Equal-height bending acoustic metasurface plate structure

Abstract

The utility model discloses an equal-height bending acoustic metasurface plate structure, a metasurface plate is formed by splicing a plurality of sound absorption units in sequence, each sound absorption unit comprises a sound absorption cavity formed by a front cover plate, a rear cover plate and a frame, and a bending spiral plate is arranged in the sound absorption cavity. The bent spiral plate is bent in a square spiral line shape from the middle point of the sound absorption cavity to the periphery, so that a spiral bent channel is formed in the bent spiral plate, a through hole is formed in the middle of the front cover plate, and an embedded hole in butt joint with the through hole is formed in the sound absorption cavity. Different sizes of the sound absorption units in the metasurface plate are designed according to the frequency distribution range of noise, and different lengths of the bent spiral plates are designed according to different frequency bands of the noise in the sound absorption units, so that different frequencies corresponding to sound absorption peak values are adjusted through the sound absorption units with different sizes; and the frequency range corresponding to the sound absorption peak value is further expanded by arranging a plurality of bent spiral plates with different lengths.

Description

TECHNICAL FIELD

[0001] The utility model relates to low frequency broadband noise control field, and a kind of equal-height bending acoustic metasurface panel structure specifically. BACKGROUND

[0002] Range hood can produce great noise in working process, and because the installation space of kitchen is limited, so the size of noise reduction structure should be minimized. It is very important for range hood to study the noise reduction technology of small size controlling large wavelength, especially the noise reduction of range hood low frequency below 1000Hz.

[0003] The prior art discloses a perfect sound absorption bending metasurface panel, a plurality of sound absorption units of equal size are arranged on the metasurface panel, and the bending spiral plates in each sound absorption unit are equal in length. The structure causes that the frequency range corresponding to the sound absorption peak of the metasurface panel has limitations, and cannot perfectly absorb noise. UTILITY MODEL CONTENTS

[0004] In view of the above shortcomings, the utility model provides an equal-height bending acoustic metasurface panel structure which can perfectly absorb noise, and the specific scheme is as follows:

[0005] An equal-height bending acoustic metasurface panel structure, the metasurface panel is composed of a plurality of sound absorption units connected in sequence, the sound absorption unit comprises a sound absorption cavity composed of a front cover plate, a rear cover plate and a frame, a bending spiral plate is arranged in the sound absorption cavity, the bending spiral plate is bent outward in a square spiral line shape from the midpoint of the sound absorption cavity, so that a spiral bending channel is formed in the inside, a through hole is arranged in the middle of the front cover plate, an embedded hole is arranged in the sound absorption cavity and is opposite to the through hole, the metasurface panel comprises a first sound absorption unit corresponding to the noise frequency distribution range of 326-550Hz, a second sound absorption unit corresponding to the noise frequency distribution range of 384-570Hz, a third sound absorption unit corresponding to the noise frequency distribution range of 420-600Hz and a fourth sound absorption unit corresponding to the noise frequency distribution range of 450-680Hz, and the areas of the first sound absorption unit, the second sound absorption unit, the third sound absorption unit and the fourth sound absorption unit decrease in sequence.

[0006] And the sound absorption coefficient frequency band of the metasurface panel is 372-735Hz above 0.5, and the length of the bending channel in the plurality of sound absorption units is 179-1750mm.

[0007] Further, the length of the embedded hole is less than the height of the bending channel.

[0008] Further, the metasurface panel is a square, and the sum of the areas of the plurality of sound absorption units is equal to the area of the metasurface panel.

[0009] Further, the metasurface panel is a square with a side length of 350 mm, and the plurality of sound absorption units are all squares, wherein,

[0010] The first sound absorption unit has a side length of 200 mm, and the number thereof in the metasurface panel is 1;

[0011] The second sound absorption unit has a side length of 150 mm, and the number thereof in the metasurface panel is 2;

[0012] The third sound absorption unit has a side length of 100 mm, and the number thereof in the metasurface panel is 2;

[0013] The fourth sound absorption unit has a side length of 50 mm, and the number thereof in the metasurface panel is 7.

[0014] Further, the thickness of the metasurface panel is the sum of the thickness of the front cover plate, the thickness of the rear cover plate and the height of the bending channel.

[0015] Further, the hole radius r of the embedded hole in the plurality of sound absorption units is n arbitrarily selected between 1 and 5 mm, and the length l n is arbitrarily selected between 1 and 10 mm.

[0016] Further, the width w of the bending channel in the plurality of sound absorption units is arbitrarily selected between 9 and 70 mm, the length L is arbitrarily selected between 179 and 245 mm, and the height h is all 10 mm.

[0017] Further, the material of the metasurface panel is resin.

[0018] Further, the metasurface panel is integrally formed by 3D printing.

[0019] Compared with the prior art, the advantages of the present application are as follows:

[0020] 1. In the present application, the sound absorption peak corresponding to different frequencies is adjusted by a plurality of sound absorption units of different sizes, and the frequency range corresponding to the sound absorption peak is further expanded by setting a plurality of bending spiral plates of different lengths.

[0021] 2. In the present application, the sum of the areas of the plurality of sound absorption units is equal to the area of the metasurface panel, so that the sound absorption units in the metasurface panel are arranged compactly, and the sound absorption effect is further improved.

[0022] 5. In the present application, the length and radius of the embedded hole in the metasurface unit are controlled to control the equivalent acoustic impedance of the plurality of sound absorption units, thereby achieving beneficial and flexible control of the sound absorption coefficient peak and the corresponding frequency of the plurality of sound absorption units, increasing the geometric dimension of the sound absorption performance control of the plurality of sound absorption units, and widening the adjustable range of the sound absorption peak and the frequency.

[0023] 4. The resin is integrally formed by the 3D printer, which has the advantage of stabilizing the structure of multiple sound absorption units. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a perspective view of a sound absorption unit;

[0025] Figure 2 is Figure 1 is a front view

[0026] Figure 3 is a structure diagram of a front cover plate;

[0027] Figure 4 is a structure diagram of an embedded hole;

[0028] Figure 5 , Figure 6 are structure diagrams of bending channels;

[0029] Figure 7 is a structure diagram of a frame;

[0030] Figure 8 is a structure diagram of a metasurface plate;

[0031] Figure 9 is an experimental configuration of a metasurface plate;

[0032] Figure 10 is the A-weighted noise reduction amount at measuring point A for different schemes A;

[0033] Figure 11 is the A-weighted noise reduction amount at measuring point B for different schemes A;

[0034] Figure 12 is the A-weighted noise reduction amount at measuring point C for different schemes A;

[0035] Figure 13 is the A-weighted noise reduction amount at measuring point D for different schemes A;

[0036] REFERENCE NUMERALS:

[0037] 1. Front cover plate; 2. Through hole; 3. Rear cover plate; 4. Embedded hole; 5. Metasurface plate; 6. Bending channel; 7. Frame. DETAILED DESCRIPTION

[0038] The technical scheme of the utility model will be described in detail below in combination with the accompanying drawings. Figures 1 to 8 The technical scheme of the utility model will be described in detail below in combination with the accompanying drawings.

[0039] Example 1

[0040] As Figures 1 to 8As shown, an equal-height bending acoustic metasurface panel structure, the material of the metasurface panel 5 is resin, the metasurface panel 5 is composed of a plurality of sound absorption units in turn spliced, the sound absorption unit includes a sound absorption cavity composed of a front cover plate 1, a rear cover plate 3 and a frame 7, a bending spiral plate is arranged in the sound absorption cavity, the bending spiral plate is bent in a square spiral line shape from the midpoint of the sound absorption cavity to the outer periphery, so that a spiral bending channel 6 is formed in the inside, a through hole 2 is arranged in the middle of the front cover plate 1, an embedded hole 4 is arranged in the sound absorption cavity and is opposite to the through hole 2, the length of the embedded hole 4 is less than the height of the bending channel 6, the metasurface panel 5 includes a first sound absorption unit corresponding to a noise frequency distribution range of 326-550Hz, a second sound absorption unit corresponding to a noise frequency distribution range of 384-570Hz, a third sound absorption unit corresponding to a noise frequency distribution range of 420-600Hz, and a fourth sound absorption unit corresponding to a noise frequency distribution range of 450-680Hz, and the areas of the first sound absorption unit, the second sound absorption unit, the third sound absorption unit and the fourth sound absorption unit decrease in turn; the control frequency distribution range exists overlap, and the units are selected according to the uniform distribution of frequency step. The plurality of sound absorption units are square,

[0041] The length of the side of the first sound absorption unit is 200mm, and the number of the first sound absorption unit in the metasurface panel 5 is 1;

[0042] The length of the side of the second sound absorption unit is 150mm, and the number of the second sound absorption unit in the metasurface panel 5 is 2;

[0043] The length of the side of the third sound absorption unit is 100mm, and the number of the third sound absorption unit in the metasurface panel 5 is 2;

[0044] The length of the side of the fourth sound absorption unit is 50mm, and the number of the fourth sound absorption unit in the metasurface panel 5 is 7, and the total number of the sound absorption units is 12.

[0045] And the sound absorption coefficient frequency band of the metasurface panel 5 is 372-735Hz above 0.5, and the length of the bending channel in the plurality of sound absorption units is 179-1750mm. The metasurface panel 5 is integrally formed by 3D printing.

[0046] Embodiment 2

[0047] As shown in the figure, Figures 4 to 8 The metasurface panel and the plurality of sound absorption units are square, wherein a is the length of the side of the frame, w is the width of the bending channel, L is the equivalent length of the bending channel, r n is the radius of the embedded hole, l n is the length of the embedded hole, and h is the height of the bending channel.

[0048] As shown in the figure, Figure 7As shown, the spatial on the xoy plane of the metasurface panel, while being able to regulate the frequency range of high-efficiency sound absorption in a wide frequency band, a 35cm-long edge and 12mm-thick ultrathin broadband composite metasurface panel composed of 12 sound absorption units, such as Figure 3 As shown. The composite metasurface panel unit contains 7 units with an edge length of 50mm, 2 units with an edge length of 100mm, 2 units with an edge length of 150mm, and 1 unit with an edge length of 200mm, a total of 12 sound absorption units, which are named units 1-12 according to the change of edge length. The parameters of units 1 to 12 are shown below:

[0049] The fourth sound absorption unit a, a1=50mm, r n1 =1mm, l n1 =7mm, w1=9mm, L1=179mm, h1=10mm, the sound absorption peak corresponds to the frequency: 488Hz;

[0050] The fourth sound absorption unit b, a2=50mm, r n2 =1mm, l n2 =10mm, w2=10mm, L2=245mm, h2=10mm, the sound absorption peak corresponds to the frequency: 463Hz.

[0051] The fourth sound absorption unit c, a3=50mm, r n3 =2mm, l n3 =6mm, w3=10mm, L3=245mm, h3=10mm, the sound absorption peak corresponds to the frequency: 546Hz.

[0052] The fourth sound absorption unit d, a4=50mm, r n4 =2mm, l n4 =4mm, w4=10mm, L4=245mm, h4=10mm, the sound absorption peak corresponds to the frequency: 565Hz.

[0053] The fourth sound absorption unit e, a5=50mm, r n5 =2mm, l n5 =1mm, w5=10mm, L5=245mm, h5=10mm, the sound absorption peak corresponds to the frequency: 603Hz.

[0054] The fourth sound absorption unit f, a6=50mm, r n6 =2mm, l n6 =1mm, w6=10mm, L6=245mm, h6=10mm, the sound absorption peak corresponds to the frequency: 514Hz.

[0055] The fourth sound absorption unit g, a7=50mm, r n7 =5mm, l n7= 1 mm, w7 = 11 mm, L7 = 245 mm, h7 = 10 mm, sound absorption peak corresponding frequency: 672 Hz.

[0056] Third sound absorption unit a, a8 = 100 mm, r n8 = 1 mm, l n8 = 10 mm, w8 = 12 mm, L8 = 658 mm, h8 = 10 mm, sound absorption peak corresponding frequency: 425 Hz.

[0057] Third sound absorption unit b, a9 = 100 mm, r n9 = 2 mm, l n9 = 7 mm, w9 = 25 mm, L9 = 723 mm, h9 = 10 mm, sound absorption peak corresponding frequency: 447 Hz.

[0058] Second sound absorption unit a, a 10 = 150 mm, r n10 = 1 mm, l n10 = 10 mm, w 10 = 50 mm, L 10 = 640 mm, h 10 = 10 mm, sound absorption peak corresponding frequency: 424 Hz.

[0059] Second sound absorption unit b, a 11 = 150 mm, r n11 = 2 mm, l n11 = 1 mm, w 11 = 12 mm, L 11 = 1750 mm, h 11 = 10 mm, sound absorption peak corresponding frequency: 436 Hz.

[0060] First sound absorption unit, a 12 = 200 mm, r n12 = 1 mm, l n12 = 10 mm, w 12 = 70 mm, L 12 = 870 mm, h 12 = 10 mm, sound absorption peak corresponding frequency: 421 Hz.

[0061] The structure adopts 3D printing technology to prepare a square structure metasurface panel 5 with a side length of 350 mm and a thickness of 12 mm (bending channel height 10 mm + front cover plate 1 thickness 1 mm + rear cover plate 3 thickness 1 mm). The base material used for 3D printing is R4600 resin, with a density of 1.13 kg / m3 and a Poisson's ratio of 0.42.

[0062] The high-efficiency sound absorption mechanism of the above structure is from the local resonance of sound energy in the bending channel and the space outside the channel and the coherent cancellation of sound waves at the embedded hole port position.

[0063] Generally, the frequency band with a sound absorption coefficient of 0.8 or above is considered as a high-efficiency sound absorption frequency band, and for a noise reduction structure, especially a noise reduction structure combined with a rigid sound insulation structure, a structure with a sound absorption coefficient of 0.5 or above is considered as a better noise reduction acoustic metasurface panel which can obviously reduce the reverberation formed by the rigid wall. The sound absorption frequency band with a sound absorption coefficient of 0.8 or above of the optimized unit of the equal-height acoustic metasurface panel is 397Hz-706Hz, and the high-efficiency sound absorption frequency band has a bandwidth of 309Hz; the noise reduction frequency band with a sound absorption coefficient of 0.5 or above is 372Hz-735Hz, and the noise reduction frequency band has a bandwidth of 363Hz, so the ultrathin sound absorption metasurface panel composed of the equal-height metasurface panel units optimized at different scales has good noise reduction effect in the medium and low frequency range of 372Hz-735Hz with a bandwidth of 363Hz. It can be seen that the equal-height bending acoustic metasurface panel has good sound absorption performance in the medium and low frequency noise band, and the thickness is significantly reduced.

[0064] Example 3

[0065] The experimental scheme of the metasurface panel is as follows:

[0066] The experiment is tested according to the standard GB / T17713-2011, the test environment is a semi-anechoic chamber, the test method is a global envelope method, and the test point position is arranged as shown in Figure 9 .

[0067] According to the standard GB / T17713-2011, the noise radiated by the range hood is characterized by the A-weighted 1 / 3 octave average sound pressure level at four measurement points, that is, the average value of the 1 / 3 octave A-weighted sound level at four positions is selected as the range hood noise level. The position of measurement point A in the experiment is the back of the range hood, that is, the main radiation noise surface of the internal motor, the position of measurement point B is the right side of the range hood, the position of measurement point C is the front of the range hood, that is, the back of the main radiation direction of the internal motor, and the position of measurement point D is the left side of the range hood. The test system includes a B&K3050 acquisition front end, four B&K4957 type 1 / 4 inch sensors, a Pulse acquisition post-processing software, and a PC.

[0068] The wedge-shaped black polyurethane porous sound-absorbing cotton with a length-width size of 30mm*30mm is installed in the range hood, the wedge-shaped thickness is 24.5mm and 38.5mm respectively, as a pure porous comparison structure one, and a resin plate with a thickness of 1mm front and back cover plate and 10mm cavity composite is used as a cavity comparison structure two. According to the size distribution of the range hood, the actual main noise reduction space size is 417mm*467mm, the secondary noise reduction space size is 417mm*416mm, and the maximum thickness that can be accommodated in the thickness direction is 38.5mm, and the maximum size of the equal-height bending acoustic metasurface plate designed in the study is 350mm*350mm*20mm, which fully meets the installation requirements of the noise reduction space.

[0069] From Figure 10 It can be seen that at the test point A, the equal-height metasurface plate has better noise reduction effect than the pure porous material and the cavity comparison structure in the 400Hz and 500Hz frequency bands. From Figure 11 It can be seen that the equal-height metasurface plate has better noise reduction effect than the porous and cavity comparison groups in the 500Hz and 630Hz frequency bands at the same test point B. Figure 12 The test point C in Figure 13 The test point D in Figure 10 , Figure 11 , Figure 12 , Figure 13 It can be found that the equal-height acoustic metasurface plate can significantly improve the noise reduction effect in the 400Hz, 500Hz and 630Hz frequency bands. Since the above frequency points correspond to the 1 / 3 octave range, it can be confirmed that the equal-height metasurface plate has significantly improved noise reduction effect in the 400Hz-630Hz frequency band, and the average noise reduction of the equal-height acoustic metasurface plate in the 400Hz-630Hz frequency band is more than 1.4dB(A), which indicates the noise reduction advantage of the designed equal-height metasurface plate in the working frequency band.

[0070] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for part of the technical features; and these modifications or substitutions will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An equal-height bending acoustic metasurface panel structure, the metasurface panel (5) is composed of a plurality of sound absorption units spliced in turn, the sound absorption unit comprises a sound absorption cavity composed of a front cover plate (1), a rear cover plate (3) and a frame (7), a bending spiral plate is arranged in the sound absorption cavity, the bending spiral plate is bent in a square spiral line shape from the midpoint of the sound absorption cavity to the outer periphery, so that a spiral bending channel (6) is formed in the inside, a through hole (2) is arranged in the middle of the front cover plate (1), an embedded hole (4) is arranged in the sound absorption cavity and is opposite to the through hole (2), characterized in that, The first sound absorption unit is arranged corresponding to the noise frequency distribution range of 326-550 Hz, the second sound absorption unit is arranged corresponding to the noise frequency distribution range of 384-570 Hz, the third sound absorption unit is arranged corresponding to the noise frequency distribution range of 420-600 Hz, and the fourth sound absorption unit is arranged corresponding to the noise frequency distribution range of 450-680 Hz, and the areas of the first, second, third and fourth sound absorption units decrease in turn; The length of the bending channel (6) in the plurality of sound absorption units is arranged in the sound absorption coefficient frequency range of 372-735 Hz and is between 179-1750 mm.

2. The equal-height meandering acoustic metasurface panel structure of claim 1, wherein, The length of the embedded hole (4) is less than the height of the bending channel (6).

3. The equal-height meandering acoustic metasurface panel structure of claim 2, wherein, The super surface panel (5) is a square, and the sum of the areas of the plurality of sound absorption units is equal to the area of the super surface panel (5).

4. The equal-height meandering acoustic metasurface panel structure of claim 3, wherein, The super surface panel (5) is a square with a side length of 350 mm, and the plurality of sound absorption units are all squares, wherein, The first sound absorption unit has a side length of 200 mm and a quantity of 1 in the super surface panel (5); The second sound absorption unit has a side length of 150 mm and a quantity of 2 in the super surface panel (5); The third sound absorption unit has a side length of 100 mm and a quantity of 2 in the super surface panel (5); The fourth sound absorption unit has a side length of 50 mm and a quantity of 7 in the super surface panel (5).

5. The equal-height meandering acoustic metasurface panel structure of claim 1, wherein, The thickness of the super surface panel (5) is the sum of the thickness of the front cover plate (1), the thickness of the rear cover plate (3) and the height of the bending channel (6).

6. The equal-height meandering acoustic metasurface panel structure of claim 2, wherein, Hole radius r of the inner embedded hole (4) in the plurality of sound absorption units n Length l is arbitrarily selected between 1 and 5 mm n Length l is arbitrarily selected between 1 and 10 mm.

7. The equal-height meandering acoustic metasurface panel structure of claim 1, wherein, The width w of the bending channel (6) in the plurality of sound absorption units is randomly selected between 9-70 mm, and the height h is 10 mm.

8. The equal-height meandering acoustic metasurface panel structure of claim 5, wherein, The material of the super surface panel (5) is resin.

9. The equal-height meandering acoustic metasurface panel structure of claim 8, wherein, The super surface panel (5) is integrally formed by 3D printing.

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