Assembly type acoustic device for sound absorption and insulation
By introducing periodic arrangements of phononic crystals and cavities into the acoustic device, the problem of insufficient low-frequency noise attenuation in traditional acoustic materials is solved, achieving efficient low-frequency noise absorption and insulation effects, and making it suitable for vibration-free environments of precision equipment.
Patent Information
- Application Number
- CN202422929188.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Traditional acoustic materials are less effective at absorbing low-to-mid-frequency noise, especially below 500Hz.
An assembled acoustic device employs an EVA layer with phonon crystals and a PU foam layer with cavities. The phonon crystals are seamlessly embedded in the pores of the PU foam layer, and the two are arranged periodically, combining the properties of EVA and PU materials to enhance low-frequency noise absorption.
It significantly improves the sound insulation performance of low-frequency noise, meets the sound absorption and insulation requirements of different frequency bands, and the device is lightweight, making it suitable for vibration-free working environments of high-precision machining systems and special precision instruments.
Smart Images
Figure CN223582683U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a kind of assembled acoustic devices, specifically to a kind of assembled composite structure acoustic device for sound absorption and insulation. BACKGROUND
[0002] Traditional acoustic materials are good in high-frequency noise absorption, but weak in mid-low frequency noise attenuation, especially for noise below 500Hz. Therefore, effective acoustic materials or structures or devices are needed to control the propagation of low-frequency noise. SUMMARY
[0003] To overcome the above technical problems, the utility model provides an assembled acoustic device for sound absorption and insulation.
[0004] The utility model discloses the inventive concept is that the sound insulation material is mainly related to the vibration suppression effect of the local resonance unit periodically attached to the base structure. In the field of structural vibration control, if a metamaterial with elastic wave bandgap characteristics is selected, the vibration response of the base structure surface at the resonance frequency of the local resonance unit may be significantly suppressed due to the vibration suppression effect of the local resonance unit attached to the base structure, and sound waves cannot be effectively radiated, thereby forming a sound insulation amount far exceeding the law of mass. Phononic crystals have a specific frequency band, and there is a sound wave and elastic wave propagation bandgap, i.e., a bandgap, in the frequency band. In the frequency range outside the bandgap, the propagation of sound waves and elastic waves in the phononic crystal will not be lost. This characteristic makes the phononic crystal an effective low-frequency vibration and noise reduction method. The concept forms an acoustic device with good sound insulation function by assembling the phononic crystal with other sound insulation materials.
[0005] The utility model provides a kind of assembled acoustic device for sound absorption and insulation, including EVA layer with phononic crystal and PU foaming layer with cavity, PU foaming layer with cavity is opened with the hole corresponding with the size of phononic crystal in EVA layer with phononic crystal, and phononic crystal is seamlessly embedded in the hole of PU foaming layer.
[0006] Further, in the assembled acoustic device for sound absorption and insulation provided by the utility model, the phononic crystals and the cavities are periodically arranged.
[0007] Further, in the assembled acoustic device for sound absorption and insulation provided by the utility model, the distance between adjacent phononic crystals in the EVA layer with phononic crystals is 5-15 mm.
[0008] Further, in the assembled acoustic device for sound absorption and insulation provided by the utility model, the distance between adjacent cavities in the PU foaming layer with cavities is 5-15 mm.
[0009] Further, in the assembly type acoustic device for absorbing and isolating sound provided by the utility model, the length, width and height of the phononic crystal in the EVA layer with the phononic crystal are (10-15 mm), (10-15 mm) and (5-8 mm) respectively.
[0010] Further, in the assembly type acoustic device for absorbing and isolating sound provided by the utility model, the length, width and height of the cavity in the PU foaming layer with the cavity are (10-15 mm), (10-15 mm) and (5-8 mm) respectively.
[0011] Further, in the assembly type acoustic device for absorbing and isolating sound provided by the utility model, the number of the phononic crystals is 4*4.
[0012] Further, in the assembly type acoustic device for absorbing and isolating sound provided by the utility model, the EVA layer with the phononic crystal adopts EVA with an elastic modulus of 2*10 8 Pa, a density of 1500 Kg / m 3 .
[0013] Further, in the assembly type acoustic device for absorbing and isolating sound provided by the utility model, the PU foaming layer with the cavity adopts PU with an elastic modulus of 8*10 4 Pa, a density of 60 Kg / m 3 and a damping loss factor of 0.15.
[0014] The assembly type acoustic device for absorbing and isolating sound has the following advantages: (1) compared with the traditional structure, the overall sound insulation performance is improved; (2) especially, the sound insulation at low frequency is obviously improved; (3) the acoustic performance can be adjusted by adjusting the thickness and the structure distribution, so that the requirements of sound absorption and isolation of different frequency bands are met; (4) light weight is realized. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 The utility model discloses assembly type acoustic device finished product structure schematic diagram;
[0016] Figure 2 The utility model discloses assembly type acoustic device finished product structure schematic diagram;
[0017] Figure 3 The utility model discloses assembly type acoustic device finished product structure schematic diagram;
[0018] Figure 4 The utility model discloses assembly type acoustic device finished product structure schematic diagram;
[0019] Figure 5The schematic view of the composite structure of the PU foaming layer with cavity and the EVA layer without phononic crystal
[0020] Figure 6 The comparison chart of the insertion loss of the assembled acoustic device and the traditional structure
[0021] Figure 7 The relationship chart of the phononic crystal height (thickness) and the insertion loss in the assembled acoustic device
[0022] Figure 8 The relationship chart of the phononic crystal quantity and the insertion loss in the assembled acoustic device
[0023] In the figure: 1-EVA layer with phononic crystal; 2-PU foaming layer with cavity; 3-cavity; 4-EVA thin layer; 5-phononic crystal; 6-hole corresponding to the phononic crystal in the PU foaming layer; 7-PU foaming layer without cavity; 8-PU foaming layer without hole with cavity; a-1 phononic crystal; b-2 phononic crystals; 3-3 phononic crystals; 4-4 phononic crystals DETAILED DESCRIPTION
[0024] The utility model is further described in connection with the drawings.
[0025] As Figure 1 , Figure 2 , Figure 3 indicated, the utility model provides a kind of for absorbing sound insulation assembled acoustic device, including EVA layer 1 with phononic crystal and PU foaming layer 2 with cavity.PU foaming layer 2 with cavity is opened with the hole 6 corresponding to the size of phononic crystal 5 in EVA layer 1 with phononic crystal, and phononic crystal 5 seamlessly embeds the hole 6 of PU foaming layer 2.
[0026] As Figure 2 indicated, EVA layer 1 with phononic crystal can be divided into EVA thin layer 4 and phononic crystal 5.The thickness of EVA thin layer 4 is set according to application scenario, and is usually set to 1mm.The length-width-height setting of phononic crystal and the interval of adjacent phononic crystal have greater influence on the sound absorption and insulation performance of assembled acoustic device.Phononic crystal 5 is periodically arranged.The utility model is simulated by simulation, and the length of phononic crystal is preferably 10-15mm, the width is 10-15mm, and the height is 5-8mm.The interval of adjacent phononic crystal is 5-15mm.
[0027] As Figure 3As shown, holes 6 corresponding to the phononic crystal size are opened in the PU foaming layer 2, the phononic crystal 5 is seamlessly embedded in the holes 6 of the PU foaming layer, and the PU foaming layer is provided with cavities 3. The cavities 3 are periodically arranged. The length, width and height of the cavities 3, the spacing of adjacent cavities and the periodic arrangement rule are consistent with the corresponding phononic crystal. Through simulation and optimization, the length of the cavity 3 is 10-15mm, the width is 10-15mm, and the height is 5-8mm.
[0028] The EVA layer can adopt commercially available EVA materials, preferably the EVA elastic modulus is 2*10 8 Pa, and the density is 1500Kg / m 3 . The PU foaming layer can adopt commercially available PU materials, preferably the elastic modulus of PU is 8*10 4 Pa, the density is 60Kg / m 3 , and the damping loss factor is 0.15. The acoustic performance of the assembled acoustic device can be improved by adjusting the number, size design and spacing of adjacent phononic crystals of the EVA phononic crystal, so as to realize the sound absorption and insulation requirements of specific frequency bands.
[0029] The acoustic device assembled with the phononic crystal can on the one hand provide a vibration-free machining environment within the adjustable frequency band for high-precision machining systems, ensuring higher machining precision requirements; on the other hand, it can provide a vibration-free working environment for special precision instruments or equipment, improve the working precision and reliability, and prolong the service life of the equipment.
[0030] A three-dimensional model of the assembled acoustic device is established by simulation software and physical simulation calculation is carried out to calculate the sound insulation amount of the device. (1) Establishment of three-dimensional model of assembled acoustic device. The boundary is set at the first layer, the purpose is to absorb the sound waves reflected to the incident sound field on the upper surface, so as to prevent them from being reflected into the acoustic covering layer; the second layer is the incident sound field air layer B, and the background pressure field is set in the incident sound field to simulate the incident sound wave. (2) Simulation. The air domain is set at both ends of the model to simulate the incident sound field and the outgoing sound field, and the plane wave radiation boundary condition is used at the incident end to simulate the incident wave. (3) Calculation result. The simulation parameters are selected as follows: the length and width of the EVA layer are both 155mm, and the height is 1mm; the length and width of a single phononic crystal are both 15mm, and the height is 8mm; the length and width of the PU foaming layer are both 155mm, and the height is 20mm; the length and width of a single cavity are both 15mm, and the height is 8mm.
[0031] Example 1
[0032] As Figure 2As shown, the EVA thin layer 4 is set to have a length of 155 mm, a width of 155 mm, and a height of 1 mm; the single phononic crystal 5 has a length and a width of 15 mm and a height of 8 mm; the number of phononic crystals is 4*4, and the spacing between adjacent single phononic crystals is 15 mm; the EVA thin layer and the phononic crystal are 3D printed into an EVA layer 1 with phononic crystals. As shown in FIG. 2, the EVA layer 1 with phononic crystals is set to have a length of 155 mm, a width of 155 mm, and a height of 1 mm; the single phononic crystal 5 has a length and a width of 15 mm and a height of 8 mm; the number of phononic crystals is 4*4, and the spacing between adjacent single phononic crystals is 15 mm. Figure 3 As shown, the PU foaming layer has a length and a width of 155 mm and a height of 45 mm; the single cavity has a length and a width of 15 mm and a height of 8 mm; the number of cavities is 4*4, and the spacing between adjacent single cavities is 15 mm. The EVA layer has an EVA elastic modulus of 2*10 8 Pa, a density of 1500 Kg / m 3 . The PU foaming layer has an elastic modulus of 8*10 4 Pa, a density of 60 Kg / m 3 , and a damping loss factor of 0.15.
[0033] Example 2
[0034] The height or thickness of the phononic crystal is 10 mm, and the height of the corresponding cavity is also 10 mm. Other parameters such as the length, width, and height of the EVA thin layer 4, the length and width of the single phononic crystal 5, the number of phononic crystals, the spacing between adjacent phononic crystals, the length, width, and height of the PU foaming layer, the length and width of the single cavity, the number of cavities, and the spacing between adjacent cavities are the same as in Example 1.
[0035] Example 3
[0036] The spacing between the phononic crystals is 5 mm, and the spacing between adjacent single cavities is also 5 mm. Other parameters are the same as in Example 1 or Example 2.
[0037] Test results: The thicknesses of the phononic crystals 5 in Examples 1, 2, and 3 are selected to be 15 mm, 10 mm, and 5 mm, respectively, for a comparative test of the insertion loss of the phononic crystal acoustic device with different heights (thicknesses). The test results are shown in FIG. 3. Figure 7 It can be clearly seen that the EVA layer + PU layer with cavities assembled into the acoustic device has the highest sound insulation effect.
[0038] Example 4
[0039] Other parameters are the same as in Example 1, except that the number of phononic crystals is 1.
[0040] Example 5
[0041] Other parameters are the same as in Example 1, except that the number of phononic crystals is 2.
[0042] Example 6
[0043] Other parameters are the same as example 1, except that the number of phononic crystals is 3.
[0044] Example 7
[0045] Other parameters are the same as example 1, except that the number of phononic crystals is 4.
[0046] Test results: the number of single phononic crystal 5 in examples 4-7 is respectively selected as 1, 2, 3 and 4 for different number of phononic crystal acoustic device insertion loss comparison test, and the test results are shown in Figure 8 . Among them, a is 1 phononic crystal acoustic device, and the phononic crystal is located in the center of the device; b is 2 phononic crystal acoustic devices, and the adjacent phononic crystals are spaced apart by 15mm; c is 3 phononic crystal acoustic devices, and the adjacent phononic crystals are spaced apart by 15mm; d is 4 phononic crystal acoustic devices, and the adjacent phononic crystals are spaced apart by 15mm. It can be obviously seen that the EVA layer with 4 phononic crystals + PU layer with cavity assembled into the acoustic device has the highest sound insulation effect.
[0047] From the above, it is found that the phononic crystal height (thickness) is 15mm, and the number of phononic crystals is 4x4, and the sound insulation effect of example 1 is the best. The sound insulation effect of example 1 is compared with the traditional acoustic materials in comparative examples 1-3.
[0048] Comparative example 1
[0049] Pure PU structure, without phononic crystal, without EVA thin layer, and without cavity in the PU foaming layer. The length, width and height of the PU layer are the same as those of example 1.
[0050] Comparative example 2
[0051] As shown in Figure 4 , the acoustic device is assembled by the EVA layer 1 with phononic crystal and the PU foaming layer 7 without cavity, wherein the length, width and height of the EVA thin layer 4, the length, width and height of the phononic crystal 3, the spacing between adjacent phononic crystals, and the length, width and height of the PU foaming layer 7 are the same as those of example 1, except that the PU foaming layer has no cavity.
[0052] Comparative example 3
[0053] As shown in Figure 5 , the acoustic device is assembled by the PU foaming layer 8 with cavity but without hole and the EVA layer or EVA thin layer 4 without phononic crystal, wherein the length, width and height of the cavity 3, the spacing between adjacent cavities, the length, width and height of the PU foaming layer, and the length, width and height of the EVA thin layer 4 are the same as those of example 1, except that there is only the EVA thin layer 4 without phononic crystal 5.
[0054] The insertion loss comparison results of example 1 and comparative examples 1-3 are shown in Figure 6The utility model provides a phonon crystal - cavity compound structure, it includes the phonon crystal structure and the cavity structure, the phonon crystal structure is made of EVA phonon crystal, the cavity structure is made of PU, the phonon crystal structure is connected with the cavity structure. Figure 6 It is known that the phonon crystal-cavity composite structure provided by the utility model has a great improvement in low-frequency sound insulation performance compared with the traditional structure of pure PU, the phonon crystal structure (without cavity) and the cavity structure (without EVA phonon crystal), wherein the insertion loss of the phonon crystal-cavity composite structure can be improved by 5-10 dB, and the highest can reach 15 dB.
Claims
1. A prefabricated acoustic device for sound absorption and insulation, characterized in that... It includes an EVA layer with a phonon crystal and a PU foam layer with a cavity. The PU foam layer with the cavity has holes corresponding to the size of the phonon crystal in the EVA layer with the phonon crystal. The phonon crystal is seamlessly embedded in the holes of the PU foam layer.
2. The assembled acoustic device for sound absorption and insulation as described in claim 1, characterized in that... The phonon crystal and the cavity are arranged periodically.
3. The assembled acoustic device for sound absorption and insulation as described in claim 2, characterized in that... In the EVA with phonon crystals, the spacing between adjacent phonon crystals is 5 to 15 mm.
4. The assembled acoustic device for sound absorption and insulation as described in claim 2, characterized in that... In the PU foam layer with cavities, the interval between adjacent cavities is 5 to 15 mm.
5. A prefabricated acoustic device for sound absorption and insulation as described in claim 1, characterized in that... In the EVA layer with phononic crystal, the length, width and height of the phononic crystal are (10-15mm), (10-15mm) and (5-8mm) respectively.
6. The assembled acoustic device for sound absorption and insulation as described in claim 1, characterized in that... In the PU foam layer with cavities, the length, width and height of the cavities are (10-15mm), (10-15mm) and (5-8mm) respectively.
7. The assembled acoustic device for sound absorption and insulation as described in claim 1, characterized in that... The number of phonon crystals is 4*4.
8. The assembled acoustic device for sound absorption and insulation as described in claim 1, characterized in that... The EVA layer with phonon crystal uses EVA with an elastic modulus of 2*10. 8 Pa, density is 1500 kg / m³ 3 .
9. A prefabricated acoustic device for sound absorption and insulation as described in claim 1, characterized in that... The PU foam layer with cavities uses PU with an elastic modulus of 8*10. 4 Pa, density 60 kg / m³ 3 The damping loss factor is 0.15.