Shock-resistant, sound-absorbing and noise-reducing lattice superstructure

Abstract

The invention relates to the technical field of sound absorption and noise reduction, in particular to an anti-impact sound absorption and noise reduction lattice superstructure which comprises an array formed by connecting a plurality of sound absorption cavities, each sound absorption cavity is a truncated octahedron formed by a plurality of panels, and the panels comprise eight regular hexagonal panels and six quadrilateral panels. The two adjacent edges of every two adjacent panels are connected through a hollow truss, and a micro hole is formed in the center of each panel. According to the adjustable Helmholtz resonator, the hollow structure is introduced, stress concentration at truss nodes is effectively reduced, the panels are arranged between the adjacent trusses, an internal air phase is constructed through the micropore design, the sound absorption frequency band of the structure is widened, the sound impedance of the structure can be adjusted through the micropores, and therefore the multiple complete adjustable Helmholtz resonators are formed; when the frequency of incident sound waves is close to the inherent frequency of the resonator, the air columns in the micropores generate strong vibration, sound energy is consumed due to the thermal viscosity effect, and the sound absorption and noise reduction structure can have good sound absorption and energy absorption effects while having good mechanical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of sound absorption and noise reduction, and particularly to an impact-resistant sound absorption and noise reduction lattice superstructure. Background Art

[0002] In many engineering fields such as aerospace, rail transit, ships, and building manufacturing, the coupled requirements of noise control and load-bearing impact resistance for service equipment are significant. While maintaining lightweight, the structure / material not only needs to eliminate and suppress noise, reduce the harm of noise, but also provide excellent mechanical strength and energy absorption performance. However, under the constraints of lightweight and small-size space, it is still a major technical difficulty to achieve the multi-function and high-performance of materials / structures. For example, low density is difficult to provide ideal mechanical response, and small size limits the sound absorption efficiency to a certain extent. Among existing sound absorption structures, both metamaterial structures and porous materials have good sound absorption performance, but their mechanical properties are poor, resulting in their limited application in many scenarios. In the field of acoustics, compared with traditional sound absorption materials (foams, fabrics, and perforated plates) and mainstream acoustic metamaterials, micro-lattices have advantages such as structural rigidity, mechanical robustness, and structural customizability. However, in contrast, the sound absorption performance of micro-lattices is still limited by narrow bandwidth, low sound absorption coefficient, or both. That is to say, the structures of the existing technologies cannot simultaneously possess mechanical properties as well as sound absorption and energy absorption functions. Summary of the Invention

[0003] In order to overcome the technical problem that the sound absorption structures in the existing technologies cannot simultaneously possess mechanical properties as well as sound absorption and energy absorption functions, the present invention provides an impact-resistant sound absorption and noise reduction lattice superstructure.

[0004] The technical solution adopted by the present invention to achieve the above object is: an impact-resistant sound absorption and noise reduction lattice superstructure, characterized in that it includes an array formed by connecting a plurality of sound absorption cavities. The sound absorption cavity is a truncated octahedron formed by multiple panels. The panels include eight regular hexagonal panels and six quadrilateral panels. Adjacent sides of adjacent two panels are connected by hollow trusses. A micropore is provided at the center of each panel.

[0005] Preferably, the sound absorption cavities are connected by connecting struts.

[0006] Preferably, the six quadrilateral panels include two square panels at the top and bottom, and four rhombic panels around. The hollow trusses at the intersection of the upper and lower vertices of each rhombic panel and the regular hexagonal panel are connected to the connecting struts.

[0007] Preferably, the included angle between the connecting strut and its corresponding rhombic panel is 0° to 90°.

[0008] Preferably, the connecting strut is a hollow cylinder.

[0009] Preferably, the ratio of the outer diameter of the hollow truss to the side length of the panel is 15-25:20-32.

[0010] Preferably, the diameter of the micropores is 0.3 mm - 0.8 mm.

[0011] Compared with the prior art, the beneficial effects of the present invention are that the introduction of the hollow structure effectively reduces the stress concentration at the truss joints. At the same time, there are panels between adjacent trusses of the hollow truncated octahedron truss lattice structure, and the micropore design constructs an internal air phase, broadening the sound absorption frequency band of the structure. Opening micropores can adjust the acoustic impedance of the structure, thus forming multiple complete adjustable Helmholtz resonators. When the frequency of the incident sound wave approaches the natural frequency of the resonator, the air column inside the micropores generates strong vibrations, and the sound energy is consumed due to the thermo-viscous effect, achieving a high sound absorption effect. It enables the sound absorption and noise reduction structure to have good mechanical properties while also having good sound absorption and energy absorption effects. Description of the Drawings

[0012] Figure 1 is a partial structural diagram of an impact-resistant, sound-absorbing and noise-reducing lattice superstructure of the present invention.

[0013] Figure 2 is a structural diagram of the sound absorption cavity of an impact-resistant, sound-absorbing and noise-reducing lattice superstructure of the present invention.

[0014] Figure 3 is of the present invention Figure 2 a cross-sectional view along the horizontal center line.

[0015] Figure 4 is of the present invention Figure 2 a cross-sectional view along the vertical center line.

[0016] Figure 5 is a schematic diagram of the air domain at the sound absorption unit of an impact-resistant, sound-absorbing and noise-reducing lattice superstructure of the present invention.

[0017] Figure 6 is a structural diagram of the sound absorption cavity of Comparative Example 1 of the present invention.

[0018] Figure 7 is a structural diagram of the sound absorption cavity of Comparative Example 2 of the present invention.

[0019] Figure 8 is a compression performance curve graph of the structures of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0020] Figure 9 is a comparison graph of the specific energy absorption results of the structures of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0021] Figure 10 is a graph showing the change of the sound absorption coefficient of the structures of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention with the frequency of the incident sound wave.

[0022] In the figure: 1. Sound absorption cavity; 101. Regular hexagon panel; 102. Square panel; 103. Rhombus panel; 104. Hollow truss; 105. Micro-hole; 2. Connecting strut. Specific implementation mode

[0023] Embodiment 1: The specific implementation mode of a shock-resistant sound absorption and noise reduction lattice superstructure of the present invention is as Figures 1-10 shown, including a matrix formed by connecting a number of sound absorption cavities 1 through connecting struts 2. The connecting struts 2 are hollow cylinders. The sound absorption cavity 1 is an truncated octahedron formed by multiple panels. The panels include eight regular hexagon panels 101 and six quadrilateral panels. Adjacent sides of adjacent two panels are connected through hollow trusses 104. Each panel is provided with a micro-hole 105 at the center. Among them, the six quadrilateral panels include two square panels 102 at the top and bottom and four rhombus panels 103 around. The hollow truss 104 at the intersection of the upper and lower two vertices of each rhombus panel 103 and the regular hexagon panel 101 is connected to the connecting strut 2, and the included angle between the connecting strut 2 and its corresponding rhombus panel 103 is 45°. The ratio of the outer diameter of the hollow truss 103 to the side length of the panel is 15:20. In this embodiment, the outer diameter of the hollow truss 103 is 1.5 mm, the inner diameter is 0.8 mm, the side length of the panel is 2 mm, and the diameter of the micro-hole 105 is 0.3 mm. The above-mentioned shock-resistant sound absorption and noise reduction lattice superstructure is prepared by laser powder bed fusion preparation technology. The material is AlSi10Mg, and its manufacturing process parameters can be: the powder particle size is 20 - 50 μm, the scanning speed is 1400 mm / s, the laser power is 325 W, and the printing thickness is 30 μm.

[0024] Embodiment 2: This embodiment is generally the same as Embodiment 1, except that the ratio of the outer diameter of the hollow truss 103 to the side length of the panel is 20:26, the included angle between the connecting strut 2 and its corresponding rhombus panel 103 is 80°, and the diameter of the micro-hole is 0.5 mm.

[0025] Embodiment 3: This embodiment is generally the same as Embodiment 1, except that the ratio of the outer diameter of the hollow truss 103 to the side length of the panel is 25:32, the included angle between the connecting strut 2 and its corresponding rhombus panel 103 is 10°, and the diameter of the micro-hole is 0.8 mm.

[0026] Comparative Example 1: As Figure 6 shown, the structure is generally the same as that of Embodiment 1, except that the sound absorption cavity is an truncated octahedron formed by solid trusses and there is no panel.

[0027] Comparative Example 2: As Figure 7As shown, the structure is generally the same as that of Embodiment 1, except that the sound absorption cavity is an octahedron with truncated corners formed by a hollow truss and there is no panel.

[0028] The compression performance of the lattice superstructure of Embodiment 1 and the structures of Comparative Example 1 and Comparative Example 2 was compared, and the obtained compression performance curves are as Figure 8 shown. It can be seen from Figure 8 that the crushing force of the lattice superstructure of Embodiment 1 is significantly greater than that of Comparative Example 1 and Comparative Example 2, indicating that it has better mechanical properties.

[0029] The lattice superstructure of Embodiment 1 and the structures of Comparative Example 1 and Comparative Example 2 were subjected to quasi-static compression energy absorption tests through a universal testing machine at a crushing speed of 5 mm / min, and the obtained energy absorption characteristic results are as Figure 9 shown. The specific energy absorption of Embodiment 1 reached 37.29 kJ / kg, which was 10.1% higher than that of Comparative Example 1 and 20.2% higher than that of Comparative Example 2. It can be seen that the lattice superstructure of Embodiment 1 has a better energy absorption effect.

[0030] The lattice superstructure of Embodiment 1 and the structures of Comparative Example 1 and Comparative Example 2 were subjected to sound absorption coefficient tests through an acoustic impedance tube test system. The curves of the sound absorption coefficients of the three structures varying with the incident sound wave frequency are as Figure 10 shown. It can be seen from Figure 10 that the lattice superstructure of Embodiment 1 reached the sound absorption coefficient peak value of 0.95 at 1210 Hz, the frequency with a sound absorption coefficient above 0.5 was from 870 Hz to 4010 Hz, and the half absorption bandwidth was 3140 Hz, successfully achieving broadband sound absorption; the average value of the sound absorption coefficient of the lattice superstructure of Embodiment 1 was 6.27 times higher than the average value of the sound absorption coefficient of Comparative Example 2 and 8.27 times higher than the average value of the sound absorption coefficient of Comparative Example 1, and the sound absorption effect was greatly improved. In summary, the lattice superstructure of Embodiment 1 has good mechanical properties, energy absorption effect and sound absorption effect.

[0031] Working principle: The micro-holes 105 on the panel and the internal cavity combine to form a Helmholtz resonator. The internal cavity provides capacitance for the system, and opening the micro-holes 105 mainly adjusts the acoustic impedance of the structure, thus constituting multiple complete adjustable Helmholtz resonators. The air domain inside the resonator structure is as Figure 5 shown. When the frequency of the incident sound wave approaches the natural frequency of the resonator, the internal air column of the opening generates strong vibrations, and the sound energy is consumed due to thermo-viscous effects, achieving a high sound absorption effect. It can be used in combination with building boards to make noise-reducing building boards.

[0032] The present invention is described by way of examples, and those skilled in the art will appreciate that various changes or equivalent substitutions can be made to these features and examples without departing from the spirit and scope of the present invention. Additionally, under the teachings of the present invention, these features and examples can be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the protection scope of the present invention.

Claims

1. An impact-resistant, sound-absorbing and noise-reducing lattice superstructure, characterized in that, An array formed by connecting several sound-absorbing cavities (1), the sound-absorbing cavity (1) being a truncated octahedron formed by multiple panels, the panels including eight regular hexagonal panels (101) and six quadrilateral panels, adjacent sides of adjacent two panels being connected by hollow trusses (104), and each panel having a micropore (105) opened at its center.

2. The impact-resistant, sound-absorbing and noise-reducing lattice superstructure according to claim 1, wherein The sound-absorbing cavities (1) are connected by connecting struts (2).

3. The impact-resistant, sound-absorbing and noise-reducing lattice superstructure according to claim 1, wherein The six quadrilateral panels include two square panels (102) at the top and bottom, and four rhombic panels (103) around. The hollow trusses (104) at the joints of the upper and lower vertices of each rhombic panel with the regular hexagonal panels (101) are connected to the connecting struts (2).

4. The impact-resistant, sound-absorbing and noise-reducing lattice superstructure according to claim 3, characterized in that The included angle between the connecting strut (2) and its corresponding rhombic panel (103) is 0° to 90°.

5. The impact-resistant, sound-absorbing and noise-reducing lattice superstructure according to claim 2, characterized in that, The connecting strut (2) is a hollow column.

6. The impact-resistant, sound-absorbing and noise-reducing lattice superstructure according to claim 1, characterized in that The ratio of the outer diameter of the hollow truss (104) to the side length of the panel is 15 - 25:20 - 32.

7. The impact-resistant, sound-absorbing and noise-reducing lattice superstructure according to claim 1, wherein The diameter of the micropore (105) is 0.3 mm - 0.8 mm.

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