Design and manufacturing method of honeycomb sandwich perforated plate composite structure

Abstract

The invention discloses a design and manufacturing method of a honeycomb sandwich perforated plate composite structure, which comprises the following steps: (1) filling a honeycomb cavity with a light material such as a porous material or aerogel and the like, further penetrating into the honeycomb cavity by using a drill bit when a perforating process is carried out on a surface skin, and forming pore channels in the filled light material, the diameter of the hole channel is the same as the perforation diameter of the skin, and the depth of the hole channel can be accurately controlled through CNC and other processes. (2) the honeycomb cavity is filled with a pre-machined light material, the appearance of the pre-machined light material is a hexagonal prism, the height of the pre-machined light material is smaller than or equal to the depth of the honeycomb cavity, and the pre-machined light material is provided with cylindrical or square ducts vertically downwards along the center of the upper surface. The honeycomb is subjected to skin treatment after being filled with the preprocessed light materials, and the skin is subjected to a perforating process. The characteristics of light weight, high strength and the like of the honeycomb sandwich composite structure are ensured, and the sound absorption performance of the composite material is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of honeycomb sandwich composite materials for noise control, in particular to a design and manufacturing method of a honeycomb sandwich perforated plate composite structure. Background Art

[0002] Honeycomb sandwich structure is a special type of composite material with the best specific strength and specific stiffness, and is widely used in the aerospace field. During aircraft cruising and high-speed train driving, noise sources such as engine blades, turbulence, and track friction generate strong noise in the cabin, seriously affecting ride comfort. In order to reduce the external noise of aircraft engines, a honeycomb perforated plate structure with good sound absorption performance is usually used. Common honeycomb perforated plate structures can form multi-degree-of-freedom honeycomb sound linings by adding interlayer perforated plates or embedded acoustic films.

[0003] Patent document CN116384022A discloses a method for constructing a honeycomb sound liner based on embedded tubes and different cavity depth configurations. The invention considers multiple honeycomb cavities connected in parallel, and each cavity is provided with an embedded tube. The diameter and length of the embedded tube are optimized to achieve the optimal sound absorption coefficient within a specific frequency band. However, since the honeycomb sound liner includes an embedded tube structure, it will face problems such as difficult processing and easy detachment of the embedded tube structure in engineering applications, which limits the actual use effect of the structure. In the present invention, by adding a lightweight porous sound-absorbing material to the honeycomb perforated plate structure and introducing channels in the lightweight material when the skin is perforated, it has the following advantages: (1) The traditional honeycomb perforated plate structure process can be adopted, and only the step of adding porous lightweight materials is redundant, and the characteristics of lightweight structure and high strength are retained; (2) The porous material is combined with the resonant structure to further improve the sound absorption performance of the structure.

[0004] Patent document CN111696502A discloses a double-layer honeycomb perforated plate underwater sound-absorbing metamaterial structure with a damping lining. The content of the present invention is different from the above-mentioned document in the following ways: (1) The application scenarios are different. The patent document is mainly used for underwater sound absorption, while the content of the present invention is applied to air sound absorption. (2) The sound absorption working principle is different. In this document, a damping lining is added to the honeycomb cavity, which essentially utilizes the resonance characteristics of the honeycomb cavity; in the content of the present invention, porous sound-absorbing material is filled in the honeycomb cavity, and channels connected to the surface skin perforations are left in the filling material, so as to achieve the coupling of porous material sound absorption and structural resonance sound absorption, broaden the sound absorption band of the traditional honeycomb sandwich perforated plate structure and enhance the sound absorption coefficient (see Figure 3 ).

[0005] Patent document CN113362795A discloses a petal-shaped channel porous sound absorption structure, which arranges a number of petal-shaped microchannels in parallel at intervals in the porous material to enhance the low-frequency sound absorption performance of the porous material. However, the mechanical bearing capacity of the structure is poor. In the present invention, by adding lightweight materials to the honeycomb sandwich perforated plate structure, the characteristics of the honeycomb sandwich structure with high strength and strong mechanical bearing capacity are retained, and it is suitable for complex working conditions such as aircraft wall panels, nacelle sound linings, etc. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention proposes a design and manufacturing method for a honeycomb sandwich perforated plate composite structure, which can take into account the characteristics of the traditional honeycomb sound lining structure such as light weight and high strength while further improving the sound absorption performance of the structure.

[0007] The technical solution of the present invention is as follows: An embodiment of the present invention provides a design and manufacturing method for a honeycomb sandwich perforated plate composite structure, which is composed of a back plate, a honeycomb and a perforated surface skin. The honeycomb cavity is filled with porous materials or lightweight materials such as aerogels, and the filling material has channels vertically downward along the upper surface.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] Technical solution 1, the method comprises the following steps:

[0010] Step 1: Perform bonding and heat treatment on the empty honeycomb and the back plate to connect the two.

[0011] Step 2: Fill the honeycomb cavity with porous materials or lightweight materials such as aerogel.

[0012] Step 3: Surface skinning of the filled honeycomb structure.

[0013] Step 4: Perform a perforation process on the surface skin, and further use the drill bit to penetrate into the honeycomb cavity to form channels in the filled lightweight material.

[0014] Technical solution 2, the method comprises the following steps:

[0015] Step 1: Perform bonding and heat treatment on the empty honeycomb and the back plate to connect the two.

[0016] Step 2: Pre-process the porous material or lightweight material such as aerogel. The shape of the pre-processed lightweight material is a hexagonal prism. The height of the pre-processed lightweight material is less than or equal to the depth of the honeycomb cavity. The pre-processed lightweight material has cylindrical or square channels vertically downward from the center of the upper surface.

[0017] Step 3: Fill the pre-processed lightweight material into the honeycomb cavity.

[0018] Step 4: Skinning the filled honeycomb structure.

[0019] Step 5: Perform perforation process on the surface skin.

[0020] The beneficial effects of the present invention are as follows:

[0021] (1) The design and manufacturing method of the honeycomb sandwich perforated plate composite structure proposed in the present invention can adopt the traditional honeycomb perforated plate structure process, and only the step of adding porous lightweight materials is redundant, and the characteristics of lightweight structure and high strength are retained. (2) On the basis of filling the honeycomb cavity with lightweight materials, the present invention further forms channels inside the lightweight materials, combines porous sound absorption with resonant structure sound absorption, and improves the overall sound absorption performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the honeycomb sandwich perforated plate composite structure in an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of a single honeycomb structure in an embodiment of the present invention;

[0024] In the figure, 1-perforation of the surface skin, 2-lightweight material filled in the honeycomb cavity, 3-vertical channel along the upper surface of the lightweight material, L-side length of the honeycomb, H-depth of the honeycomb cavity, t-thickness of the surface skin, d-diameter of the perforation of the surface skin, h-depth of the channel in the filling material.

[0025] Figure 3 It is a comparison of the sound absorption coefficients of the honeycomb sandwich perforated plate composite structure and the traditional honeycomb perforated plate structure in the embodiment of the present invention, wherein the black solid line is the sound absorption coefficient of the traditional honeycomb perforated plate structure, the black dotted line is the sound absorption coefficient of the honeycomb perforated plate structure filled with porous materials, and the black dotted line is the sound absorption coefficient of the honeycomb perforated plate sandwich structure filled with porous materials and perforated (embodiment of the present invention).

[0026] Figure 4 The figure is a comparison of the sound absorption coefficients when the perforation diameter d is changed for the honeycomb sandwich perforated plate composite structure in the embodiment of the present invention.

[0027] Figure 5 The figure is a comparison of the sound absorption coefficients when the pore depth h in the filling material is changed for the honeycomb sandwich perforated plate composite structure in the embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a design and manufacturing method for a honeycomb sandwich perforated plate composite structure, which is composed of a back plate, a honeycomb, and a surface skin, wherein the surface skin has perforations 1, the honeycomb cavity is filled with a lightweight material 2, and the filling material in the honeycomb cavity has channels 3 from top to bottom.

[0030] In particular, the holes 3 in the filling material communicate with the surface skin perforations 1 .

[0031] Furthermore, the shape of the honeycomb unit includes but is not limited to being designed as a rectangular, hexagonal, triangular, square or irregular honeycomb, preferably a hexagonal honeycomb.

[0032] Furthermore, the light-weight filling material 2 includes but is not limited to porous materials such as sponge, graphene foam, or titanium dioxide aerogel.

[0033] Furthermore, the pores 3 in the filling material include but are not limited to circular, square, star-shaped, hexagonal or special-shaped, preferably circular.

[0034] The present invention proposes a design of a honeycomb sandwich perforated plate composite structure, and the main principle is as follows: by filling lightweight materials in a traditional honeycomb perforated plate sandwich structure and forming channels in the filling material, the sound absorption mechanism of the porous material is combined with the sound absorption mechanism of the resonant structure, thereby improving the overall sound absorption performance of the structure, and retaining the characteristics of the traditional honeycomb sandwich structure such as light weight and high strength.

[0035] The present invention proposes a method for manufacturing a honeycomb sandwich perforated plate composite structure, which can be well integrated with the traditional honeycomb sandwich structure process. The following briefly describes two manufacturing schemes:

[0036] Technical solution 1, the method comprises the following steps:

[0037] Step 1: Perform bonding and heat treatment on the empty honeycomb and the back plate to connect the two.

[0038] Step 2: Fill the honeycomb cavity with porous materials or lightweight materials such as aerogel.

[0039] Step 3: Surface skinning of the filled honeycomb structure.

[0040] Step 4: Perform a perforation process on the surface skin, and further use the drill bit to penetrate into the honeycomb cavity to form channels in the filled lightweight material.

[0041] Technical solution 2, the method comprises the following steps:

[0042] Step 1: Perform bonding and heat treatment on the empty honeycomb and the back plate to connect the two.

[0043] Step 2: Pre-process the porous material or lightweight material such as aerogel. The shape of the pre-processed lightweight material is a hexagonal prism. The height of the pre-processed lightweight material is less than or equal to the depth of the honeycomb cavity. The pre-processed lightweight material has cylindrical or square channels vertically downward from the center of the upper surface.

[0044] Step 3: Fill the pre-processed lightweight material into the honeycomb cavity.

[0045] Step 4: Skinning the filled honeycomb structure.

[0046] Step 5: Perform perforation process on the surface skin.

[0047] In order to verify the noise reduction performance of the honeycomb sandwich perforated plate composite structure, the sound absorption coefficient of the metamaterial is simulated and calculated using finite element simulation software. The geometric parameters of the structure in the embodiment of the present invention are as follows: Figure 2 As shown, the side length of the honeycomb cavity is L=4.5mm, the depth of the honeycomb cavity is H=20mm, the thickness of the surface skin is t=1mm, the perforation diameter of the surface skin is d=1mm, the channel depth in the filling material is h=5mm, and the channel diameter is consistent with the perforation diameter of the surface skin, which is d=1mm. The filling material is a certain porous material, and the porosity of the filling material is 0.9, the static flow resistivity is 47700Pa S / m^2, the tortuosity is 1.29, the viscosity characteristic factor is 24μm, and the thermal characteristic factor is 200μm.

[0048] The comparison of the sound absorption coefficient between the honeycomb sandwich perforated plate composite structure and the traditional honeycomb sandwich structure is as follows: Figure 3 As shown in the figure, the peak sound absorption frequency of the traditional empty honeycomb perforated plate structure appears at 1080Hz (black solid line). After filling with porous materials, the peak sound absorption frequency moves to low frequency (black dotted line), but the sound absorption peak is reduced. After further perforation in the filling material, the peak frequency of the sound absorption curve moves to low frequency, and the sound absorption peak is higher than the previous two (black dotted line), achieving a higher sound absorption coefficient in a wider frequency range. It is only slightly lower than the honeycomb sandwich structure without perforations in the filling material below 520Hz, indicating that the honeycomb sandwich perforated plate composite structure has better noise reduction performance.

[0049] By changing the perforation diameter of the surface skin and the hole diameter d in the filling material, the acoustic performance of the honeycomb sandwich perforated plate composite structure can be adjusted. Figure 4As shown in the figure, other geometric parameters remain unchanged, and the peak sound absorption frequency moves toward high frequency with the increase of the perforation diameter d, from 860 Hz (black solid line, d = 1 mm) to 1000 Hz (black dashed line, d = 1.2 mm), and further to 1220 Hz (black dotted line, d = 1.6 mm). The sound absorption peak value gradually increases, and the sound absorption performance can be adjusted in a wide frequency range.

[0050] In addition, changing the channel depth h in the filling material can affect the acoustic performance of the honeycomb sandwich perforated plate composite structure. The sound absorption coefficient corresponding to changing the channel depth h is as follows: Figure 5 As shown, while other geometric parameters remain unchanged, the sound absorption peak moves from 83% (black solid line, h=5 mm) to 81% (black dashed line, h=2 mm), and further moves to 78% (black dotted line, h=1 mm), and the sound absorption peak decreases slightly.

[0051] In this embodiment, the diameter of the hole in the filling material is consistent with the perforation diameter d of the surface skin. In practical applications, the two may take different values.

[0052] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A design and manufacturing method of a honeycomb sandwich perforated plate composite structure, characterized in that: It is composed of a back plate, a honeycomb, a filling material, and a surface skin. The honeycomb is located above the back plate and connected to the back plate. The honeycomb contains a filling material, and the filling material has channels from top to bottom. The surface skin is located above the honeycomb and connected to the honeycomb, and the surface skin has perforations.

2. The design and manufacturing method of a honeycomb sandwich perforated plate composite structure according to claim 1, characterized in that: The channels in the filling material are connected with the perforations in the surface skin. The cross-sectional shape of the channels in the filling material includes but is not limited to being designed as rectangles, hexagons, triangles, squares or irregular shapes. The diameter of the channels in the filling material and the diameter of the perforations in the surface skin may take different values.

3. The design and manufacturing method of a honeycomb sandwich perforated plate composite structure according to claim 1, characterized in that: The filling material is a light material such as sponge, graphene foam, aerogel, etc.

4. The design and manufacturing method of a honeycomb sandwich perforated plate composite structure according to claim 1, characterized in that: It includes the following two technical solutions: Technical solution 1, the method comprises the following steps: Step 1: Perform bonding and heat treatment on the empty honeycomb and the back plate to connect the two. Step 2: Fill the honeycomb cavity with porous materials or lightweight materials such as aerogel. Step 3: Surface skinning of the filled honeycomb structure. Step 4: Perform a perforation process on the surface skin, and further use a drill bit to penetrate into the honeycomb cavity to form channels in the filled lightweight material. The depth of the channel can be accurately controlled by CNC and other processes. Technical solution 2, the method comprises the following steps: Step 1: Perform bonding and heat treatment on the empty honeycomb and the back plate to connect the two. Step 2: Pre-process the porous material or lightweight material such as aerogel. The shape of the pre-processed lightweight material is a hexagonal prism. The height of the pre-processed lightweight material is less than or equal to the depth of the honeycomb cavity. The pre-processed lightweight material has cylindrical or square channels vertically downward from the center of the upper surface. Step 3: Fill the pre-processed lightweight material into the honeycomb cavity. Step 4: Skinning the filled honeycomb structure. Step 5: Perform perforation process on the surface skin.

5. The design and manufacturing method of a honeycomb sandwich perforated plate composite structure according to claim 1, characterized in that: The pore diameter and pore depth in the filling material can be adjusted.

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