Honeycomb sandwich panel structure with vibration isolation and micro-vibration functions and preparation method

Abstract

The invention discloses a honeycomb sandwich panel structure with vibration isolation and micro vibration and a preparation method thereof, and belongs to the technical field of low-frequency vibration isolation, the honeycomb sandwich panel structure comprises a plurality of unit cell groups arranged from top to bottom, and each unit cell group comprises N rows and M columns of unit cells; each unit cell comprises a honeycomb tubular structure with an upper opening and a lower opening; the lower panel and the lower panel are correspondingly and fixedly connected with an upper opening and a lower opening of the honeycomb tubular structure respectively, so that the lower panel and the honeycomb tubular structure jointly form a honeycomb core with a cavity inside; the local resonator is arranged in the cavity of the honeycomb core and comprises an elastic part and a mass block which are connected, the elastic part is connected with the upper panel or the lower panel, and the mass block does not make contact with the upper panel and the lower panel. On the basis of a local resonance mechanism, the local resonators are added into the gaps of the honeycomb sandwich layer, so that low-frequency vibration isolation is achieved, meanwhile, the size is small, the mass is light, and meanwhile the strict requirement for multi-span working frequency under numerous complex working conditions at present is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-frequency vibration isolation, and more specifically, relates to a honeycomb sandwich panel structure with vibration isolation for micro-vibrations and a preparation method thereof. Background Art

[0002] With the progress and development of the times, people have put forward higher requirements for aerospace technology. The performance requirements of high resolution and high stability make the working components more demanding on the working environment and the system more sensitive. At the same time, the development of high-precision and high-resolution remote sensing earth observation satellites and other aerospace vehicles is extremely important for national security, social stability and economic development. It is a field that countries around the world are competing for and is also the only way for the development of aerospace vehicles in our country.

[0003] In high-resolution remote sensing earth observation satellites, honeycomb sandwich panels constitute the main cabin structure and carry optical instruments for observation. Although honeycomb sandwich panels have advantages such as high specific strength, light weight, and high specific stiffness. However, when the honeycomb sandwich panel is excited to vibrate, its own vibration isolation performance is almost zero. But due to the existence of many disturbance sources in the remote sensing earth observation satellite itself, such as the micro-vibration elastic waves generated by the dynamic and static unbalances of the internal rotor of the control moment gyro (CMG) propagating through the honeycomb sandwich panel, affecting the imaging accuracy of the optical instruments it carries.

[0004] Currently, the effective working range of traditional vibration isolation devices is mostly in the range of several hundred to several thousand hertz or more, and they cannot achieve true low frequency. Some structures that can achieve low frequency have the disadvantages of large size and large mass and cannot be applied to actual engineering. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the present invention provides a honeycomb sandwich panel structure with vibration isolation for micro-vibrations and a preparation method thereof, aiming to solve the technical problem that existing vibration isolation devices cannot balance low-frequency vibration isolation and small volume.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided a honeycomb sandwich panel structure with vibration isolation for micro-vibrations, including: a plurality of unit cell groups arranged from top to bottom, each of the unit cell groups including N rows and M columns of unit cells; each of the unit cells including:

[0007] A honeycomb tubular structure with upper and lower openings;

[0008] A lower panel and an upper panel, respectively fixedly connected to the upper and lower openings of the honeycomb tubular structure to jointly form a honeycomb core with a cavity inside together with the honeycomb tubular structure;

[0009] Local resonators are arranged in the cavities of the honeycomb core and include an elastic member and a mass block connected thereto, and the elastic member is connected to the upper panel or the lower panel, and the mass block does not contact the upper panel and the lower panel.

[0010] Further, the local resonator includes, from top to bottom: a flexible rubber strip and a mass block suspended therefrom, the flexible rubber strip is fixedly connected to the upper panel, and the mass block is at a certain distance from the lower panel.

[0011] Further, the local resonator includes, from top to bottom: the mass block and a tower spring connected thereto, the tower spring is fixedly connected to the lower panel, and the tower spring is at a certain distance from the upper panel.

[0012] Further, the natural frequencies of the local resonators in the same row of the single cells in each single cell group are the same; the natural frequencies of the local resonators in the same column increase sequentially.

[0013] Further, the natural frequency of the local resonator in the nth row and the ith column is (n ∈ [1, N], i ∈ [1, M]), where k is the equivalent stiffness of the elastic member and m is the mass of the mass block in the single cell in the nth row and the ith column.

[0014] Further, the higher the vibration isolation frequency band to be achieved, the more single cells are longitudinally selected in each single cell group.

[0015] Further, if the frequency band to be achieved is on the order of dozens of Hz, the number of longitudinally selected single cells is 2 or 3; if the frequency band to be achieved is on the order of hundreds of Hz, the number of longitudinally selected single cells is 4 / 5; if the frequency band to be achieved is on the order of thousands of Hz, the number of longitudinally selected single cells is about 10.

[0016] According to another aspect of the present invention, there is provided a method for manufacturing a honeycomb sandwich panel structure with vibration isolation for micro-vibrations, including:

[0017] S1: Fabricate the honeycomb tubular structure of each single cell;

[0018] S2: Bond a panel at one end of the honeycomb tubular structure;

[0019] S3: Bond the elastic member to the mass block to form a local resonator;

[0020] S4: Bond the local resonator to the panel so that it is in the cavity of the honeycomb sandwich structure;

[0021] S5: Paste another panel at the other end of the honeycomb tubular structure to obtain a single cell;

[0022] S6: Paste multiple unit cells together to form a group of unit cells, and arrange multiple groups of unit cells from top to bottom to obtain a honeycomb sandwich panel structure with vibration isolation for micro-vibrations.

[0023] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0024] (1) The present invention provides a honeycomb sandwich panel structure with vibration isolation for micro-vibrations. Utilizing the characteristic that the periodicity of the honeycomb sandwich panel is consistent with that of the phononic crystal, without changing the mechanical properties of the honeycomb sandwich panel structure, local resonators are introduced into the honeycomb sandwich panel, so that the satellite is not affected when adjusting the satellite attitude through the CMG, and the local resonators resonate at their natural frequencies to effectively isolate micro-vibrations below 150 Hz. Based on the local resonance mechanism, local resonators are added to the voids of the honeycomb core layer to achieve low-frequency vibration isolation while being small in volume and light in mass, and at the same time to meet the stringent requirements of multi-span working frequencies under numerous complex working conditions. All in all, the present invention is a honeycomb sandwich panel structure with low frequency and high performance for vibration isolation of micro-vibrations, which can overcome the deficiencies of large volume, large mass, and poor low-frequency vibration isolation performance in the past, so it can have the characteristics of both low-frequency broadband vibration isolation and millimeter-scale size, and has excellent low-frequency broadband vibration isolation performance.

[0025] (2) This solution introduces a tower-shaped spring. Through the non-linear stiffness characteristic of the tower-shaped spring, different natural frequencies are achieved, thereby broadening the local resonance bandgap to achieve low-frequency broadband micro-vibration isolation.

[0026] (3) This solution generates local resonators with different natural frequencies, and through the vibration coupling effect between local resonators with different natural frequencies, a low-frequency vibration isolation phononic crystal type honeycomb sandwich panel with a wider working frequency band is obtained. By forming a wider phononic crystal bandgap, within the bandgap range of the phononic crystal, elastic waves cannot propagate well, which has a good vibration isolation effect on low-frequency broadband. Description of the Drawings

[0027] Figure 1 Schematic diagram of a honeycomb sandwich panel structure with vibration isolation for micro-vibrations provided by Embodiment 1 of the present invention;

[0028] Figure 2 Cross-sectional view of a honeycomb sandwich panel structure with vibration isolation for micro-vibrations provided by Embodiment 1 of the present invention;

[0029] Figure 3 Schematic diagram of a unit cell of a honeycomb sandwich panel structure with vibration isolation for micro-vibrations provided by Embodiment 1 of the present invention;

[0030] Figure 4The front view of a unit cell of a honeycomb sandwich panel structure with vibration isolation and micro-vibration provided in Embodiment 1 of the present invention;

[0031] Figure 5 The design schematic diagram of the fixed frequency in a honeycomb sandwich panel structure with vibration isolation and micro-vibration provided in Embodiment 1 of the present invention.

[0032] In all the drawings, the same reference numerals are used to represent the same elements or structures, where:

[0033] 1 is the unit cell; 2 is the outer frame; 3 is the cavity; 4 is the panel; 5 is the glue layer; 6 is the local resonator; 6-1 is the tower spring; 6-2 is the mass block. Detailed implementation manners

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. 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. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Embodiment 1

[0036] This embodiment provides a honeycomb sandwich panel structure with vibration isolation and micro-vibration, including: a plurality of unit cell groups arranged from top to bottom, each of the unit cell groups including N rows and M columns of unit cells; each of the unit cells including: a honeycomb tubular structure, an upper panel and a lower panel, and a local resonator; wherein, the honeycomb tubular structure has openings at both the top and the bottom; the upper panel and the lower panel are respectively fixedly connected to the upper and lower openings of the honeycomb tubular structure to jointly form a honeycomb core with a cavity inside; the local resonator is arranged in the cavity of the honeycomb core and includes: an elastic component and a mass block connected thereto, and the elastic component is connected to the upper panel or the lower panel, and the mass block does not contact the upper panel and the lower panel.

[0037] As Figure 1 shown, this embodiment is formed by periodically arranging and combining a plurality of unit cells. As Figures 2 to 4 shown, it includes: each unit cell 1 includes an outer frame 2, a panel 4, a glue layer 5 for fixing, a cavity 3 located between the two glue layers 5 and inside the outer frame 2, and a local resonator 6 located in the cavity 3.

[0038] The external frame 2 is a hollow straight tube with openings at the top and bottom. Its shape can be hexagonal, quadrilateral, rectangular, etc. The material of the external frame 2 can be composite materials such as carbon fiber tubes or metal materials such as aluminum alloy, stainless steel, and red copper. Among them, the external frame 2 can be selected for the production method according to the size. It can be obtained by 3D printing or by hot pressing and bonding. In this example, it is selected to be obtained by hot pressing and bonding. Its external frame 2 is hexagonal in shape. Because the working environment is space, the material is selected as aluminum alloy, with a thickness of 0.05 mm, a height of 30 mm, and an inscribed circle radius of 30 mm;

[0039] The cavity 3 is located between the two glue layers 5 and inside the external frame 2. The formed internal space is mainly to provide a limited space for the oscillator to resonate, and sufficient displacement space needs to be reserved. Its space height is 30 mm, and the inscribed circle radius is 30 mm;

[0040] The panel 4 is bonded to the top and bottom ends of the external frame 2 through the glue layer 5. The panel material can be selected as composite materials such as carbon fiber boards or metal materials such as aluminum alloy plates. It is mainly used to bear the shear force of the honeycomb sandwich panel. In this embodiment, the panel material is selected to be the same as the external frame, both are aluminum alloy materials. The panel thickness is 0.3 mm, the panel is square in shape, and its side length is 0.8 m;

[0041] The glue layer 5 is located between the external frame 2 and the panel 4, mainly to strengthen the connection between the two and increase its strength. The glue layer can use modified acrylic AB glue or epoxy resin, which is heated and stirred after being mixed in a weight ratio of 1:1 with the curing agent. In this embodiment, the adopted is modified acrylic AB glue, and its thickness is 0.15 mm;

[0042] Further, the local resonator includes, from top to bottom: a flexible rubber strip and the mass block suspended by it. The flexible rubber strip is fixedly connected to the upper panel, and there is a certain distance between the mass block and the lower panel.

[0043] Further, the local resonator includes, from top to bottom: the mass block and the tower spring connected to it. The tower spring is fixedly connected to the lower panel, and there is a certain distance between the tower spring and the upper panel.

[0044] For example, the local resonator 6 is located within the cavity 3 and mainly consists of a tower-shaped spring 6-1 and a mass block 6-2. The central axes of both are coaxial with the central axis of the unit cell 1. The fixing method between the tower-shaped spring 6-1 and the mass block 6-2 can adopt modified acrylic AB glue, 502 glue, welding or physical methods. The density of different mass blocks can be selected differently, or mass blocks of different volumes can be adopted. After the tower-shaped spring 6-1 and the mass block 6-2 are fixed together, they can be bonded to the glue layer through a similar modified acrylic AB glue. In this embodiment, the pitch of the tower-shaped spring 6-1 of the local resonator 6 is 1.5 mm, the number of turns is 10, the length is 15 mm, the bottom radius is 10 mm, the upper end radius is 5 mm, and the radius of the tower-shaped spring 6-1 is 0.5 mm; the material of the mass block is selected as brass metal material, the radius is 6 mm, and the height is 10 mm. The fixing method between the two is selected as modified acrylic AB glue, and it is arranged in the cavity 3, and a displacement space of 5 mm is reserved for it in the vertical direction.

[0045] Furthermore, the natural frequencies of the local resonators in the unit cells in the same row within each unit cell group are the same; the natural frequencies of the local resonators in the same column increase sequentially, as Figure 5 shown, where there are three rows of unit cells in each unit cell group, that is, M = 3. The fixed frequencies of the individual unit cells in each row are the same and increase sequentially from top to bottom, ω1 < ω2 < ω3.

[0046] Furthermore, the natural frequency of the local resonator in the nth row and the ith column is (n ∈ [1, N], i ∈ [1, M]), k is the equivalent stiffness of the elastic component, and m is the mass of the mass block within the unit cell in the nth row and the ith column.

[0047] Furthermore, the higher the vibration isolation frequency band to be achieved, the more unit cells are longitudinally selected within each unit cell group.

[0048] Furthermore, if the frequency band to be achieved is on the order of dozens of Hz, the number of unit cells longitudinally selected is 2 or 3; if the frequency band to be achieved is on the order of hundreds of Hz, the number of unit cells longitudinally selected is 4 / 5; if the frequency band to be achieved is on the order of thousands of Hz, the number of unit cells longitudinally selected is about 10.

[0049] Embodiment 2

[0050] This embodiment provides a design method for a honeycomb sandwich panel structure with vibration isolation and micro-vibration, including: S1: fabricating the honeycomb tubular structure of each unit cell; S2: bonding a faceplate at one end of the honeycomb tubular structure; S3: bonding an elastic component to a mass block to form a local resonator; S4: bonding the local resonator to the faceplate so that it is in the cavity of the honeycomb sandwich structure; S5: pasting another faceplate at the other end of the honeycomb tubular structure to obtain a unit cell; S6: pasting a plurality of unit cells together to form a unit cell group, and arranging a plurality of unit cell groups from top to bottom to obtain a honeycomb sandwich panel structure with vibration isolation and micro-vibration.

[0051] The following is a detailed process for exemplifying this preparation method. The specific numerical values are only for illustration and are not strictly limited. In actual applications, the values can be adjusted according to the scenario.

[0052] S1. Fabricate the outer frame 2: Determine the size of the unit cell 1 according to the vibration isolation frequency. In this embodiment, the outer frame is hexagonal, where the thickness of the hexagonal tubular structure is 0.05 mm, the height is 30 mm, and the inradius is 30 mm. It is obtained by hot pressing and bonding, and the material is selected as aluminum alloy.

[0053] S2. Seal one side of the outer frame 2: The glue layer 5 uses a modified acrylic AB glue or epoxy resin, which is heated and stirred after being mixed in a weight ratio of 1:1 of the curing agent. Bond a faceplate at one end of the outer frame. In this embodiment, a modified acrylic AB glue is used to bond the single-layer faceplate 4 to the outer frame 2 for convenient subsequent operations. The glue layer is 0.15 mm, the faceplate thickness is 0.3 mm, the faceplate is square in shape, and its side length is 0.8 m.

[0054] S3. Fabricate the local resonator 6: Taking the elastic component as a tower spring as an example for description. If it is a flexible rubber strip, the process can be deduced equivalently. Bond the tower spring 6-1 to the mass block 6-2 through a modified acrylic AB glue or fix it by physical methods to form a local resonator. The central axes of both are arranged coaxially with the central axis of the unit cell 1. In this embodiment, a modified acrylic AB glue is used to fix the two. After mixing A glue and B glue in a ratio of 1:1, it is evenly applied at the connection of the two and left standing for 24 h to reach the highest service strength. The length of the tower spring is 15 mm, the bottom radius is 10 mm, the upper radius is 5 mm, the radius of the tower spring is 0.5 mm, the height of the mass block is 10 mm, and the radius is 6 mm.

[0055] S4. Bond the local resonator 6: Bond the local resonator to the panel with a modified acrylic AB glue so that it is inside the cavity of the honeycomb sandwich structure. Leave a distance of 5 mm from the mass block to the other panel 4. After mixing A glue and B glue in a ratio of 1:1, apply it to the bottom of the tower spring 6-1 and let it stand for 24 h to reach the highest working strength.

[0056] S5. Outer frame 2 of the cover: The glue layer uses a modified acrylic AB glue or epoxy resin, which is made by mixing the curing agent in a weight ratio of 1:1 and heating and stirring. Bond the outer frame 2 of the aluminum honeycomb core at the other end to another panel. The thicknesses of the upper and lower glue layers are the same, both being 0.15 mm.

[0057] It should be noted that when it is in the working frequency band, two modes are used to open its local resonance band gap respectively. One is mainly the vibration mode of the oscillator swinging up and down, and the other is the vibration mode completely opposite to the previous one, which is described as the oscillator hardly moving and the homogeneous solid and the panel vibrating up and down as a whole. The mass block 6-2 vibrates up and down, and the energy input from the outside is gradually dissipated through the vibration of the local resonator. At the same time, the tower spring 6-1 is compressed. Since the displacement of the swing generated at different frequencies is different, the tower spring produces different deformations, thus forming different stiffnesses k, and thus generating local resonators with different natural frequencies. By coupling the vibrations between the local resonators with different natural frequencies, a low-frequency vibration isolation phononic crystal type honeycomb sandwich panel with a wider working frequency band is obtained. At the same time, in the resonance of the local resonator, within the band gap frequency band, elastic waves cannot propagate well, so good low-frequency broadband vibration isolation is achieved.

[0058] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A honeycomb sandwich panel structure with vibration isolation and micro-vibration, characterized in that, Comprising: A plurality of unit cell groups arranged from top to bottom, each of the unit cell groups including N rows and M columns of unit cells; Each of the unit cells includes: A honeycomb tubular structure with upper and lower openings; An upper panel and a lower panel, respectively fixedly connected to the upper and lower openings of the honeycomb tubular structure to jointly form a honeycomb core with a cavity inside together with the honeycomb tubular structure; A local resonance element, disposed in the cavity of the honeycomb core, including: an elastic member and a mass block connected thereto, and the elastic member is connected to the upper panel or the lower panel, and the mass block does not contact the upper panel and the lower panel.

2. The honeycomb sandwich panel structure according to claim 1, characterized in that, The local resonance element from top to bottom includes: a flexible rubber strip and a mass block suspended therefrom, the flexible rubber strip is fixedly connected to the upper panel, and the mass block has a certain distance from the lower panel.

3. The honeycomb sandwich panel structure according to claim 1, characterized in that, The local resonance element from top to bottom includes: the mass block and a tower-shaped spring connected thereto, the tower-shaped spring is fixedly connected to the lower panel, and the tower-shaped spring has a certain distance from the upper panel.

4. The honeycomb sandwich panel structure according to claim 1, characterized in that, The natural frequencies of the local resonance elements in the unit cells of the same row in each of the unit cell groups are the same; the natural frequencies of the local resonance elements in the same column increase in sequence.

5. The honeycomb sandwich panel structure according to claim 4, characterized in that, The natural frequency of the local resonator at the n-th row and the i-th column is where k is the equivalent stiffness of the elastic component, and m is the mass of the mass block in the unit cell at the n-th row and the i-th column.

6. The honeycomb sandwich panel structure according to claim 4, wherein, The higher the vibration isolation frequency band to be achieved, the more unit cells are longitudinally selected in each of the unit cell groups.

7. The honeycomb sandwich panel structure according to claim 6, wherein If the frequency band to be achieved is on the order of dozens of Hz, the number of unit cells longitudinally selected is 2 or 3; If the frequency band to be achieved is on the order of hundreds of Hz, the number of unit cells longitudinally selected is 4 / 5; If the frequency band to be achieved is on the order of thousands of Hz, the number of unit cells longitudinally selected is about 10.

8. A preparation method of a honeycomb sandwich panel structure with vibration isolation and micro-vibration, characterized in that, Comprising: S1: Fabricating the honeycomb tubular structure of each unit cell; S2: Bonding a panel at one end of the honeycomb tubular structure; S3: Bonding the elastic member to the mass block to form a local resonance element; S4: Bonding the local resonance element to the panel so that it is in the cavity of the honeycomb sandwich structure; S5: Pasting another panel at the other end of the honeycomb tubular structure to obtain a unit cell; S6: Pasting a plurality of unit cells together to form a unit cell group, and arranging a plurality of unit cell groups from top to bottom to obtain a honeycomb sandwich panel structure with vibration isolation for micro-vibrations.

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