Micro-perforated truss sandwich sound insulation and absorption composite system

Abstract

The invention discloses a micro-perforated truss sandwich sound insulation and absorption composite system, which belongs to the technical field of engineering vibration and noise reduction, and comprises a plurality of groups of tile type scattering layers, truss sandwich structure units and tile type gathering and emitting layers which are arranged in an array, the tile type scattering layer comprises a first closed arc-shaped frame, a first internal supporting truss, a micropore array and a rigid pipeline; each truss sandwich structure unit comprises a cavity, plain cloth micropores, a truss structure frame, an internal resonance mechanism and a connecting plate; the tile type gathering and injecting layer comprises a second closed arc-shaped frame and a second internal supporting truss; the truss sandwich structure unit and the tile type scattering layer are arranged in the same direction, and the tile type focusing layer and the tile type scattering layer are arranged in an orthogonal mode. According to the invention, the truss structure, the tile structure and the Helmholtz resonance structure are comprehensively utilized, and the sound insulation and absorption capability and the deformation resistance capability are prominent.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering vibration reduction and noise reduction, and particularly relates to a micro-perforated truss sandwich sound insulation and absorption composite system. Background Art

[0002] At present, the total mileage of high-speed railways in China has exceeded 45,000 kilometers. With the planning and construction of more high-speed railway lines between cities, the driving mileage of high-speed railways will further increase. However, when taking high-speed trains such as high-speed rail bullet trains, due to the friction between the vehicle body shell and the outside air, a turbulent boundary layer is formed, causing the vehicle body to generate strong random vibration noise. Among them, the sound with a frequency range of 20 Hz - 4000 Hz has a serious impact on the residents located near the transportation line. To solve the problem of noise annoyance, an excellent sound insulation and absorption system is needed.

[0003] The sandwich structure is a commonly used sound-absorbing material, and the sound absorption effect can be achieved by controlling the hole shape and arrangement of the sandwich layer. Traditional sandwich structures have certain limitations in terms of frequency response range, sound absorption performance, and mechanical properties. The sandwich structure may be excited by various frequencies. The natural frequencies of some lightweight sandwich structures are in the frequency range sensitive to human hearing. When the excitation frequency is consistent with the natural frequency of the structure, the sound insulation and absorption ability of the sandwich structure for certain specific frequencies will be greatly reduced. For this reason, Chinese Patent 202311047250.6 designed a metamaterial sound-absorbing panel that couples a membrane shape and a Helmholtz resonance cavity. This sound insulation and absorption system realizes the resonance absorption of noise in a certain frequency band through two resonance cavities, improving the sound insulation and absorption amount at specific frequencies.

[0004] Due to the continuous increase in the speed of high-speed trains, a large pulsating wind pressure is generated on the sound insulation and absorption systems built on both sides of the high-speed rail line, thereby generating a large thrust and shear force on the sound insulation and absorption systems. However, the existing sound insulation and absorption systems have low strength and poor bending resistance, which easily lead to the bending deformation of the overall barrier, and thus pose potential safety hazards. For this reason, Chinese Patent 201010210965.5 designed a sound insulation and absorption barrier for high-speed railways with ventilation and pressure relief. This sound insulation and absorption system automatically adjusts the angle of the rotating sound-absorbing blades, significantly improving the bearing capacity and economy of the existing railway sound insulation barrier. However, the above-mentioned sound insulation and absorption systems have limited improvement in sound insulation and absorption performance and mechanical properties, and do not simultaneously improve the anti-deformation ability and resonance absorption ability. Summary of the Invention

[0005] The present invention proposes a micro-perforated truss sandwich sound insulation and absorption composite system, which comprehensively utilizes the truss structure, tile structure, and Helmholtz resonance structure, and can significantly improve the sound insulation and absorption ability and anti-deformation ability of traditional sound insulation and absorption systems.

[0006] A micro-perforated truss sandwich sound insulation and absorption composite system, characterized in that it includes multiple groups of tile-shaped scattering layers, truss sandwich structure units, and tile-shaped focusing layers arranged in an array;

[0007] The tile-shaped scattering layer includes a first closed circular arc frame, a first internal support truss, a micro-hole array, and a rigid pipe; the truss sandwich structure unit includes a cavity, evenly distributed micro-holes, a truss structure frame, an internal resonance mechanism, and a connecting plate; the tile-shaped focusing layer includes a second closed circular arc frame and a second internal support truss; the bottom of the tile-shaped scattering layer is closely arranged against the top of the truss sandwich structure unit, the bottom of the truss sandwich structure unit is closely arranged against the bottom of the tile-shaped focusing layer, and the truss sandwich structure units are closely connected through the side panels on both sides. Two truss sandwich structure units correspond to one tile-shaped scattering layer; the truss sandwich structure unit is arranged in the same direction as the tile-shaped scattering layer, and the tile-shaped focusing layer is arranged orthogonally to the tile-shaped scattering layer.

[0008] The tile-shaped scattering layer has a micro-hole array vertically penetrating from top to bottom. The arc surface of the first closed circular arc frame faces the sound source. The first internal support truss is composed of five vertical plates and four inclined plates. The micro-hole array is longitudinally arranged in four rows in the tile-shaped scattering layer, and the longitudinal distance between adjacent micro-holes in the micro-hole array is equal; the inner diameter of the rigid pipe is the same as the diameter of the micro-holes. The starting end of the rigid pipe coincides with the top micro-holes of the tile-shaped scattering layer, and the ending end of the rigid pipe coincides with the bottom micro-holes of the tile-shaped scattering layer. The rigid pipe avoids coinciding with the vertical plates of the first internal support truss.

[0009] The internal resonance mechanism in the truss sandwich structure unit and the truss structure frame form a cavity. The right triangle in the internal resonance mechanism has the same shape as the right triangle in the truss structure frame. The right triangle in the internal resonance mechanism is hollow, and the distance between the three sides of the right triangle in the internal resonance mechanism and the right triangle in the truss structure frame is equal. The evenly distributed micro-holes are at the top of the truss sandwich structure unit. The evenly distributed micro-holes in the truss sandwich structure unit are longitudinally arranged in two rows. The evenly distributed micro-holes at the top of the truss sandwich structure unit correspond one by one to the micro-holes in the micro-hole array at the bottom of the tile-shaped scattering layer. The cavity of the truss sandwich structure unit and the rigid pipe form a Helmholtz resonator. The connecting plate fixedly connects the internal resonance mechanism and the truss structure frame.

[0010] The arc surface of the second closed circular arc frame of the tile-shaped focusing layer faces away from the sound source. The second internal support truss is composed of five vertical plates and four inclined plates.

[0011] Furthermore, in the micro-perforated truss sandwich sound insulation and absorption composite system, the materials of the tile-shaped scattering layer, the truss sandwich structure unit, and the tile-shaped focusing layer are all metal or resin.

[0012] Further, in the truss-based micro-perforated sound insulation and absorption sandwich composite system, the tile-shaped scattering layer, the truss sandwich structure unit, and the tile-shaped focusing layer are produced by an integrated forming technology of model casting, welding, and 3D printing.

[0013] Further, the cross-section of the tile-shaped scattering layer and the tile-shaped focusing layer is symmetric about the center line.

[0014] The arc angles of the first closed circular arc frame and the second closed circular arc frame are the same as α. When the arc angle α is less than 30° or greater than 180°, it will cause local stress concentration, reducing the anti-deformation ability and the sound insulation and absorption ability of the sound insulation and absorption system. To provide good load distribution and improve the anti-deformation ability and the sound insulation and absorption ability of the sound insulation and absorption system, then α is greater than or equal to 30° and less than or equal to 180°.

[0015] The acute angle of the right triangle in the truss structure frame is β. When the acute angle β is greater than 0° and less than 30° or greater than 60° and less than 90°, it will cause a decrease in the force transfer efficiency and reduce the bearing capacity of the sound insulation and absorption system. To effectively disperse the load applied to the sound insulation and absorption system and improve the bearing capacity of the sound insulation and absorption system, then β is greater than or equal to 30° and less than or equal to 60°.

[0016] The beneficial effects of the micro-perforated truss sandwich sound insulation and absorption composite system provided by the present invention are as follows:

[0017] 1. The tile-shaped scattering layer and the truss sandwich structure unit jointly form a Helmholtz resonator and an internal resonance mechanism. By reasonably designing the relationship between the cavity volume of the Helmholtz resonator, the length of the rigid pipe, and the size of the internal resonance mechanism, the sound energy of the sound insulation and absorption system at the resonance frequency is effectively consumed, thereby improving the sound insulation and absorption amount of the sound insulation and absorption system at a specific frequency.

[0018] 2. The tile-shaped scattering layer and the tile-shaped focusing layer have the functions of scattering and focusing sound waves, enabling the sound waves to experience more reflections and refractions, thereby further improving the sound insulation and absorption ability of the sound insulation and absorption system.

[0019] 3. The tile-shaped scattering layer and the tile-shaped focusing layer are placed orthogonally and combined with the truss structure, enhancing the anti-deformation ability of the sound insulation and absorption system. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the design process for the truss-based micro-perforated sandwich sound insulation and absorption composite system;

[0021] Figure 2 It is a schematic diagram of the tile-shaped scattering layer in the present invention;

[0022] Figure 3 It is a schematic diagram of the truss sandwich structure unit in the present invention;

[0023] Figure 4 Schematic diagram of the tile-shaped focusing layer in the present invention;

[0024] Figure 5 Front view of the tile-shaped scattering layer in the present invention;

[0025] Figure 6 Front view of the truss sandwich structure unit in the present invention;

[0026] Figure 7 Front view of the tile-shaped focusing layer in the present invention.

[0027] In the figure: 1. Tile-shaped scattering layer; 2. Truss sandwich structure unit; 3. Tile-shaped focusing layer; 4. First closed circular arc frame; 5. First internal support truss; 6. Microporous array; 7. Rigid pipe; 8. Cavity; 9. Plain micropores; 10. Truss structure frame; 11. Internal resonance mechanism; 12. Connecting plate; 13. Second closed circular arc frame; 14. Second internal support truss. Detailed implementation manner

[0028] With reference to the accompanying drawings, the present invention is further described as follows:

[0029] As Figure 1 shown, a micro-perforated truss sandwich sound insulation and absorption composite system, characterized in that it includes a plurality of groups of tile-shaped scattering layers 1, truss sandwich structure units 2 and tile-shaped focusing layers 3 arranged in an array;

[0030] As Figure 1 shown, the tile-shaped scattering layer 1 includes a first closed circular arc frame 4, a first internal support truss 5, a microporous array 6, and a rigid pipe 7; the truss sandwich structure unit 2 includes a cavity 8, plain micropores 9, a truss structure frame 10, an internal resonance mechanism 11, and a connecting plate 12; the tile-shaped focusing layer 3 includes a second closed circular arc frame 13 and a second internal support truss 14; the bottom of the tile-shaped scattering layer 1 is closely attached to the top of the truss sandwich structure unit 2, the bottom of the truss sandwich structure unit 2 is closely attached to the bottom of the tile-shaped focusing layer 3, and the truss sandwich structure units 2 are closely connected by the side panels, and two truss sandwich structure units 2 correspond to one tile-shaped scattering layer 1; the truss sandwich structure unit 2 and the tile-shaped scattering layer 1 are arranged in the same direction, and the tile-shaped focusing layer 3 is arranged orthogonally to the tile-shaped scattering layer 1.

[0031] As Figure 2The shown tile-shaped scattering layer 1 has a microporous array 6 vertically penetrating from top to bottom. The arc surface of the first closed circular arc-shaped frame 4 faces the sound source. The first internal support truss 5 is composed of five vertical plates and four inclined plates. The microporous array 6 is longitudinally arranged in four rows in the tile-shaped scattering layer 1, and the longitudinal distance between adjacent micropores in the microporous array 6 is equal. The inner diameter of the rigid pipe 7 is the same as the micropore diameter. The starting end of the rigid pipe 7 coincides with the top micropores of the tile-shaped scattering layer 1, and the ending end of the rigid pipe 7 coincides with the bottom micropores of the tile-shaped scattering layer 1. The rigid pipe 7 avoids coinciding with the vertical plates of the first internal support truss 5.

[0032] As Figure 3 In the shown truss sandwich structure unit 2, the internal resonance mechanism 11 and the truss structure frame 10 form a cavity 8. The right-angled triangle in the internal resonance mechanism 11 has the same shape as the right-angled triangle in the truss structure frame 10. The right-angled triangle in the internal resonance mechanism 11 is hollow, and the distances between the three sides of the right-angled triangle in the internal resonance mechanism 11 and the right-angled triangle in the truss structure frame 10 are equal. The evenly distributed micropores 9 are at the top of the truss sandwich structure unit 2. The evenly distributed micropores 9 in the truss sandwich structure unit 2 are longitudinally arranged in two rows. The evenly distributed micropores 9 at the top of the truss sandwich structure unit 2 correspond one by one to the micropores of the microporous array 6 at the bottom of the tile-shaped scattering layer 1. The cavity 8 of the truss sandwich structure unit 2 and the rigid pipe 7 form a Helmholtz resonance structure. The connecting plate 12 fixedly connects the internal resonance mechanism 11 and the truss structure frame 10.

[0033] As Figure 4 The arc surface of the second closed circular arc-shaped frame 13 of the shown tile-shaped focusing layer 3 faces away from the sound source. The second internal support truss 14 is composed of five vertical plates and four inclined plates.

[0034] Furthermore, the parameters, production, and fixing methods of the tile-shaped scattering layer 1, the truss sandwich structure unit 2, and the tile-shaped focusing layer 3 are defined as follows:

[0035] In the described micro-perforated truss sandwich sound insulation and absorption composite system, the materials of the tile-shaped scattering layer 1, the truss sandwich structure unit 2, and the tile-shaped focusing layer 3 are all metal or resin.

[0036] In the described micro-perforated truss sandwich sound insulation and absorption composite system, the tile-shaped scattering layer 1, the truss sandwich structure unit 2, and the tile-shaped focusing layer 3 are all produced by using the integrated forming technology of model casting, welding, and 3D printing.

[0037] As Figure 5 And Figure 7 The cross-sections of the shown tile-shaped scattering layer 1 and the tile-shaped focusing layer 3 are symmetric about the center line.

[0038] As Figure 5 AndFigure 7 The arc angles of the first closed circular arc-shaped frame 4 and the second closed circular arc-shaped frame 13 shown are the same as α. When the arc angle α is less than 30° or greater than 180°, it will cause local stress concentration, reducing the anti-deformation ability and sound insulation and absorption ability of the sound insulation and absorption system. To provide good load distribution and enhance the anti-deformation ability and sound insulation and absorption ability of the sound insulation and absorption system, α is greater than or equal to 30° and less than or equal to 180°.

[0039] As Figure 6 shown, the acute angle of the right triangle in the truss structure frame 10 is β. When the acute angle β is greater than 0° and less than 30° or greater than 60° and less than 90°, it will cause a decrease in the force transmission efficiency and reduce the bearing capacity of the sound insulation and absorption system. To effectively disperse the load applied to the sound insulation and absorption system and enhance the bearing capacity of the sound insulation and absorption system, β is greater than or equal to 30° and less than or equal to 60°.

[0040] Furthermore, the calculation process of the selection rule of the parameters in the micro-perforated truss sandwich sound insulation and absorption composite system is as follows:

[0041] The rigid pipe 7 of the tile-shaped scattering layer 1 and the cavity of the truss sandwich structure unit 2 form a Helmholtz resonator. The resonance frequency calculation formula of the Helmholtz resonator is:

[0042]

[0043] where is the speed of sound, is the cross-sectional area of the opening of the rigid pipe 7, is the diameter of the rigid pipe 7, is the length of the rigid pipe 7, and V is the volume of the Helmholtz resonance cavity.

[0044] The resonance frequency calculation formula of the micro-perforated truss sandwich sound insulation and absorption composite system is:

[0045]

[0046] where is the compressive elastic modulus of the material of the truss sandwich structure unit 2, is the density of the tile-shaped scattering layer 1 and the tile-shaped focusing layer 3, is the thickness of the tile-shaped scattering layer 1 and the tile-shaped focusing layer 3, is the density of the material of the truss sandwich structure unit 2, and is the thickness of the truss sandwich structure unit 2.

[0047] Assume that under a certain working condition, a sound wave with a frequency of acts on a micro-perforated truss sandwich sound insulation and absorption composite system, and. Based on this, to improve the sound insulation and absorption amount of the micro-perforated truss sandwich sound insulation and absorption composite system at the sound wave frequency of, then. It can be seen that the resonance frequency of the micro-perforated truss sandwich sound insulation and absorption composite system is equal to the resonance frequency of the Helmholtz resonance cavity.

[0048] From Figure 5 the geometric relationship in, it can be obtained that:

[0049]

[0050] From Figure 6 the geometric relationships in

[0051]

[0052] From, the relationship between parameters in a micro-perforated truss sandwich sound insulation and absorption composite system can be deduced as:

[0053]

[0054] The specific working principle of a micro-perforated truss sandwich sound insulation and absorption composite system proposed by the present invention is:

[0055] The arc surface of the first closed circular arc frame in the tile-shaped scattering layer faces the sound source, and the arc surface of the first closed circular arc frame in the tile-shaped focusing layer faces the protected object. An incident sound wave will undergo multiple reflections and refractions when propagating from the working surface to the protected object. Each time of reflection and refraction, when encountering sound waves with the same frequency, phase, and direction, or with the same frequency, a phase difference of 180°, and opposite directions that happen to reach the same position, the two sound waves cancel out a part of each other, thereby reducing noise. In addition, through the design of micro-perforations, the sound insulation and absorption system can scatter low-frequency sound waves while absorbing high-frequency sound waves, thereby achieving a wide-band sound insulation and absorption effect.

[0056] The tile-shaped scattering layer, the truss sandwich structure unit, and the tile-shaped focusing layer all adopt truss structures, which not only form a high-strength structure but also reduce the overall weight. The upper and lower layers of the tile shape have the function of scattering and focusing sound waves, enabling the sound waves to undergo more reflections and refractions, thereby improving the sound insulation and absorption capacity of the sound insulation and absorption system. In addition, the orthogonally placed upper and lower layers of the tile shape further enhance the anti-deformation ability of the sound insulation and absorption system.

[0057] The sound insulation and absorption system is excited by sound waves of various frequencies. When the excitation frequency is consistent with the natural frequency of the sound insulation and absorption system, the sound insulation and absorption system will resonate, resulting in a significant reduction in the sound insulation amount and absorption capacity of the sound insulation and absorption system at certain specific frequencies. A truss-based micro-perforated sandwich composite system forms a Helmholtz resonator through the truss sandwich structure unit and the tile-shaped scattering layer, and combines with the internal resonance mechanism of the truss sandwich structure unit to effectively consume the sound energy of the sound insulation and absorption system at the resonance frequency, thereby improving the sound insulation and absorption ability of the sound insulation and absorption system at specific frequencies.

Claims

1. A micro-perforated truss sandwich sound insulation and absorption composite system, characterized in that: It includes multiple groups of tile-shaped scattering layers arranged in an array, truss sandwich structure units, and tile-shaped focusing layers; The tile-shaped scattering layer includes a first closed circular arc frame, a first internal support truss, a micropore array, and a rigid pipe; the truss sandwich structure unit includes a cavity, a flat micropore, a truss structure frame, an internal resonance mechanism, and a connecting plate; the tile-shaped focusing layer includes a second closed circular arc frame and a second internal support truss; the bottom of the tile-shaped scattering layer is closely arranged against the top of the truss sandwich structure unit, the bottom of the truss sandwich structure unit is closely arranged against the bottom of the tile-shaped focusing layer, and the truss sandwich structure units are closely connected through the side panels on both sides. Two groups of truss sandwich structure units correspond to one group of tile-shaped scattering layers; the truss sandwich structure units are arranged in the same direction as the tile-shaped scattering layer, and the tile-shaped focusing layer is arranged orthogonally to the tile-shaped scattering layer.

2. The micro-perforated truss sandwich sound insulation and absorption composite system according to claim 1, characterized in that: The tile-shaped scattering layer has a micropore array vertically penetrating from top to bottom. The arc surface of the first closed circular arc frame faces the sound source. The first internal support truss is composed of five vertical plates and four inclined plates. The micropore array is longitudinally arranged in four rows in the tile-shaped scattering layer, and the longitudinal distance between adjacent micropores in the micropore array is equal; the inner diameter of the rigid pipe is the same as the diameter of the micropores. The starting end of the rigid pipe coincides with the micropores at the top of the tile-shaped scattering layer, and the end of the rigid pipe coincides with the micropores at the bottom of the tile-shaped scattering layer. The rigid pipe avoids coinciding with the vertical plates of the first internal support truss.

3. The micro-perforated truss sandwich sound insulation and absorption composite system according to claim 1, characterized in that: The internal resonance mechanism in the truss sandwich structure unit and the truss structure frame form a cavity. The right triangle in the internal resonance mechanism has the same shape as the right triangle in the truss structure frame. The right triangle in the internal resonance mechanism is hollow, and the distance between the three sides of the right triangle in the internal resonance mechanism and the right triangle in the truss structure frame is equal. The flat micropores are at the top of the truss sandwich structure unit. The flat micropores are longitudinally arranged in two rows in the truss sandwich structure unit. The flat micropores at the top of the truss sandwich structure unit correspond one by one to the micropores in the micropore array at the bottom of the tile-shaped scattering layer. The cavity of the truss sandwich structure unit and the rigid pipe form a Helmholtz resonator. The connecting plate fixedly connects the internal resonance mechanism and the truss structure frame.

4. A micro-perforated truss sandwich sound insulation and absorption composite system according to claim 1, characterized in that: The arc surface of the second closed circular arc frame of the tile-shaped focusing layer faces away from the sound source. The second internal support truss is composed of five vertical plates and four inclined plates.

5. The micro-perforated truss sandwich sound insulation and absorption composite system according to claim 1, wherein: The materials of the tile-shaped scattering layer, the truss sandwich structure unit, and the tile-shaped focusing layer are all metal or resin.

6. The micro-perforated truss sandwich sound insulation and absorption composite system according to claim 1, characterized in that: The tile-shaped scattering layer, the truss sandwich structure unit, and the tile-shaped focusing layer are all produced by using model casting, welding, or 3D printing integrated forming technology.

7. A micro-perforated truss sandwich sound insulation and absorption composite system according to claim 4, characterized in that: The cross-sections of the tile-shaped scattering layer and the tile-shaped focusing layer are symmetric about the center line.

8. The micro-perforated truss sandwich sound insulation and absorption composite system according to claim 1, characterized in that: The arc angles of the first closed circular arc frame and the second closed circular arc frame are the same as α. To provide good load distribution and improve the anti-deformation ability and sound insulation and absorption ability of the sound insulation and absorption system, then α is greater than or equal to 30° and less than or equal to 180°.

9. The micro-perforated truss sandwich sound insulation and absorption composite system according to claim 3, characterized in that: The acute angle of the right triangle in the truss structure framework is β. To effectively disperse the load applied to the sound insulation and absorption system and improve the bearing capacity of the sound insulation and absorption system, β is greater than or equal to 30° and less than or equal to 60°.

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