Multistage hole-ladder grid sandwich plate sound absorption load integrated structure and manufacturing method

Abstract

This invention discloses a multi-level perforated trapezoidal grid sandwich panel with integrated sound absorption and load-bearing structure and manufacturing method. The panel assembly consists of an upper panel and a lower panel arranged in parallel intervals. A mechanical reinforcement layer divides the area between the upper and lower panels into multiple independent filling spaces. An acoustic functional layer is disposed within the filling spaces, comprising a perforated trapezoidal core material layer and a micro-perforated thin plate, which are alternately layered and bonded together. The perforated trapezoidal core material layer has millimeter-level first perforations, and the micro-perforated thin plate has sub-millimeter-level second perforations. The first perforations and multiple second perforations are aligned at the bonding point between the perforated trapezoidal core material layer and the micro-perforated thin plate, forming a multi-level perforated channel with a stepped aperture. Through structural innovation, the synergistic coupling of sound absorption and load-bearing functions is achieved. The application of composite materials gives the structure the characteristics of being lightweight and high-strength, meeting the dual requirements of weight reduction and strength for ships. At the same time, the simplified structural hierarchy helps to reduce manufacturing and maintenance difficulties.

Description

Technical Field

[0001] This invention relates to the field of ship noise control and structural strength technology, specifically to a multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure and manufacturing method. Background Technology

[0002] Broadband noise generated by ships during navigation severely restricts cabin comfort. Traditional separate structural and sound-absorbing designs are no longer sufficient to meet the needs of advanced ships due to their large weight, low space utilization, and poor environmental durability of the sound-absorbing layer. Developing an integrated structure that combines high load-bearing capacity with efficient broadband sound absorption has become a technological trend.

[0003] Currently, relevant research mainly includes types such as corrugated metal / honeycomb sandwich panels, sandwich panels with built-in complex acoustic superstructures, and simple composite sound-absorbing sandwich panels. Among them, corrugated metal / honeycomb sandwich panel structures utilize their own geometry to provide superior specific strength and specific stiffness, making them relatively mature load-bearing structures. However, their internal structure consists of interconnected regular cavities, resulting in a relatively simple sound wave dissipation mechanism and limited sound absorption. Furthermore, the metal materials are prone to corrosion in marine environments, making it difficult to modify them into high-efficiency acoustic resonant units while ensuring mechanical performance. Sandwich panels with built-in complex acoustic superstructures enhance sound absorption by introducing acoustic superstructures such as Helmholtz resonators, perforated plate arrays, or local resonant units. However, they generally suffer from complex structures and high manufacturing difficulty, making it difficult to achieve large-scale, low-cost manufacturing of large marine components. Simple composite sound-absorbing sandwich panels, such as those made by mechanically perforating the face or core of a composite sandwich panel or simply adding porous materials between layers, have conflicting load-bearing and acoustic functions. The perforations directly reduce the load-bearing area, resulting in a loss of stiffness and strength. At the same time, the sound-absorbing layer is only connected to the main load-bearing structure through an adhesive layer, forming a weak mechanical interface. Under complex alternating loads, it is prone to debonding failure, threatening structural safety and the durability of acoustic performance.

[0004] Existing solutions suffer from core problems such as complex manufacturing, high cost, mechanical weakness due to the introduction of functions, weak interfaces, and poor reliability. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, a multi-level perforated trapezoidal grid sandwich panel with integrated sound absorption and load-bearing structure and manufacturing method is provided, achieving a synergistic improvement in sound absorption and load-bearing performance while also considering lightweight and ease of assembly.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: Firstly, the multi-level perforated trapezoidal grid sandwich panel has an integrated sound absorption and load-bearing structure, including a panel assembly, a mechanical reinforcement layer, and an acoustic functional layer. The panel assembly consists of a top panel and a bottom panel arranged in parallel intervals; a mechanical reinforcement layer is fixedly connected between the top panel and the bottom panel, dividing the area between the top and bottom panels into multiple independent filling spaces. The acoustic functional layer is set within the filling space. The acoustic functional layer includes a perforated trapezoidal core material layer and a micro-perforated thin plate, which are stacked and bonded together in an alternating manner. The perforated trapezoidal core material layer is fixed to both sides of the micro-perforated thin plate. A first perforation of millimeters through the thickness direction is provided on the perforated trapezoidal core material layer, and a second perforation of sub-millimeter size is provided on the micro-perforated thin plate. The diameter of the first perforation is larger than that of the second perforation. The first perforation and multiple second perforations are aligned at the bonding point of the perforated trapezoidal core material layer and the micro-perforated thin plate, forming a multi-level pore channel with a step change in pore size.

[0007] According to the above technical solution, the mechanical reinforcement layer is an independent trapezoidal grid, which is embedded between the panel assembly, dividing the area between the upper and lower panels into multiple independent cavities with trapezoidal cross-sections, and the cavities serve as filling spaces.

[0008] According to the above technical solution, the trapezoidal grid is a trapezoidal grid structure arranged periodically and centrally symmetrically; it includes a bottom plate that is attached to the lower panel, a top plate that is attached to the upper panel, and a first inclined side plate and a second inclined side plate connected between the top plate and the bottom plate.

[0009] According to the above technical solution, at least one micro-perforated thin plate is provided in the filling space. According to the above technical solution, a micro-perforated thin plate is set in the filling space, and the micro-perforated thin plate divides the filling space into upper and lower layers. The perforated trapezoidal core material layer is placed in the upper and lower layers of the filling space.

[0010] According to the above technical solution, the material used for the perforated trapezoidal core layer is PVC foam or PU foam, and the first perforation at the millimeter level is processed by a mold in a periodic arrangement.

[0011] According to the above technical solution, the micro-perforated thin plate is a dense composite material plate, and the sub-millimeter level second perforations are uniformly distributed by laser drilling and other methods.

[0012] According to the above technical solution, the upper panel, trapezoidal grid, and lower panel are fiber-reinforced composite material laminates, and the fiber-reinforced composite material is glass fiber, aramid fiber, or carbon fiber.

[0013] According to the above technical solution, both the upper panel and the lower panel are pre-impregnated with epoxy resin-based carbon fiber, and the carbon fiber layup sequence is [0 / 90 / ±45]s, which is cured by hot pressing.

[0014] Secondly, a method for manufacturing an integrated sound-absorbing and load-bearing structure of a multi-level perforated trapezoidal grid sandwich panel, the method comprising: Lay the bottom panel inside the mold; The acoustic functional layer and the mechanical reinforcement layer located below the mechanical reinforcement layer are placed sequentially on the bottom plate, and the mechanical reinforcement layer is fixed on the bottom plate. An acoustic functional layer is placed on top of the mechanical reinforcement layer; Lay out the top panel; The mold is closed, a vacuum is drawn, and epoxy resin structural adhesive is injected to allow the structural adhesive to wet the interfaces of each component and cure, ultimately forming a complete multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure as described above.

[0015] According to the above technical solution, the acoustic functional layer located above or below the mechanical reinforcement layer is pre-cured and connected to the perforated trapezoidal core material and the micro-perforated thin plate by epoxy adhesive. After the two are bonded together, the first perforation and the second perforation are aligned at the interface to form a multi-level pore structure with stepped pore size.

[0016] The present invention has the following beneficial effects: 1. A mechanical reinforcement layer is installed between the top and bottom panels to connect them into a whole, improving the structure's load-bearing capacity. The mechanical reinforcement layer divides the area between the top and bottom panels into multiple independent filling spaces, and the acoustic functional layer is placed in an independent filling space to play a sound-absorbing role.

[0017] In addition, the acoustic functional layer is composed of a perforated trapezoidal core material layer and a micro-perforated thin plate. The multi-level pore structure formed by the millimeter-level first perforation in the perforated trapezoidal core material and the sub-millimeter-level second perforation in the micro-perforated thin plate, together with the mechanical reinforcement layer that serves as the acoustic rigid wall, forms an independent closed resonant cavity and works in conjunction with it to achieve the synergistic effect of Helmholtz resonance and micropore viscous dissipation, thus broadening the sound absorption frequency band and improving the problem of poor low-frequency sound absorption in traditional connected cavity sandwich panels.

[0018] 2. The independent trapezoidal grid serves as a mechanical reinforcement skeleton, and the design of the first and second inclined side plates as webs provides excellent bending and shear resistance. The trapezoidal grid and the upper and lower panels form multiple independent trapezoidal filling spaces. The trapezoidal filling spaces provide one-to-one support for multiple independent acoustic functional layers. A local reinforcement frame is formed in the core material opening area of ​​the acoustic functional layer, which effectively compensates for the stiffness reduction caused by the opening and avoids stress concentration.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0021] Fig. 1 This is a schematic diagram of the structure of an embodiment provided by the present invention; Fig. 2 This is a schematic diagram of the acoustic functional layer provided in an embodiment of the present invention; Fig. 3 This is a schematic diagram of the mechanical reinforcement layer provided in an embodiment of the present invention; Fig. 4 This is a schematic diagram of the structure of the micro-perforated thin plate provided in an embodiment of the present invention; In the diagram, 1. Panel assembly; 1-1. Top panel; 1-2. Bottom panel; 2. Mechanical reinforcement layer; 2-1. Bottom plate; 2-2. Top plate; 2-3. First inclined side plate; 2-4. Second inclined side plate; 3. Acoustic functional layer; 3-1. Perforated trapezoidal core material layer; 3-2. Micro-perforated thin plate; 4. First perforation; 5. Second perforation. Detailed Implementation

[0022] The following is in conjunction with the appendix Figs. 1-4 The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0023] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] Reference Figs. 1-4 As shown, the present invention provides an integrated sound-absorbing and load-bearing structure for a multi-level perforated trapezoidal grid sandwich panel.

[0026] Example 1 It includes panel assembly 1, mechanical reinforcement layer 2, and acoustic functional layer 3; The panel assembly consists of an upper panel 1-1 and a lower panel 1-2 arranged in parallel intervals; a mechanical reinforcement layer is fixedly connected between the upper panel and the lower panel, dividing the area between the upper and lower panels into multiple independent filling spaces. The acoustic functional layer is set within the filling space. The acoustic functional layer includes an open-pore trapezoidal core material layer 3-1 and a micro-perforated thin plate 3-2, which are stacked and bonded together in an alternating manner. The open-pore trapezoidal core material layer is fixed to both sides of the micro-perforated thin plate. A first perforation 4 with a millimeter-level diameter is provided on the open-pore trapezoidal core material layer along the thickness direction, and a second perforation 5 with a sub-millimeter-level diameter is provided on the micro-perforated thin plate. The diameter of the first perforation is larger than that of the second perforation. The first perforation and multiple second perforations are aligned at the bonding point of the open-pore trapezoidal core material layer and the micro-perforated thin plate, forming a multi-level pore channel with a step change in pore size.

[0027] In the above structure, a mechanical reinforcement layer is placed between the top and bottom panels, connecting the top and bottom panels into a whole and improving the load-bearing capacity of the structure. The mechanical reinforcement layer divides the area between the top and bottom panels into multiple independent filling spaces, and the acoustic functional layer is placed in an independent filling space to play a sound absorption role.

[0028] In addition, the acoustic functional layer is composed of a perforated trapezoidal core material layer and a micro-perforated thin plate. The multi-level pore structure formed by the millimeter-level first perforation in the perforated trapezoidal core material and the sub-millimeter-level second perforation in the micro-perforated thin plate, together with the mechanical reinforcement layer that serves as the acoustic rigid wall, forms an independent closed resonant cavity and works in conjunction with it to achieve the synergistic effect of Helmholtz resonance and micropore viscous dissipation, thus broadening the sound absorption frequency band and improving the problem of poor low-frequency sound absorption in traditional connected cavity sandwich panels.

[0029] Example 2 Based on Embodiment 1, a preferred structure for the mechanical reinforcement layer is provided. The mechanical reinforcement layer is an independent trapezoidal grid embedded between the panel assemblies, dividing the area between the upper and lower panels into multiple independent cavities with trapezoidal cross-sections, which serve as filling spaces. The trapezoidal units of the trapezoidal grid correspond to and enclose the perforated trapezoidal core material in the planar projection.

[0030] Specifically, the trapezoidal grid is a trapezoidal grid structure arranged periodically and centrally symmetrically; it includes a bottom plate 2-1 attached to the lower panel, a top plate 2-2 attached to the upper panel, and a first inclined side plate 2-3 and a second inclined side plate 2-4 connecting the top plate and the bottom plate. Specifically, several bottom plates are spaced apart and attached to the upper surface of the bottom plate, and several top plates are attached to the lower surface of the upper plate; in a horizontal projection, the bottom and top plates are arranged alternately. The first and second inclined side plates are alternately connected between the bottom and top plates, and the top plate, first inclined side plate, bottom plate, and second inclined side plate are sequentially and periodically fixedly connected. The top plate, first inclined side plate, second inclined side plate, and the upper surface of the lower panel constitute the trapezoidal cavity (i.e., the filling space), and the bottom plate, first inclined side plate, second inclined side plate, and the lower surface of the upper panel constitute the trapezoidal cavity (i.e., the filling space).

[0031] In the above structure, the independent trapezoidal grid serves as a mechanically reinforcing skeleton, and the design of the first and second inclined side plates as webs provides excellent bending and shear resistance. The trapezoidal grid and the upper and lower panels form multiple independent trapezoidal filling spaces, which provide one-to-one support for multiple independent acoustic functional layers. A local reinforcing frame is formed in the core material opening area of ​​the acoustic functional layer, which effectively compensates for the stiffness reduction caused by the opening and avoids stress concentration.

[0032] Example 3 Based on Example 2, at least one micro-perforated thin plate is provided within the filling space. One horizontal micro-perforated thin plate can be provided to divide a single filling space into upper and lower cavities; alternatively, multiple horizontal micro-perforated thin plates can be provided, arranged vertically within the filling space to divide a single filling space into upper, middle, and lower cavities.

[0033] As shown in the figure, a micro-perforated thin plate is set in the filling space, which divides the filling space into upper and lower layers. The perforated trapezoidal core material layer is placed in the upper and lower layers of the filling space.

[0034] In embodiments 1-3 above, the material used for the perforated trapezoidal core layer is PVC foam or PU foam, and the first perforations, arranged periodically at the millimeter level, are processed by a mold. The shape of the perforated trapezoidal core layer matches the shape of the filling space. The micro-perforated sheet is a dense composite material sheet, and the second perforations, evenly distributed at the sub-millimeter level, are processed by laser drilling or other methods.

[0035] In the above embodiments 1-3, the upper panel, trapezoidal grid, and lower panel are fiber-reinforced composite laminates, and the fiber-reinforced composite material is glass fiber, aramid fiber, or carbon fiber.

[0036] Both the top and bottom panels are pre-impregnated with epoxy resin-based carbon fiber, with the carbon fiber layup sequence being [0 / 90 / ±45]s. They are formed by hot pressing and curing, providing the main stiffness and in-plane strength.

[0037] This invention also provides a method for manufacturing a multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure, employing a vacuum-assisted resin injection process; the method includes... S1: Lay the bottom panel inside the mold; S2: Place the acoustic functional layer below the mechanical reinforcement layer and the mechanical reinforcement layer in sequence on the bottom panel, and fix the mechanical reinforcement layer on the bottom panel; the fixation here only needs to ensure that the mechanical reinforcement layer and the top panel do not slide relative to each other.

[0038] S3: Place an acoustic functional layer on top of the mechanical reinforcement layer; S4: Lay out the top panel; S5: Close the mold, evacuate and inject epoxy resin structural adhesive, so that the structural adhesive wets the interfaces of each component and cures, finally forming a complete multi-level hole-trapezoidal grid sandwich panel sound absorption and load-bearing integrated structure as described above.

[0039] In steps S2 and S3, the acoustic functional layer located above or below the mechanical reinforcement layer is pre-cured and connected to the perforated trapezoidal core material and the micro-perforated thin plate by epoxy adhesive. After the two are bonded together, the first perforation and the second perforation are aligned at the interface to form a multi-level pore structure with stepped pore size.

[0040] This invention achieves synergistic coupling of sound absorption and load-bearing functions through structural innovation. The application of composite materials makes the structure lightweight and high-strength, which can meet the dual requirements of weight reduction and strength of ships. At the same time, the simplified structural layers help reduce the difficulty of manufacturing and maintenance.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure, characterized in that: It includes a panel assembly, a mechanical reinforcement layer, and an acoustic functional layer; The panel assembly consists of a top panel and a bottom panel arranged in parallel intervals; a mechanical reinforcement layer is fixedly connected between the top panel and the bottom panel, dividing the area between the top and bottom panels into multiple independent filling spaces. The acoustic functional layer is set within the filling space. The acoustic functional layer includes a perforated trapezoidal core material layer and a micro-perforated thin plate, which are stacked and bonded together in an alternating manner. The perforated trapezoidal core material layer is fixed to both sides of the micro-perforated thin plate. A first perforation of millimeters through the thickness direction is provided on the perforated trapezoidal core material layer, and a second perforation of sub-millimeter size is provided on the micro-perforated thin plate. The diameter of the first perforation is larger than that of the second perforation. The first perforation and multiple second perforations are aligned at the bonding point of the perforated trapezoidal core material layer and the micro-perforated thin plate, forming a multi-level pore channel with a step change in pore size.

2. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 1, characterized in that: The mechanical reinforcement layer is an independent trapezoidal grid, which is embedded between the panel assemblies, dividing the area between the upper and lower panels into multiple independent cavities with trapezoidal cross-sections, which serve as filling spaces.

3. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 1, characterized in that: The trapezoidal grid is a trapezoidal grid structure arranged periodically and centrally symmetrically; it includes a bottom plate that is attached to the lower panel, a top plate that is attached to the upper panel, and a first inclined side plate and a second inclined side plate connected between the top plate and the bottom plate.

4. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 1, characterized in that: At least one micro-perforated thin plate is provided within the filling space.

5. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 1, characterized in that: A micro-perforated thin plate is placed in the filling space, which divides the filling space into upper and lower layers. The perforated trapezoidal core material layer is placed in the upper and lower layers of the filling space.

6. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 1, characterized in that: The material used for the perforated trapezoidal core layer is PVC foam or PU foam, and the first perforation at the millimeter level is periodically arranged by a mold. The micro-perforated thin plate is a dense composite material plate, with uniformly distributed sub-millimeter-level second perforations processed by laser drilling.

7. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 2, characterized in that: The upper panel, trapezoidal grid, and lower panel are fiber-reinforced composite laminates, and the fiber-reinforced composite materials are glass fiber, aramid fiber, or carbon fiber.

8. The multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 7, characterized in that: Both the top and bottom panels are pre-impregnated with epoxy resin-based carbon fiber, with the carbon fiber layup sequence being [0 / 90 / ±45]s, and are formed by hot pressing.

9. A method for manufacturing a multi-level perforated trapezoidal grid sandwich panel integrated sound-absorbing and load-bearing structure, characterized in that: The method includes Lay the bottom panel inside the mold; The acoustic functional layer and the mechanical reinforcement layer located below the mechanical reinforcement layer are placed sequentially on the bottom plate, and the mechanical reinforcement layer is fixed on the bottom plate. An acoustic functional layer is placed on top of the mechanical reinforcement layer; Lay out the top panel; The mold is closed, a vacuum is drawn, and structural adhesive is injected to allow the adhesive to permeate the interfaces of each component and cure, ultimately forming a complete multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure as described in any one of claims 1-8.

10. The method for manufacturing the multi-level perforated trapezoidal grid sandwich panel sound-absorbing and load-bearing integrated structure according to claim 9, characterized in that: The acoustic functional layer located above or below the mechanical reinforcement layer is pre-cured and connected to the perforated trapezoidal core material and the micro-perforated thin plate using epoxy adhesive. After the two are bonded together, the first perforation and the second perforation are aligned at the interface, forming a multi-level pore structure with stepped pore size.

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