KR20240082057A - Floor impact noise reduction panel using acoustic black hole - Google Patents

Abstract

The present invention relates to an interlayer noise reduction panel using acoustic black holes. More specifically, acoustic black holes, whose thickness decreases in a power-law form to prevent reflection of waves, have been studied to reduce vibration of plates in the mechanical field. The goal is to provide an acoustic black hole panel that can reduce noise. The interfloor noise reduction panel using acoustic black holes according to an embodiment of the present invention is made of one material, includes a structure that gradually becomes thinner, is attached to the ceiling, and has a one-dimensional or a panel in the form of a two-dimensional acoustic black hole, including one or more contact parts for contacting a support, and having a separation distance from the support other than the contact parts; and a damping layer that dissipates noise or vibration inside the panel. ) may include.

Description

Interfloor noise reduction panel using acoustic black hole {FLOOR IMPACT NOISE REDUCTION PANEL USING ACOUSTIC BLACK HOLE}

The present invention relates to a noise reduction panel, and more specifically, to an interfloor noise reduction panel using an acoustic black hole.

Acoustic black hole (ABH) is a technology for passive vibration control recently developed in the structural dynamics and acoustic vibration community.

The acoustic black hole structure was first formally defined by Mironov and named acoustic black hole by Krylov, and its use as a vibration damper was suggested in particular.

The original definition of this acoustic black hole beam structure refers to a structure in which the thickness (h) gradually becomes thinner from the base to the end of a cantilever beam.

At this time. Since the phase velocity (Cb) of the bending wave propagating within the acoustic black hole beam structure is proportional to the square root of the thickness as shown in Equation I below, the acoustic black hole beam structure whose thickness gradually becomes thinner toward the end has the The propagation speed becomes very small.

(Equation I)

(Equation II)

Here, E is Young's modulus, which is the elastic modulus of the material constituting the beam, ρ is the density of the material, ν is the Poisson's ratio of the material, and ω is the angular frequency of the bending wave.

1.029)이다. 폭 방향의 두께 변화가 주 관점인 본 발명에서는 적용의 확장성을 고려하여 판의 식을 함께 사용한다.The above (Equation I) is an expression of the phase velocity of the bending wave in the beam, and (Equation II) is an expression of the phase velocity of the bending wave in the plate. For most beams made of metallic materials, the Poisson's ratio is 0.33, and the difference due to this is generally within 3% (

1.029). In the present invention, where the change in thickness in the width direction is the main viewpoint, the plate equation is used in consideration of the expandability of application.

In summary, in Figure 1, the thickness h(x) changes from the base of the cantilever, which is the reference position (x=0, 100), to the position of the end (x _tip ), and the maximum thickness of the base (100) It is generally thin along the m difference curve up to the size of h _tip , which is the thickness, and the most ideal acoustic black hole should have h _tip = 0.

However, when this acoustic black hole structure is actually manufactured, the thickness of the end cannot be 0, and as the end is manufactured with the thinnest thickness possible, the problem of increasing manufacturing difficulty arises.

Since the issue of noise between floors has caused many social conflicts since the early 2000s, continuous efforts have been made to reduce noise between floors, such as applying high-performance cushioning materials and reducing the thickness of slabs, but the problem of heavy impact sounds such as footsteps still remains. In particular, as the time spent living at home increases due to COVID-19, problems related to noise between floors have been occurring frequently, and the government has announced that it will implement a post-confirmation system for noise between floors to solve this problem.

The technical problem to be solved by the present invention relates to an inter-floor noise reduction panel using an acoustic black hole. More specifically, the acoustic black hole, which prevents reflection of waves by reducing the thickness in the form of a power law, reduces the vibration of plates in the mechanical field. Research has been conducted to reduce inter-floor noise by providing a black hole panel that can reduce inter-floor noise.

The present invention seeks to provide a flooring or ceiling material that can reduce the level of weight impact sound felt from the lower floor by applying the acoustic black hole concept.

This research was conducted with support from the Smart Underwater Tunnel System Research Center project and the G-CORE operation project.

As a means of solving the above technical problems, in the inter-floor noise reduction panel using acoustic black holes, the inter-floor noise reduction panel using acoustic black holes is made of one material, includes a gradually thinner structure, and is attached to the ceiling, A panel in the form of a one-dimensional or two-dimensional acoustic black hole, including one or more contact parts for contacting a support, and having a separation distance from the ceiling other than the contact parts; and a buffer layer (damping) that dissipates noise or vibration inside the panel. layer).

In one embodiment of the present invention, the inter-floor noise reduction panel using the acoustic black holes may have irregular spacing and size of the acoustic black holes so that the contact portion is located in a place where vibration is severe.

In one embodiment of the present invention, as the panel extends from one end to the other end, the thickness may decrease according to the equation below.

In the above equation, h(x) is the thickness of the panel, m is a positive real number, x is the distance from the other end of the panel, ε is a constant, and h _tip represents the thickness at the other end of the panel.

In one embodiment of the present invention, the acoustic black hole is one-dimensional, with a straight groove formed, or

A two-dimensional hemispherical groove may be formed.

In one embodiment of the present invention, one material forming the acoustic black hole panel is rubber, polyurethane, ABS (acrylonitrile butadiene styrene copolymer) resin, PLA (Poly Lactic Acid), metal, fiber, and mortar. , may be composed of any one selected from concrete.

A panel made of the above material may be formed as a single layer.

In one embodiment of the present invention, the material forming the buffer layer attached to the acoustic black hole is sponge, rubber, EPS (Expanded PolyStyrene), EVA (Ethylene-Vinyl Acetate copolymer), styrofoam, and It may be composed of one selected from epoxy resin and mortar.

In one embodiment of the present invention, the acoustic black hole panel may be installed on the entire ceiling or may be attached only to the vibrating part that generates noise through vibration analysis.

According to the present invention, heavy impact noise has been continuously causing social problems since the early 2000s, and is known to be a difficult problem to solve in the building and construction industry. By using the weight impact sound reduction panel applying the acoustic black hole effect of the present invention, the wave incident on the acoustic black hole panel cannot escape due to the slowing speed, thereby reducing the energy transmitted to the lower floor, thereby reducing the level of noise felt in the lower floor. there is.

Additionally, by applying an acoustic black hole, the pattern layer in the hard panel can be formed into a single layer to refract and reflect sound waves, thereby reducing the thickness of the panel and effectively dissipating noise.

Additionally, a sound-absorbing material is formed that can absorb noise passing through the hard panel, effectively reducing noise.

In addition, it can be applied to existing buildings, which has the effect of reducing costs.

In addition, it has the advantage of low construction costs, so it can be economically effective.

Figure 1 is the basic structure of an acoustic black hole beam.
Figure 2 is an enlarged cross-sectional view of the inter-floor noise reduction hard panel.
Figure 3a shows a typical 1D ABH with a wedge-shaped beam, Figure 3b shows a spiral ABH, Figure 3c shows an acoustic waveguide with varying wall impedance made of branching disks of increasing diameter, Figure 3d shows a 2D made with an axisymmetric fit. ABH, Figure 3e shows one-sided ABH slots, and Figure 3f shows two-sided ABH slots.
Figure 4 is a diagram schematically showing an attenuation material attached to an acoustic black hole portion according to an embodiment of the present invention.
Figures 5 and 6 are schematic diagrams of a heavy impact sound reduction panel using an acoustic black hole shape of one-dimensional and two-dimensional structures, respectively.
Figure 7 is a diagram schematically showing a buffer panel installed between the slab and the finishing mortar.
Figures 8 and 9 are diagrams schematically showing an acoustic black hole installed in a bottom plate sleeve according to an embodiment of the present invention.
10 to 12 are views showing a contact portion connected to one or more ceilings according to an embodiment of the present invention.
Figure 13 is a diagram showing that the bottom, top, or both sides of the panel are thinned, according to an embodiment of the present invention.

Aspects of the present invention will hereinafter be described in more detail with reference to the accompanying drawings. However, the invention may be embodied in many different forms, and should not be construed as limited to the aspects set forth herein. Rather, the above aspects serve to render the invention more thorough and complete, and fully convey the scope of the invention to those skilled in the art. Although terms referring to first, second, etc. may be used herein to describe various components, it will be understood that the components are not limited to these terms. However, these terms are only used to distinguish one component from another. As used herein, the term “and/or” includes all inferable combinations of one or more related listed items. Particularly relative terms such as "bottom, selected, other special, remainder, opposite, and on" are used to briefly describe a selected component, the relative relationship of another component to a shape, or the shape shown in the drawings. It can be used for simplification. And, the use of terminology herein is merely to describe particular aspects and is not intended to limit the invention.

When an external force acts on a plate, a wave propagates along the plate, and the speed of the wave decreases as the thickness of the plate becomes thinner. If an acoustic black hole (ABH) whose thickness decreases sequentially is connected to the side of the plate, the wave entering the acoustic black hole continues to slow down and does not reach the end of the acoustic black hole. Therefore, theoretically, the waves entering the acoustic black hole are reflected and the vibration of the existing plate is attenuated.

The development of lightweight and rigid panels with a damping effect against high vibrations is a long-standing challenge in the field of mechanical engineering. Composite materials have been attempted as an effective response to this problem. The present invention seeks to solve the problem based on structured materials. Here the properties of the materials can be obtained as a result of strategically positioned geometric or material insertions.

Inserting an acoustic black hole is a kind of trap for local flexural elastic waves based on local heterogeneities, and can achieve effective passive structural vibration control. Looking at the characteristics of a bending wave traveling on a beam terminated by a wedge with a thickness profile that has a power law decreasing property, a termination that can be completely absorbed from an analytical point of view is achieved. can do. The velocity of the incoming bending wave at the tip of a wedge of decreasing thickness may decrease, reaching zero, so that the wave ultimately never reaches the tip of the wedge and is never reflected.

If the wedge is not coupled from an energy-consuming perspective, the elastic waves are trapped inside the wedge, and the given mechanical energy must be conserved. So the particle displacement grows unconstrained, and the end point of the wedge becomes a point of singularity. However, if most digging wedges are coupled with energy-consuming mechanisms, the waves can be absorbed. Whether or not it is coupled with an energy-consuming mechanism, elastic waves enter the wedge and are never reflected. Therefore, it has a zero reflection coefficient.

Additionally, the concept of retarding structures can be extended to two dimensions through insertion into axisymmetric circular pits. Along with the retarding wedge, circular tapered pits can slow down and function as omni-directional wave absorbers.

In the ideal case, but in the absence of a divergence mechanism, the center of an acoustic black hole (ABH) would act as a singularity of the particle displacement which goes to infinity. From this perspective, similar to the properties of an optical black hole, the concept of an acoustic black hole, also called a vibration acoustic black hole, may be more appropriate.

Referring to FIG. 2, the pattern layer 110 of the hard panel 10 is a patterned layer that is regularly or randomly arranged in the second and third dimensions by varying the density or elastic modulus within the base layer 210. define.

Figure 2 is an enlarged cross-sectional view of the base layer 210 of the wall and floor structure for reducing inter-floor noise. As sound wave energy transmitted from the vertical passes through a patterned medium, the sound wave progresses based on the propagation speed or sound impedance difference depending on the medium. Changes direction horizontally. By using the refraction phenomenon of the sound wave (WS), the direction of movement of the sound wave (WS) is converted horizontally, thereby reducing the noise transmitted to the lower part and changing the direction of movement of the sound wave as horizontally as possible to move the sound wave (WS). As , increases, the horizontally transmitted sound wave (WS) is dissipated.

In addition, at the boundary of the medium, part of the sound wave (WS) is transmitted and another part is reflected, thereby increasing the travel distance of the sound wave (WS), thereby maximizing the energy dissipation phenomenon. There is a large difference in propagation speed when sound waves (WS) move from a substance with a slow propagation speed to a substance with a fast propagation speed, or when they move from a fast substance to a slow substance. Therefore, when the sound wave (WS) moves from a dense medium to a sparse medium or from a sparse medium to a dense medium, the larger the propagation speed or acoustic sound pedance difference, the larger the refraction angle. Therefore, when the sound wave (WS) moves from a dense medium to a sparse medium or from a sparse medium to a dense medium, the larger the propagation speed or acoustic impedance difference, the more preferable, and the order in which the sound wave (WS) passes through the pattern layer 110 is limited to this. I never do that.

A typical example employed to achieve the ABH structure is presented in Figure 3.

Figure 3a shows a typical 1D ABH with a wedge-shaped beam, Figure 3b shows a spiral ABH, Figure 3c shows an acoustic waveguide with variable wall impedance made of branched disks of increasing diameter, and Figure 3d shows an axisymmetric pit. 2D ABH made with, Figure 3e shows one-sided ABH slots, Figure 3f shows two-sided ABH slots.

The basic idea behind the concept of ABH can be seen as a delay structure that can create termination by 0 reflection. In this case, we can consider bending waves in a tapering beam, which can be extended to an acoustic tube with an axially varying thickness impedance. This practice is associated with the ideal ABH effect without dissipation.

In the development of the ABH effect, another important step involves the extension of the absorbing wedge concept to 2D configurations. More specifically, a power law profile can be applied to integrate the absorber layer effect at the surface of the plate.

This latter case is referred to as an embedded ABH trace. It has several characteristics of a scattering device with a long, thin tip, and can be expected to provide effects such as low reflectivity, increased local attenuation, and energy harvesting.

In a general one-dimensional form, an acoustic black hole can be realized as a beam-like structure by varying spatial thickness and damping properties.

Such a system is a complex non-uniform wave guide and can be represented by five or six models of increasing complexity.

The phase and group velocities of flexural waves within a beam decrease with decreasing thickness. So when the thickness changes smoothly and reaches zero, the corresponding wave velocities can become zero. So the wave cannot reach the end of the wedge and cannot be reflected. The thickness change for this delay structure can be given by the following [Equation 1].

In [Equation 1], m is a real constant defining the power law profile, x is the axial coordinate along the axial wedge, and ε is a constant. The class for the profile was chosen to satisfy sufficient smoothness, and the change in bending wave number should be sufficiently small for the corresponding length of the wave.

When [Equation 1] for this thickness change is applied to the present invention, it is as follows.

An inter-floor noise reduction panel using an acoustic black hole is made of one material, includes a structure that gradually becomes thinner, is attached to the ceiling, is in the form of a one-dimensional or two-dimensional acoustic black hole, and has one or more contact parts for contacting a support. It may include a panel having a separation distance from the support other than the contact portion, and a damping layer that dissipates noise or vibration within the panel.

The support may be a ceiling.

The basic structure for an acoustic black hole is as shown in Figure 1 as described above. It is formed in a structure where the thickness gradually becomes thinner as it extends from the root part (100) to the tip (200).

When an external force acts on a plate, a wave propagates along the plate, and the speed of the wave decreases as the plate becomes thinner. At this time, if an acoustic black hole (ABH) whose thickness gradually decreases is connected to the side of the plate, the wave traveling into the acoustic black hole continues to slow down, preventing it from reaching the end of the acoustic black hole.

Therefore, in theory, the vibration of the existing plate is attenuated because the waves entering the acoustic black hole are reflected and cannot return.

In order for the acoustic black hole to be effective in reducing vibration or noise, the thickness (h(x)) of the side of the acoustic black hole must be in the form of a power function where m is 2 or more, as shown in Equation 2. An example of the shape is as shown in Figure 1. In Figure 1, it includes a root portion 100 and an end portion 200.

In [Equation 2] above, m is a real constant defining the power law profile, x is the axial coordinate along the axial wedge, and ε is a constant. In [Equation 2], h _tip is the thickness at the tip of x=x _tip , and should be 0 in the most ideal acoustic black hole.

In theory, if the thickness at the end of an acoustic black hole is 0, reflected waves disappear, but in reality, since the thickness cannot be made 0, some waves are reflected. Because of this, acoustic black hole technology was difficult to utilize practically for a while. However, such a problem can be overcome by attaching a material that can provide an attenuation effect to the acoustic black hole portion, as shown in FIG. 4, to reduce reflected waves.

Figure 4 is a diagram schematically showing an attenuation material attached to an acoustic black hole portion according to an embodiment of the present invention.

The basic principles of acoustic black holes have been explained through FIGS. 1 to 4.

In the present invention, the acoustic black hole effect can be used to reduce heavy impact sound through the ceiling or floor of a building.

Figures 5 and 6 are schematic diagrams of a heavy impact sound reduction panel using an acoustic black hole shape of one-dimensional and two-dimensional structures, respectively.

Referring to FIG. 5, the one-dimensional acoustic black hole structure may have a one-dimensional, straight groove formed therein.

Referring to FIG. 6, the two-dimensional acoustic black hole structure may be one in which hemispherical grooves are formed two-dimensionally.

As shown in Figures 5 and 6, to improve the effect of the basic panel (straight groove or two-dimensional hemispherical groove), a damping layer is attached to the thinner part of the panel, as shown in Figure 4.

Figure 7 is a diagram schematically showing a buffer panel installed between the slab and the finishing mortar.

Referring to Figure 7, the existing buffer panel was installed in the layer between the slab and the finishing mortar as shown in Figure 7, making it difficult to apply to existing public housing.

However, in the case of the inter-floor noise reduction panel using an acoustic black hole according to an embodiment of the present invention, it can be installed inside the floor structure like an existing panel, but it can also be installed on the ceiling of the lower floor, as shown in FIGS. 8 and 9.

Figures 8 and 9 are diagrams schematically showing an acoustic black hole installed in a bottom plate sleeve according to an embodiment of the present invention.

One embodiment of the present invention includes a panel as shown in Figures 5 and 6 and a structure attachable to a lower floor ceiling as shown in Figures 8 and 9.

10 to 13 are views showing a contact portion connected to one or more ceilings according to an embodiment of the present invention.

Referring to FIGS. 10 to 12, in one embodiment of the present invention, the panels have one or more contact portions connected to the ceiling as shown in FIGS. 10, 11, and 12, and have a separation distance from the ceiling except for the contact portions.

Figure 13 is a diagram showing that the bottom, top, or both sides of the panel are thinned, according to an embodiment of the present invention.

As shown in Figures 10 and 13, the bottom, top, or both sides of the panel can be thinned, and even in this case, the thickness is thinned in the form of a power function of order 2 or higher. One or more one-dimensional or two-dimensional acoustic black hole parts (thinning parts) may exist in the panel.

Acoustic black hole panels can not only be installed on the entire ceiling, but can also be attached only to vibrating parts that cause noise through vibration analysis.

In this case, the panel can be installed in a place with severe vibration. If the size or shape of the panel is not consistent in the spacing of parts with high vibration, the size and spacing of the acoustic black hole portion within the panel may be inconsistent.

The material forming the acoustic black hole panel may be composed of any one selected from rubber, polyurethane, ABS (acrylonitrile butadiene styrene copolymer) resin, PLA (Poly Lactic Acid), metal, fiber, mortar, and concrete.

These materials can be manufactured mechanically, by using a 3D printer, or by pouring the shape into the formwork during construction.

The material forming the buffer layer attached to the acoustic black hole is selected from sponge, rubber, EPS (Expanded PolyStyrene), EVA (Ethylene-Vinyl Acetate copolymer), styrofoam, epoxy resin, and mortar. It may consist of any one

100: root
200: tip
110: Pattern layer
210: base layer
10: Hard panel

Claims (11)

In the noise reduction panel,
It is made of one material and contains a structure that becomes increasingly thinner,
Has one-dimensional or two-dimensional acoustic black hole characteristics,
Comprising one or more contact portions for contacting the support,
A noise reduction panel, characterized in that it has a separation distance from the support other than the contact portion. According to paragraph 1,
The support is a ceiling, and the noise reduction panel is characterized in that it reduces noise. According to paragraph 1,
A noise reduction panel, characterized in that the panel made of the above material is formed as a single layer. According to paragraph 1,
A noise reduction panel further comprising a damping layer that dissipates noise or vibration within the panel. According to paragraph 1,
The noise reduction panel is,
A noise reduction panel characterized in that it can have irregular spacing and size so that the contact portion is located at a predetermined location. According to paragraph 1,
A noise reduction panel whose thickness decreases according to the equation below as the panel extends from one end to the other end.

(h(x) is the thickness of the panel, m is a positive real number, x is the distance from the other end of the panel, ε is a constant, h _tip is the thickness at the other end of the panel) According to paragraph 1,
One-dimensionally, a straight groove is formed, or
A noise reduction panel characterized by a two-dimensional, hemispherical groove formed. According to paragraph 1,
The material forming the panel is:
A noise reduction panel composed of one selected from rubber, polyurethane, ABS (ABS resin, acrylonitrile butadiene styrene copolymer) resin, PLA (Poly Lactic Acid), metal, fiber, mortar, and concrete. According to paragraph 3,
The material forming the buffer layer is,
Sponge, rubber, EPS (Expanded PolyStyrene), EPP (Expanded PolyPropylene). A noise reduction panel composed of one selected from EVA (Ethylene-Vinyl Acetate copolymer), polyurethane, styrofoam, epoxy resin, mortar, aluminum, and iron. According to paragraph 1,
The panel is,
A noise reduction panel that can be installed on the entire ceiling or attached only to the vibrating part that causes noise through vibration analysis. According to paragraph 1,
A noise reduction panel, characterized in that the panel includes a structure attachable to a lower floor ceiling.

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