the hydrophones of each array element are led out from the wiring holes of the array elements and arranged in the electromagnetic shielding grooves. Several wiring lead-out points are set on the electromagnetic shielding grooves.

5. A composite material frame for a curved thin-shell receiving array according to claim 1, characterized in that: The support frame is a curved thin-layer support frame. The array element mounting grooves are evenly opened on the front side of the support frame. The depth of the array element mounting grooves is 1 / 3 of the thickness of the support frame. There are multiple rubber through holes, which are evenly arranged in the low-stress area outside the array element mounting grooves.

6. A method for fabricating a composite material skeleton for a curved thin-shell receiving array, characterized in that, Includes the following steps: S1. Fabrication of copper mesh shielding layer: The copper mesh shielding layer is integrally formed by mold. The copper mesh shielding layer is provided with multiple array element wire holes and multiple rubber through holes, and is matched with the specifications and shape of the support frame. S2. Fabrication of composite material skeleton: The composite material skeleton is integrally formed on the outside of the copper mesh shielding layer using a mold. The front of the composite material skeleton is provided with multiple array element mounting slots and multiple rubber through holes. Array element wiring holes are provided in the array element mounting slots. The composite material skeleton is also provided with several fixed bracket connection holes. The back of the composite material skeleton is provided with multiple electromagnetic shielding grooves that connect to the array element wiring holes. The electromagnetic shielding grooves are used to lead out the array element hydrophone wiring. Several skeleton mounting holes are provided on the outside of the composite material skeleton. S3. Manufacturing and installation accessories: The installation accessories include connectors, vibration damping rubber pads, and fixing brackets. The connectors are adapted to the frame mounting holes on the outside of the composite material frame. The connectors are integrally formed by molds and are provided with frame connection holes and / or platform connection holes. The fixing brackets are adapted to the fixing bracket connection holes on the composite material frame. The fixing brackets are integrally formed by molds. The vibration damping rubber pads have connection holes that mate with the connectors and are integrally formed by molds.

7. A method for fabricating a composite material skeleton for a curved thin-shell receiving array according to claim 6, characterized in that: In step S2, the composite material skeleton is made of carbon fiber; in step S3, the connector is made of titanium alloy and the vibration damping rubber pad is made of neoprene rubber.

8. A method for fabricating a curved thin-shell receiving array using the composite material skeleton as described in claim 1, characterized in that, Includes the following steps: S1. Install the hydrophone and arrange the wires: Place the array element hydrophone into the array element mounting slot of the composite material skeleton. The wires of the array element hydrophone are led out after passing through the array element wiring hole. Among them, the signal line and the power line are led out from the electromagnetic shielding groove on the back of the composite material skeleton. The ground wire of the power line is connected to the copper mesh shielding layer. S2. Potting and shaping: Through mold forming process, a certain thickness of adhesive is potted to seal the array element hydrophone and the composite material skeleton as a whole. S3. Assemble and install accessories: Install the appropriate connectors and vibration damping rubber pads onto the mounting holes of the frame to complete the fabrication of the curved thin-shell receiver array.

9. The method for fabricating a curved thin-shell receiving array using the composite material skeleton as described in claim 1, as described in claim 8, is characterized in that: In step S2, the potting adhesive layer is integrally connected on the front and back of the support frame through the rubber through hole, and a frame mounting hole for installing the connector is left after potting.

10. The method for fabricating a curved thin-shell receiving array using the composite material skeleton as described in claim 1, as described in claim 8, is characterized in that: In step S1, the PCB adapter module is installed by a fixed bracket and wired to the array element hydrophone; in step S2, the PCB adapter module and each wire are integrally encapsulated with the support frame on the back of the support frame by a mold forming process.

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