JP6190291B2 - Sound absorption panel - Google Patents
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Description
本発明は、道路や線路の近傍、特に、新幹線などの高速鉄道車両が走行する線路の近傍に設けられて、騒音を低減させる吸音パネルに関する。 The present invention relates to a sound-absorbing panel that is provided in the vicinity of roads and tracks, particularly in the vicinity of tracks on which high-speed rail vehicles such as Shinkansen travel, to reduce noise.
道路や線路の近傍に防音壁を設けて、騒音を低減させることが行われている。そして、道路の近傍に設置する防音壁には、従来、グラスウールなどの繊維を使った吸音材が使用されている。ここで、新幹線などの高速鉄道車両が走行する線路の近傍に設置した防音壁には、車両通過時に列車風圧がかかる。そのため、道路用の防音壁に使用しているグラスウールなどの繊維を使った吸音材を、高速鉄道車両が走行する線路用の防音壁に適用すると、長期間の使用による劣化具合によっては、繰り返し受ける風圧によって繊維が飛散する恐れがある。 Noise reduction is carried out by providing a soundproof wall in the vicinity of a road or a track. Conventionally, sound absorbing materials using fibers such as glass wool have been used for soundproof walls installed in the vicinity of roads. Here, the train wind pressure is applied to the soundproof wall installed in the vicinity of the track on which the high-speed railway vehicle such as the Shinkansen travels. Therefore, if a sound absorbing material using fiber such as glass wool used for a road noise barrier is applied to a noise barrier for a track on which a high-speed railway vehicle runs, it will be repeatedly subjected to deterioration due to long-term use. There is a risk that the fibers may be scattered by wind pressure.
そこで、特許文献１には、筐体の内部空間に、多数の貫通孔を有する第１多孔板及び第２多孔板で仕切られた複数の空間が形成された吸音構造体が開示されている。音源からの音が多孔板の貫通孔から空間内に進入すると、共鳴が発生し、貫通孔部における空気の振動によって、貫通孔の内壁と空気との間に摩擦が生じ、振動エネルギーの一部が熱エネルギーに変換されて吸音作用が生じる。そして、この吸音構造体は金属製で耐候性があり、グラスウールなどの繊維を使用していないため、長期間の使用による繊維の飛散や吸音性能の劣化がない。 Therefore, Patent Document 1 discloses a sound absorbing structure in which a plurality of spaces partitioned by a first perforated plate and a second perforated plate having a large number of through holes are formed in an internal space of a housing. When sound from the sound source enters the space from the through hole of the perforated plate, resonance occurs, and friction between the inner wall of the through hole and the air occurs due to vibration of the air in the through hole, and part of the vibration energy Is converted into thermal energy to produce a sound absorbing effect. This sound absorbing structure is made of metal and has weather resistance, and does not use fibers such as glass wool. Therefore, there is no scattering of fibers and deterioration of sound absorbing performance due to long-term use.
しかしながら、特許文献１に記載の吸音構造体は、多孔板の板厚が０．１ｍｍ程度であるため、耐力が低い。よって、この吸音構造体を高速鉄道車両が走行する線路の近傍に設置した場合、長期間の列車風圧による繰り返し荷重によって破壊される可能性が高い。 However, the sound-absorbing structure described in Patent Document 1 has a low yield strength because the thickness of the porous plate is about 0.1 mm. Therefore, when this sound absorbing structure is installed in the vicinity of a track on which a high-speed railway vehicle travels, there is a high possibility that the sound absorbing structure will be destroyed by repeated loads due to long-term train wind pressure.
そこで、吸音構造体の耐力を向上させるために、多孔板をリブで補強することが考えられる。しかし、この場合、貫通孔の一部がリブで覆われるので、吸音率が低下するという問題がある。 Therefore, in order to improve the yield strength of the sound absorbing structure, it is conceivable to reinforce the porous plate with ribs. However, in this case, since a part of the through hole is covered with the rib, there is a problem that the sound absorption coefficient is lowered.
本発明の目的は、耐力を向上させながら、吸音性能を維持することが可能な吸音パネルを提供することである。 An object of the present invention is to provide a sound absorbing panel capable of maintaining sound absorbing performance while improving proof stress.
本発明は、音源からの音を吸音する吸音パネルであって、多数の貫通孔を有する多孔板と、前記多孔板との間に所定の間隔をあけて前記多孔板に対向配置された背面板と、前記多孔板と前記背面板とで挟まれた空間を囲繞する枠体と、前記多孔板の前記背面板側の面に所定の間隔で取り付けられた複数の補強リブと、を有し、隣り合う前記補強リブ間の距離ａと、前記多孔板の板厚ｔとが以下の式（１）を満足しているとともに、前記多孔板の開口率βが以下の式（２）を満足していることを特徴とする。
ａ／ｔ＜Ｋ１×（Ａ／ｐ０）1/2 ・・・式（１）
β＝（Ｂ（１−１／Ｎ）／ａ＋１）×α×Ｋ２ ・・・式（２）
ここで、Ａは前記多孔板の許容応力、ｐ０は前記多孔板に作用する設計上の荷重、Ｋ１＝０．９３、Ｂは前記補強リブの幅、Ｎは前記補強リブにより前記多孔板の面が分割された数、αは前記補強リブを設けずに吸音設計した場合の前記多孔板の設計開口率、Ｋ２は係数である。なお、多孔板の許容応力の値は、例えば後述の「鉄道構造物等設計標準・同解説」などに示される計算式から決まる。
The present invention is a sound-absorbing panel that absorbs sound from a sound source, and a perforated plate having a large number of through holes, and a back plate disposed opposite to the perforated plate with a predetermined interval between the perforated plate And a frame body that surrounds a space sandwiched between the porous plate and the back plate, and a plurality of reinforcing ribs attached to the surface on the back plate side of the porous plate at a predetermined interval, The distance a between the adjacent reinforcing ribs and the thickness t of the porous plate satisfy the following formula (1), and the aperture ratio β of the porous plate satisfies the following formula (2). It is characterized by.
a / t <K1 × (A / p0) 1/2 Formula (1)
β = (B (1-1 / N) / a + 1) × α × K2 Formula (2)
Here, A is an allowable stress of the porous plate, p0 is a design load acting on the porous plate, K1 = 0.93, B is a width of the reinforcing rib, and N is a surface of the porous plate by the reinforcing rib. Is the divided number, α is the design aperture ratio of the perforated plate in the case of sound absorption design without providing the reinforcing rib, and K2 is a coefficient. Note that the permissible stress value of the perforated plate is determined, for example, from a calculation formula shown in “Railway Structure Design Standards / Description” described later.
また、本発明は、音源からの音を吸音する吸音パネルであって、多数の貫通孔を有する多孔板と、前記多孔板との間に所定の間隔をあけて前記多孔板に対向配置された背面板と、前記多孔板と前記背面板とで挟まれた空間を囲繞する枠体と、前記多孔板の前記背面板側の面に所定の間隔で取り付けられた複数の補強リブと、を有し、隣り合う前記補強リブ間の距離ａと、前記多孔板の板厚ｔとが以下の式（１）を満足しているとともに、板厚ｔ’である前記多孔板に前記補強リブを設けた場合の前記多孔板の開口率β’が以下の式（３）を満足し、且つ、板厚ｔである前記多孔板の開口率γが以下の式（４）を満足していることを特徴とする。
ａ／ｔ＜Ｋ１×（Ａ／ｐ０）1/2 ・・・式（１）
β’＝（Ｂ（１−１／Ｎ）／ａ＋１）×α×１ ・・・式（３）
γ＝ｔ／ｔ’×β’×Ｋ３ ・・・式（４）
ここで、Ａは前記多孔板の許容応力、ｐ０は前記多孔板に作用する設計上の荷重、Ｋ１＝０．９３、Ｂは前記補強リブの幅、Ｎは前記補強リブにより前記多孔板の面が分割された数、αは前記補強リブを設けずに吸音設計した場合の前記多孔板の設計開口率、ｔ’は前記補強リブを設けずに吸音設計した場合の前記多孔板の設計板厚、Ｋ３は係数であって、ｔ’＜ｔである。
Further, the present invention is a sound absorbing panel that absorbs sound from a sound source, and is disposed opposite to the porous plate with a predetermined interval between the porous plate having a large number of through holes and the porous plate. A back plate, a frame surrounding a space sandwiched between the porous plate and the back plate, and a plurality of reinforcing ribs attached to a surface of the porous plate on the back plate side at a predetermined interval. The distance a between the reinforcing ribs adjacent to each other and the plate thickness t of the porous plate satisfy the following formula (1), and the reinforcing rib is provided on the porous plate having the plate thickness t ′. When the aperture ratio β ′ of the porous plate satisfies the following formula (3), and the aperture ratio γ of the porous plate, which is the plate thickness t, satisfies the following formula (4): Features.
a / t <K1 × (A / p0) 1/2 Formula (1)
β ′ = (B (1-1 / N) / a + 1) × α × 1 Formula (3)
γ = t / t ′ × β ′ × K3 (4)
Here, A is an allowable stress of the porous plate, p0 is a design load acting on the porous plate, K1 = 0.93, B is a width of the reinforcing rib, and N is a surface of the porous plate by the reinforcing rib. , Α is the design aperture ratio of the porous plate when the sound absorption design is performed without providing the reinforcing rib, and t ′ is the design plate thickness of the porous plate when the sound absorption design is performed without providing the reinforcing rib. , K3 is a coefficient, and t ′ <t.
上記の式（１）は、多孔板を両端が支持された１次元のはりとみなしたときに、このはりに列車風圧を模擬した等分布荷重が掛かった際に最大曲げモーメントを受けるはり中央部における応力値と、多孔板の材料の耐力から決まる許容応力との関係を表している。そして、この式（１）を満足するように、隣り合う補強リブ間の距離ａと、多孔板の板厚ｔとを設計することにより、設計荷重（多孔板に作用する設計上の荷重）ｐ０に対して多孔板の許容応力Ａを満たすことができる。これにより、高速鉄道車両の通過時の列車風圧などに耐えることができるように、吸音パネルの耐力を向上させることができる。 When the above equation (1) is considered to be a one-dimensional beam with both ends supported, the center part of the beam that receives the maximum bending moment when a uniform load simulating train wind pressure is applied to this beam The relationship between the stress value at and the allowable stress determined from the proof stress of the material of the perforated plate is shown. The design load (design load acting on the porous plate) p0 is designed by designing the distance a between the adjacent reinforcing ribs and the plate thickness t of the porous plate so as to satisfy the formula (1). In contrast, the permissible stress A of the perforated plate can be satisfied. Thereby, the proof stress of a sound absorption panel can be improved so that it can endure the train wind pressure etc. at the time of passage of a high-speed rail vehicle.
しかし、多孔板に複数の補強リブを取り付けると、貫通孔の一部が補強リブで塞がれることで吸音面積が減少するので、補強リブを設けずに多孔板と空気層のみの系で吸音設計した場合の多孔板の設計開口率αのままでは、吸音パネルの吸音性能が低下する。そこで、上記の式（２）を満足するように多孔板の開口率βを設計することにより、多孔板に補強リブを取り付けた場合であっても、吸音パネルの吸音性能を維持することができる。 However, if a plurality of reinforcing ribs are attached to the perforated plate, the sound absorbing area is reduced by blocking a part of the through-holes with the reinforcing ribs. If the designed aperture ratio α of the perforated plate is designed, the sound absorbing performance of the sound absorbing panel is lowered. Therefore, by designing the aperture ratio β of the perforated plate so as to satisfy the above formula (2), the sound absorbing performance of the sound absorbing panel can be maintained even when the reinforcing rib is attached to the perforated plate. .
また、吸音パネルの耐力を向上させるには、多孔板の板厚を厚くすればよいが、設計板厚ｔ’で吸音設計を実施し、設計開口率αまたは設計板厚ｔ’における開口率β’で吸音性能を満たしている場合、即ち、式（３）を満足している場合、多孔板２の板厚をｔ’からｔに厚くすると、貫通孔を空気が通りにくくなるため、設計開口率αまたは設計板厚ｔ’における開口率β’のままでは吸音性能が低下する。そこで、上記の式（４）を満足するように多孔板の開口率γを設計することにより、多孔板に補強リブを取り付け、さらに多孔板の板厚を厚くした場合であっても、吸音パネルの吸音性能を維持することができる。 In order to improve the proof stress of the sound absorbing panel, the thickness of the perforated plate may be increased. However, the sound absorbing design is performed with the design plate thickness t ′, and the design aperture ratio α or the aperture ratio β at the design plate thickness t ′. When the sound absorbing performance is satisfied with ', that is, when the expression (3) is satisfied, increasing the thickness of the porous plate 2 from t ′ to t makes it difficult for air to pass through the through-hole. If the rate α or the aperture ratio β ′ at the design plate thickness t ′ remains as it is, the sound absorption performance is lowered. Therefore, even when the reinforcing rib is attached to the porous plate and the thickness of the porous plate is increased by designing the aperture ratio γ of the porous plate so as to satisfy the above formula (4), the sound absorbing panel The sound absorption performance can be maintained.
これにより、耐力を向上させながら、吸音性能を維持することができる。 Thereby, sound absorption performance can be maintained while improving proof stress.
以下、本発明の好適な実施の形態について、図面を参照しつつ説明する。 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
［第１実施形態］
（吸音パネルの構成）
本発明の第１実施形態による吸音パネル１は、音源からの音を吸音するものであって、正面図である図１Ａ、および、図１ＡのＡ−Ａ断面図である図１Ｂに示すように、表面多孔板２ａと、背面板３と、枠体４と、内部多孔板２ｂと、補強リブ５と、を有している。吸音パネル１は、表面多孔板２ａが音源に面するようにして配置される。
[First Embodiment]
(Configuration of sound absorbing panel)
The sound absorbing panel 1 according to the first embodiment of the present invention absorbs sound from a sound source, as shown in FIG. 1A, which is a front view, and FIG. 1B, which is a cross-sectional view along AA in FIG. 1A. The front porous plate 2a, the back plate 3, the frame 4, the internal porous plate 2b, and the reinforcing rib 5 are provided. The sound absorbing panel 1 is disposed so that the surface porous plate 2a faces the sound source.
表面多孔板２ａおよび内部多孔板２ｂは、アルミニウム等の金属製であって、多数の円形状の貫通孔を有している。なお、貫通孔の形状は、円形に限定されるものではなく、四角形状や三角形状等の多角形状であってもよいし、スリット形状であってもよい。貫通孔の形状がこのような形状である場合、貫通孔の径とは、孔面積が等価な円形状の孔の径のこととする。以降、表面多孔板２ａと内部多孔板２ｂとをあわせて多孔板２ということがある。なお、内部多孔板２ｂの数は１枚に限定されず、２枚以上であってもよい。 The surface perforated plate 2a and the inner perforated plate 2b are made of metal such as aluminum and have a large number of circular through holes. In addition, the shape of the through hole is not limited to a circle, and may be a polygonal shape such as a square shape or a triangular shape, or may be a slit shape. When the shape of the through hole is such a shape, the diameter of the through hole is a diameter of a circular hole having an equivalent hole area. Hereinafter, the surface porous plate 2a and the internal porous plate 2b may be collectively referred to as the porous plate 2. The number of internal porous plates 2b is not limited to one and may be two or more.
表面多孔板２ａの板厚、開口率及び貫通孔の孔径は、貫通孔を通過する空気に対して粘性を生じさせるように設定されている。例えば、表面多孔板２ａの板厚は０．８〜１．２ｍｍ程度であり、表面多孔板２ａの開口率は８％以下であり、表面多孔板２ａの貫通孔の孔径は０．８〜１．５ｍｍ程度である。同様に、内部多孔板２ｂの板厚、開口率及び貫通孔の孔径は、貫通孔を通過する空気に対して粘性を生じさせるように設定されている。例えば、内部多孔板２ｂの板厚は０．３ｍｍ程度であり、内部多孔板２ｂの開口率は０．５％程度であり、内部多孔板２ｂの貫通孔の孔径は０．５ｍｍ程度である。なお、上記の板厚、開口率及び貫通孔の孔径は、例示であって、これに限定されない。表面多孔板２ａは、板厚が０．３〜２．０ｍｍ、貫通孔の孔径が０．５〜２．０ｍｍ、開口率が１０％であってもよい。 The plate thickness, the aperture ratio, and the hole diameter of the through hole of the surface porous plate 2a are set so as to cause viscosity to the air passing through the through hole. For example, the thickness of the surface porous plate 2a is about 0.8 to 1.2 mm, the aperture ratio of the surface porous plate 2a is 8% or less, and the diameter of the through hole of the surface porous plate 2a is 0.8 to 1. About 5 mm. Similarly, the plate thickness, the aperture ratio, and the diameter of the through hole of the internal porous plate 2b are set so as to generate viscosity for the air passing through the through hole. For example, the thickness of the internal porous plate 2b is about 0.3 mm, the opening ratio of the internal porous plate 2b is about 0.5%, and the hole diameter of the through hole of the internal porous plate 2b is about 0.5 mm. In addition, said board thickness, an aperture ratio, and the hole diameter of a through-hole are illustrations, Comprising: It is not limited to this. The surface porous plate 2a may have a plate thickness of 0.3 to 2.0 mm, a through-hole diameter of 0.5 to 2.0 mm, and an aperture ratio of 10%.
背面板３は、鉄やステンレス等の金属製または樹脂製であって、多孔板２（表面多孔板２ａ、内部多孔板２ｂ）との間に所定の間隔をあけて多孔板２に対向配置されている。枠体４は、鉄やステンレス等の金属製または樹脂製であって、表面多孔板２ａと背面板３とで挟まれた空間を囲繞している。これにより、表面多孔板２ａと内部多孔板２ｂとの間には、第１空気層６ａが形成されているとともに、内部多孔板２ｂと背面板３との間には、第２空気層６ｂが形成されている。多孔板２の面に直交する方向において、第１空気層６ａの厚み、および、第２空気層６ｂの厚みは、例えば３０ｍｍである。なお、第１空気層６ａの厚みと第２空気層６ｂの厚みとは異なっていてもよい。以降、第１空気層６ａと第２空気層６ｂとをあわせて空気層６ということがある。 The back plate 3 is made of metal such as iron or stainless steel or resin, and is disposed to face the perforated plate 2 with a predetermined interval between the perforated plate 2 (surface perforated plate 2a, internal perforated plate 2b). ing. The frame body 4 is made of metal such as iron or stainless steel or resin, and surrounds a space sandwiched between the front porous plate 2 a and the back plate 3. Thus, a first air layer 6a is formed between the surface porous plate 2a and the inner porous plate 2b, and a second air layer 6b is formed between the inner porous plate 2b and the back plate 3. Is formed. In the direction orthogonal to the surface of the porous plate 2, the thickness of the first air layer 6a and the thickness of the second air layer 6b are, for example, 30 mm. The thickness of the first air layer 6a may be different from the thickness of the second air layer 6b. Hereinafter, the first air layer 6a and the second air layer 6b may be collectively referred to as the air layer 6.
補強リブ５は、金属製または樹脂製であって、吸音パネル１の短辺と同等の長さを有しており、表面多孔板２ａの背面板３側の面、および、内部多孔板２ｂの背面板３側の面に、吸音パネル１の短辺に平行となるように取り付けられている。また、補強リブ５は、吸音パネル１の長辺に沿って所定の間隔でそれぞれ４つずつ取り付けられている。なお、補強リブ５の数はこれに限定されない。これにより、表面多孔板２ａの背面板３側の面および内部多孔板２ｂの背面板３側の面は、それぞれ５つに分割されている。以降、複数の補強リブ５で多孔板２の背面板３側の面が分割されている数を多孔板面分割数という。なお、表面多孔板２ａに設けられた補強リブ５と、内部多孔板２ｂに設けられた補強リブ５とで、隣り合う補強リブ５同士の間隔、補強リブ５の本数、補強リブ５の幅Ｂ等が同じであってもよいし、異なっていてもよい。 The reinforcing rib 5 is made of metal or resin and has a length equivalent to the short side of the sound absorbing panel 1, and the surface of the front porous plate 2a on the back plate 3 side and the inner porous plate 2b. It is attached to the surface on the back plate 3 side so as to be parallel to the short side of the sound absorbing panel 1. Further, four reinforcing ribs 5 are attached at predetermined intervals along the long side of the sound absorbing panel 1. The number of reinforcing ribs 5 is not limited to this. Thereby, the surface on the back plate 3 side of the surface porous plate 2a and the surface on the back plate 3 side of the internal porous plate 2b are each divided into five. Hereinafter, the number in which the surface on the back plate 3 side of the porous plate 2 is divided by the plurality of reinforcing ribs 5 is referred to as the number of divided porous plate surfaces. The reinforcing ribs 5 provided on the surface perforated plate 2a and the reinforcing ribs 5 provided on the inner perforated plate 2b include the distance between adjacent reinforcing ribs 5, the number of reinforcing ribs 5, and the width B of the reinforcing rib 5. Etc. may be the same or different.
このような構成において、音波が多孔板２（表面多孔板２ａ、内部多孔板２ｂ）の貫通孔を通過する際に、貫通孔の内壁面との摩擦によって音波エネルギーの一部が熱エネルギーに変換される。これにより、騒音が吸音される。つまり、騒音は、表面多孔板２ａの貫通孔を通過する際と、内部多孔板２ｂの貫通孔を通過する際に、それぞれ吸音される。 In such a configuration, when sound waves pass through the through holes of the porous plate 2 (surface porous plate 2a, internal porous plate 2b), part of the sound wave energy is converted into thermal energy by friction with the inner wall surface of the through holes. Is done. Thereby, noise is absorbed. That is, noise is absorbed when passing through the through hole of the surface porous plate 2a and when passing through the through hole of the internal porous plate 2b.
ここで、図１Ａに示すように、隣り合う補強リブ５間の距離をａとしたときに、隣り合う補強リブ５間の距離ａと、多孔板２（表面多孔板２ａ、内部多孔板２ｂ）の板厚ｔとを、以下の式（１）を満足するように設計する。 Here, as shown in FIG. 1A, when the distance between the adjacent reinforcing ribs 5 is a, the distance a between the adjacent reinforcing ribs 5 and the porous plate 2 (surface porous plate 2a, internal porous plate 2b). Is designed so as to satisfy the following expression (1).
ａ／ｔ＜Ｋ１×（Ａ／ｐ０）1/2 ・・・式（１）
ここで、Ａは多孔板２の許容応力、ｐ０は設計荷重（多孔板２に作用する設計上の荷重）、Ｋ１＝０．９３である。なお、係数Ｋ１は、境界条件による係数Ｋ１ａと、設計上の安全係数Ｋ１ｂとを掛け合わせた値として定義される。
a / t <K1 × (A / p0) 1/2 Formula (1)
Here, A is the allowable stress of the perforated plate 2, p0 is the design load (design load acting on the perforated plate 2), and K1 = 0.93. The coefficient K1 is defined as a value obtained by multiplying the coefficient K1a by the boundary condition and the design safety coefficient K1b.
上記の式（１）は、多孔板２を両端が支持された１次元のはりとみなしたときに、このはりに列車風圧を模擬した等分布荷重が掛かった際に最大曲げモーメントを受けるはり中央部における応力値と、多孔板２の材料の耐力から決まる許容応力との関係を表している。はり中央部における応力値は理論値であり、その計算式は、はりの両端の支持条件ごとに一般的に開示されている。つまり、はり中央部における応力値は、はりの両端の支持条件によって変わる。両端単純支持の場合、境界条件による係数Ｋ１ａ＝１．１５となる。ここで、両端単純支持とは、はりの一方の端が支持台座に固定され、他方の端が支持台座に自由支持された状態をいう。また、両端固定支持の場合、境界条件による係数Ｋ１ａ＝１．４１となる。ここで、両端固定支持とは、はりの両端がそれぞれ支持台座に固定された状態をいう。そして、はりの両端の支持条件としては、上記の２種類が両極端な条件となる。そのため、実構造では、境界条件による係数Ｋ１ａは必ず上記の２つの値の間の値となる。 The above equation (1) indicates that when the perforated plate 2 is regarded as a one-dimensional beam supported at both ends, the center of the beam that receives the maximum bending moment when an evenly distributed load is applied to this beam simulating train wind pressure. This represents the relationship between the stress value at the portion and the allowable stress determined from the proof stress of the material of the porous plate 2. The stress value at the center of the beam is a theoretical value, and the calculation formula is generally disclosed for each support condition at both ends of the beam. That is, the stress value at the center of the beam varies depending on the support conditions at both ends of the beam. In the case of simple support at both ends, the coefficient K1a = 1.15 due to the boundary condition. Here, the both-end simple support means a state in which one end of the beam is fixed to the support base and the other end is freely supported by the support base. Further, in the case of both-end fixed support, the coefficient K1a = 1.41 due to the boundary condition. Here, the both-end fixed support means a state in which both ends of the beam are respectively fixed to the support base. As the support conditions for both ends of the beam, the above two types are extreme conditions. Therefore, in the actual structure, the coefficient K1a due to the boundary condition is always a value between the above two values.
また、多孔板の許容応力Ａの値を計算するための式は、例えば「鉄道構造物等設計標準・同解説」などに示されており、安全係数を見込んだ計算式となっている。安全係数には、荷重係数、構造解析係数、材料係数、部材係数、構造物係数などがある。トータルの安全係数は、設計荷重ｐ０を列車風圧による最大圧力値（終局限界状態）とするか、運行状態での変動圧力値（使用限界状態）とするかによって異なる。ここで、終局限界状態とは、台風などの異常状態であり、使用限界状態とは、列車が通常走行している状態である。設計荷重ｐ０を最大圧力値とする場合、設計上の安全係数Ｋ１ｂ＝０．８１となる。また、設計荷重ｐ０を変動圧力値とする場合、設計上の安全係数Ｋ１ｂ＝１．０となる。 Moreover, the formula for calculating the value of the permissible stress A of the perforated plate is shown in, for example, “Railway structure design standard / explanation”, etc., and is a calculation formula considering a safety factor. The safety coefficient includes a load coefficient, a structure analysis coefficient, a material coefficient, a member coefficient, a structure coefficient, and the like. The total safety factor differs depending on whether the design load p0 is the maximum pressure value (final limit state) due to the train wind pressure or the fluctuating pressure value in the operating state (usage limit state). Here, the ultimate limit state is an abnormal state such as a typhoon, and the use limit state is a state where the train is normally running. When the design load p0 is the maximum pressure value, the design safety coefficient K1b = 0.81. When the design load p0 is a variable pressure value, the design safety factor K1b = 1.0.
よって、境界条件による係数Ｋ１ａと設計上の安全係数Ｋ１ｂとを掛け合わせた値であるＫ１は、０．９３〜１．４１となるが、最小値である０．９３の場合に式（１）を満たせば、設計荷重ｐ０に対して多孔板２の許容応力Ａを満たすことができる。なお、多孔板２の許容応力Ａは、多孔部（貫通孔が設けられている部分）への応力集中を考慮すると、貫通孔が設けられていない材料そのものの許容応力の１／３になる。 Therefore, K1 which is a value obtained by multiplying the coefficient K1a by the boundary condition and the design safety coefficient K1b is 0.93 to 1.41, but in the case of 0.93 which is the minimum value, the expression (1) Can be satisfied, the permissible stress A of the porous plate 2 can be satisfied with respect to the design load p0. Note that the allowable stress A of the perforated plate 2 is 1/3 of the allowable stress of the material itself in which the through hole is not provided in consideration of the stress concentration on the porous portion (the portion where the through hole is provided).
このように、式（１）を満足することで、高速鉄道車両の通過時の列車風圧などに耐えることができるように、吸音パネル１の耐力を向上させることができる。 Thus, by satisfying the formula (1), the proof stress of the sound absorbing panel 1 can be improved so as to be able to withstand the train wind pressure when the high-speed railway vehicle passes.
しかし、多孔板２に複数の補強リブ５を取り付けると、貫通孔の一部が補強リブ５で塞がれることで吸音面積が減少するので、補強リブ５を設けずに多孔板２と空気層６のみの系で吸音設計した場合の多孔板２の設計開口率αのままでは、吸音パネル１の吸音性能が低下する。 However, if a plurality of reinforcing ribs 5 are attached to the perforated plate 2, the sound absorption area is reduced by partially closing the through holes with the reinforcing ribs 5. If the design aperture ratio α of the perforated plate 2 when the sound absorption design is performed with only 6 systems, the sound absorption performance of the sound absorption panel 1 is deteriorated.
そこで、多孔板２（表面多孔板２ａ、内部多孔板２ｂ）の開口率βを、以下の式（２）を満足するように設計する。 Therefore, the aperture ratio β of the perforated plate 2 (surface perforated plate 2a, inner perforated plate 2b) is designed to satisfy the following formula (2).
β＝（Ｂ（１−１／Ｎ）／ａ＋１）×α×Ｋ２ ・・・式（２）
ここで、Ｂは補強リブ５の幅（図１Ａ参照）、Ｎは多孔板面分割数（補強リブ５により多孔板２の面が分割された数）、αは補強リブ５を設けずに吸音設計した場合の多孔板２の設計開口率、Ｋ２は０．８以上１．４以下の値をとる係数である。
β = (B (1-1 / N) / a + 1) × α × K2 Formula (2)
Here, B is the width of the reinforcing rib 5 (see FIG. 1A), N is the number of perforated plate surfaces (the number of the surface of the perforated plate 2 divided by the reinforcing ribs 5), and α is the sound absorption without providing the reinforcing ribs 5. The designed aperture ratio K2 of the porous plate 2 when designed is a coefficient that takes a value of 0.8 or more and 1.4 or less.
上記の式（２）は、補強リブ５が取り付けられた部分の面積も含んだ多孔板２の全面積と、補強リブ５が取り付けられた部分の面積を除いた多孔板２の面積との面積比から、吸音性能を元の設計値とほぼ同等に保持するように、開口率を計算したものである。 The above formula (2) is the area between the total area of the porous plate 2 including the area of the portion to which the reinforcing rib 5 is attached and the area of the porous plate 2 excluding the area of the portion to which the reinforcing rib 5 is attached. From the ratio, the aperture ratio is calculated so that the sound absorption performance is maintained substantially equal to the original design value.
ここで、Ｋ２＝１．０の場合、吸音性能は元の設計値と等しくなる。そして、Ｋ２＝０．８〜１．４の範囲では、吸音性能は元の設計値とほぼ同等になる。これにより、多孔板２に補強リブ５を取り付けた場合であっても、吸音パネル１の吸音性能を維持することができる。 Here, when K2 = 1.0, the sound absorption performance is equal to the original design value. In the range of K2 = 0.8 to 1.4, the sound absorption performance is almost equal to the original design value. Thereby, even if it is a case where the reinforcement rib 5 is attached to the perforated panel 2, the sound absorption performance of the sound absorption panel 1 can be maintained.
なお、吸音パネル１の短辺に平行な補強リブ５とは別に、吸音パネル１の長辺に平行な補強リブを設けてもよい。このような補強リブを設けた場合であっても、式（１）および式（２）を満足するようにすることで、吸音パネル１の耐力を向上させながら、吸音パネル１の吸音性能を維持することができる。 In addition to the reinforcing ribs 5 parallel to the short sides of the sound absorbing panel 1, reinforcing ribs parallel to the long sides of the sound absorbing panel 1 may be provided. Even when such a reinforcing rib is provided, the sound absorbing performance of the sound absorbing panel 1 is maintained while improving the proof stress of the sound absorbing panel 1 by satisfying the expressions (1) and (2). can do.
（吸音性能評価）
次に、吸音パネル１の吸音性能を評価した。補強リブ５を設けずに吸音設計した場合の表面多孔板２ａの設計開口率αを３％とし、Ｋ２の値を１．０、０．８（下限値）、１．４（上限値）、０．７５（下限値の下）、１．４５（上限値の上）の５種類に異ならせることで、表面多孔板２ａの開口率βを３％、２．４％、４．２％、２．２５％、４．３５％の５種類に異ならせた。表面多孔板２ａの計算条件（仕様）を表１に示す。また、第１空気層６ａおよび第２空気層６ｂの厚み（多孔板２の面に直交する方向の厚み）をそれぞれ３０ｍｍ、内部多孔板２ｂの板厚を０．３ｍｍ、内部多孔板２ｂの開口率を０．５％、内部多孔板２ｂの孔径を０．５ｍｍとした。
(Sound absorption performance evaluation)
Next, the sound absorbing performance of the sound absorbing panel 1 was evaluated. The design aperture ratio α of the surface porous plate 2a in the case of sound absorption design without providing the reinforcing rib 5 is 3%, and the values of K2 are 1.0, 0.8 (lower limit), 1.4 (upper limit), By differentiating into 5 types of 0.75 (below the lower limit) and 1.45 (above the upper limit), the aperture ratio β of the surface porous plate 2a is 3%, 2.4%, 4.2%, The difference was 5.25% and 4.35%. Table 1 shows the calculation conditions (specifications) of the surface porous plate 2a. The thickness of the first air layer 6a and the second air layer 6b (thickness in the direction perpendicular to the surface of the porous plate 2) is 30 mm, the thickness of the internal porous plate 2b is 0.3 mm, and the opening of the internal porous plate 2b The rate was 0.5%, and the pore diameter of the internal porous plate 2b was 0.5 mm.
各周波数帯域における吸音率を図２に示す。Ｋ２＝１．０である凡例（１）が、吸音設計による設計値と等しい吸音性能であるが、Ｋ２＝０．８である凡例（２）や、Ｋ２＝１．４である凡例（３）においても、設計値に近い吸音性能となっていることがわかる。 The sound absorption rate in each frequency band is shown in FIG. The legend (1) where K2 = 1.0 has the same sound absorption performance as the design value by the sound absorption design, but the legend (2) where K2 = 0.8 and the legend (3) where K2 = 1.4. It can also be seen that the sound absorption performance is close to the design value.
各周波数帯域における吸音率比率を図３に示す。吸音率比率は、吸音率を設計目標の吸音率（設計吸音率）で除した値を１から引いた値であり、設計吸音率に対する吸音率のずれ量を示している。この吸音率比率が０％であると、ずれ量が０で設計吸音率に一致する。凡例（１）の吸音率は設計目標値なので、吸音率比率は０％となっているが、凡例（２）、凡例（３）においても、吸音率比率は２０％を下回っている。ここで、例えば、設計吸音率が０．９２程度の場合、吸音率比率が２０％異なると、騒音が吸音パネル１に当たってはね返る１回の反射につき５ｄＢ程度、音の低減量が小さくなる。このことから、吸音率比率２０％以内を設計上好適な範囲として考えることとする。そうすると、凡例（２）、凡例（３）の吸音率比率が２０％を下回ることで、凡例（２）、凡例（３）の吸音率が設計吸音率とほぼ同等になっていることがわかる。 The sound absorption ratio in each frequency band is shown in FIG. The sound absorption rate ratio is a value obtained by subtracting a value obtained by dividing the sound absorption rate by the design target sound absorption rate (design sound absorption rate) from 1, and indicates the amount of deviation of the sound absorption rate from the design sound absorption rate. If this sound absorption ratio is 0%, the deviation amount is 0, which matches the design sound absorption coefficient. Since the sound absorption rate of the legend (1) is a design target value, the sound absorption rate ratio is 0%. In the legend (2) and the legend (3), the sound absorption rate ratio is lower than 20%. Here, for example, in the case where the designed sound absorption coefficient is about 0.92, if the sound absorption ratio is different by 20%, the amount of sound reduction is reduced by about 5 dB for each reflection of noise that bounces off the sound absorption panel 1. For this reason, a sound absorption ratio within 20% is considered as a suitable range for design. Then, it can be understood that the sound absorption ratios of the legend (2) and the legend (3) are almost equal to the designed sound absorption coefficient because the sound absorption ratio of the legend (2) and the legend (3) is less than 20%.
なお、Ｋ２の値が０．８〜１．４の範囲内である凡例（２）および凡例（３）では、吸音率比率が２０％未満となっているのに対し、Ｋ２の値が０．８〜１．４の範囲外である凡例（４）および凡例（５）では、吸音率比率が２０％を超えている帯域があることがわかる。よって、特にＫ２の値が０．８〜１．４の範囲では、吸音性能は元の設計値に近い値となることがわかる。 In the legend (2) and the legend (3) where the value of K2 is in the range of 0.8 to 1.4, the sound absorption ratio is less than 20%, whereas the value of K2 is 0. In the legend (4) and the legend (5) which are out of the range of 8 to 1.4, it can be seen that there is a band where the sound absorption ratio is over 20%. Therefore, it can be seen that the sound absorption performance is close to the original design value, particularly when the value of K2 is in the range of 0.8 to 1.4.
（効果）
以上に述べたように、本実施形態に係る吸音パネル１によると、隣り合う補強リブ５間の距離ａと、多孔板２の板厚ｔとが上記の式（１）を満足している。これにより、高速鉄道車両の通過時の列車風圧などに耐えることができるように、吸音パネル１の耐力を向上させることができる。また、多孔板２の開口率βが上記の式（２）を満足している。これにより、多孔板２に補強リブ５を取り付けた場合であっても、吸音パネル１の吸音性能を維持することができる。
(effect)
As described above, according to the sound absorbing panel 1 according to the present embodiment, the distance a between the adjacent reinforcing ribs 5 and the plate thickness t of the perforated plate 2 satisfy the above formula (1). Thereby, the proof stress of the sound absorption panel 1 can be improved so that it can endure the train wind pressure etc. at the time of passage of a high-speed rail vehicle. Further, the aperture ratio β of the perforated plate 2 satisfies the above formula (2). Thereby, even if it is a case where the reinforcement rib 5 is attached to the perforated panel 2, the sound absorption performance of the sound absorption panel 1 can be maintained.
また、Ｋ２の値を０．８以上１．４以下にすることで、吸音パネル１の吸音性能を元の設計値とほぼ同等にすることができる。これにより、吸音パネル１の吸音性能を好適に維持することができる。 Further, by setting the value of K2 between 0.8 and 1.4, the sound absorbing performance of the sound absorbing panel 1 can be made substantially equal to the original design value. Thereby, the sound absorption performance of the sound absorbing panel 1 can be suitably maintained.
［第２実施形態］
（吸音パネルの構成）
次に、本発明の第２実施形態に係る吸音パネル２０１について説明する。なお、上述した構成要素と同じ構成要素については、同じ参照番号を付してその説明を省略する。本実施形態の吸音パネル２０１が第１実施形態の吸音パネル１と異なる点は、表面多孔板２ａおよび内部多孔板２ｂの少なくとも一方の板厚ｔを、補強リブ５を設けずに吸音設計した場合の多孔板２の設計板厚ｔ’よりも厚くしているとともに、板厚ｔ’である多孔板２（表面多孔板２ａ、内部多孔板２ｂ）に補強リブ５を設けた場合の多孔板２の開口率β’が以下の式（３）を満足し、且つ、板厚ｔである多孔板２の開口率γが以下の式（４）を満足している点である。
[Second Embodiment]
(Configuration of sound absorbing panel)
Next, a sound absorbing panel 201 according to the second embodiment of the present invention will be described. In addition, about the same component as the component mentioned above, the same reference number is attached | subjected and the description is abbreviate | omitted. The sound absorbing panel 201 of the present embodiment is different from the sound absorbing panel 1 of the first embodiment in that at least one plate thickness t of the surface porous plate 2a and the inner porous plate 2b is designed to absorb sound without providing the reinforcing rib 5. The perforated plate 2 when the reinforcing rib 5 is provided on the perforated plate 2 (surface perforated plate 2a, inner perforated plate 2b) having the plate thickness t '. The aperture ratio β ′ of the above satisfies the following formula (3), and the aperture ratio γ of the porous plate 2 having the plate thickness t satisfies the following formula (4).
β’＝（Ｂ（１−１／Ｎ）／ａ＋１）×α×１ ・・・式（３）
γ＝ｔ／ｔ’×β’×Ｋ３ ・・・式（４）
ここで、Ｂは補強リブ５の幅、Ｎは多孔板面分割数（補強リブ５により多孔板２の面が分割された数）、αは補強リブ５を設けずに吸音設計した場合の多孔板２の設計開口率、ｔ’は補強リブ５を設けずに吸音設計した場合の多孔板２の設計板厚、Ｋ３は０．８５以上１．１５以下の値をとる係数であって、ｔ’＜ｔである。なお、式（３）は、式（２）において、「Ｋ２＝１」として開口率β’を算出するものであり、補強リブ５を設けない場合は、「Ｎ＝１」として開口率β’を算出すればよい。
β ′ = (B (1-1 / N) / a + 1) × α × 1 Formula (3)
γ = t / t ′ × β ′ × K3 (4)
Here, B is the width of the reinforcing rib 5, N is the number of perforated plate surfaces (the number of the surface of the perforated plate 2 divided by the reinforcing rib 5), and α is the porosity when the sound absorbing design is performed without the reinforcing rib 5. The design aperture ratio of the plate 2, t ′ is the design plate thickness of the porous plate 2 when sound absorption design is performed without providing the reinforcing rib 5, and K3 is a coefficient that takes a value of 0.85 or more and 1.15 or less, t '<T. The expression (3) is for calculating the aperture ratio β ′ as “K2 = 1” in the expression (2). When the reinforcing rib 5 is not provided, the aperture ratio β ′ is determined as “N = 1”. May be calculated.
吸音パネル２０１の耐力を向上させるには、多孔板２の板厚を厚くすればよい。しかし、設計板厚ｔ’で吸音設計を実施し、設計開口率αまたは設計板厚ｔ’における開口率β’で吸音性能を満たしている場合、即ち、式（３）を満足している場合、多孔板２の板厚をｔ’からｔに厚くすると、貫通孔を空気が通りにくくなるため、設計開口率αまたは設計板厚ｔ’における開口率β’のままでは吸音性能が低下する。 In order to improve the yield strength of the sound absorbing panel 201, the thickness of the porous plate 2 may be increased. However, when the sound absorption design is performed with the design thickness t ′ and the sound absorption performance is satisfied with the design aperture ratio α or the aperture ratio β ′ at the design thickness t ′, that is, when the expression (3) is satisfied. If the plate thickness of the porous plate 2 is increased from t ′ to t, it becomes difficult for air to pass through the through hole. Therefore, the sound absorption performance is lowered if the design aperture ratio α or the aperture ratio β ′ at the design plate thickness t ′ remains unchanged.
そこで、多孔板２（表面多孔板２ａ、内部多孔板２ｂ）の開口率γを、上記の式（４）を満足するように設計する。ここで、Ｋ３＝１．０の場合、吸音性能は元の設計値とほぼ同じになる。そして、Ｋ３＝０．８５〜１．１５の範囲では、吸音性能は元の設計値に近い値となる。これにより、多孔板２に補強リブ５を取り付け、さらに多孔板２の板厚を厚くした場合であっても、吸音パネル２０１の吸音性能を維持することができる。 Therefore, the aperture ratio γ of the perforated plate 2 (surface perforated plate 2a, inner perforated plate 2b) is designed so as to satisfy the above formula (4). Here, when K3 = 1.0, the sound absorption performance is substantially the same as the original design value. In the range of K3 = 0.85 to 1.15, the sound absorption performance is close to the original design value. Thereby, even if the reinforcing rib 5 is attached to the porous plate 2 and the plate thickness of the porous plate 2 is increased, the sound absorbing performance of the sound absorbing panel 201 can be maintained.
なお、吸音パネル２０１の短辺に平行な補強リブ５とは別に、吸音パネル２０１の長辺に平行な補強リブを設けてもよい。このような補強リブを設けた場合であっても、式（１）、式（３）および式（４）を満足するようにすることで、吸音パネル２０１の耐力を向上させながら、吸音パネル２０１の吸音性能を維持することができる。 In addition to the reinforcing ribs 5 parallel to the short sides of the sound absorbing panel 201, reinforcing ribs parallel to the long sides of the sound absorbing panel 201 may be provided. Even when such a reinforcing rib is provided, the sound absorbing panel 201 is improved while the proof stress of the sound absorbing panel 201 is improved by satisfying the expressions (1), (3), and (4). The sound absorption performance can be maintained.
（吸音性能評価）
次に、吸音パネル２０１の吸音性能を評価した。補強リブ５を設けずに吸音設計した場合の表面多孔板２ａの設計開口率αを３％とし、補強リブ５を設けずに吸音設計した場合の表面多孔板２ａの設計板厚ｔ’を０．８ｍｍとした。そして、設計開口率α且つ設計板厚ｔ’である、吸音性能が設計目標値（設計吸音率）のものと、これに対して、表面多孔板２ａの板厚ｔを１．２ｍｍに厚くして、Ｋ３の値を０．６７（開口率３％のまま）、１．０、０．８５（下限値）、１．１５（上限値）、０．８（下限値の下）、１．２（上限値の上）の６種類に異ならせたものとを用いて評価を行った。表面多孔板２ａの計算条件（仕様）を表２に示す。また、第１空気層６ａおよび第２空気層６ｂの厚み（多孔板２の面に直交する方向の厚み）をそれぞれ３０ｍｍ、内部多孔板２ｂの板厚を０．３ｍｍ、内部多孔板２ｂの開口率を０．８％、内部多孔板２ｂの孔径を０．５ｍｍとした。
(Sound absorption performance evaluation)
Next, the sound absorbing performance of the sound absorbing panel 201 was evaluated. The design aperture ratio α of the surface perforated plate 2a when the sound absorbing design is performed without providing the reinforcing rib 5 is 3%, and the design thickness t ′ of the surface perforated plate 2a when the sound absorbing design is performed without providing the reinforcing rib 5 is 0. 8 mm. Then, the design aperture ratio α and the design plate thickness t ′, and the sound absorption performance of the design target value (design sound absorption rate), and the plate thickness t of the surface porous plate 2a are increased to 1.2 mm. The value of K3 is 0.67 (with an aperture ratio of 3%), 1.0, 0.85 (lower limit value), 1.15 (upper limit value), 0.8 (below the lower limit value), 1. Evaluation was performed using 6 different types (2 above the upper limit). Table 2 shows the calculation conditions (specifications) of the surface porous plate 2a. The thickness of the first air layer 6a and the second air layer 6b (thickness in the direction perpendicular to the surface of the porous plate 2) is 30 mm, the thickness of the internal porous plate 2b is 0.3 mm, and the opening of the internal porous plate 2b The rate was 0.8%, and the pore diameter of the internal porous plate 2b was 0.5 mm.
各周波数帯域における吸音率を図４に示す。また、各周波数帯域における吸音率比率を図５に示す。凡例（１）が、吸音設計による設計吸音率であるが、凡例（１）に対して表面多孔板２ａの板厚ｔを１．２ｍｍに厚くした凡例（２）では、吸音率が設計吸音率から大きくずれており、吸音率比率が２０％以上となっている帯域があることがわかる。よって、設計開口率α且つ設計板厚ｔ’で吸音性能を満たしているものに対して、設計開口率αを変えずに表面多孔板２ａの板厚をｔ’からｔに厚くすると、吸音性能が低下することがわかる。また、凡例（３）〜（５）では、吸音率比率は２０％を下回っており、吸音率が設計吸音率に近い値となっていることがわかる。特に、Ｋ３＝１．０である凡例（３）の場合、吸音率比率は１０％以下となっており、設計吸音率と同等の吸音率となっていることがわかる。 The sound absorption rate in each frequency band is shown in FIG. Further, the sound absorption ratio in each frequency band is shown in FIG. The legend (1) is the designed sound absorption coefficient by the sound absorption design. In the legend (2) in which the thickness t of the surface porous plate 2a is increased to 1.2 mm as compared with the legend (1), the sound absorption coefficient is the designed sound absorption coefficient. It can be seen that there is a band in which the sound absorption ratio is 20% or more. Therefore, when the thickness of the surface porous plate 2a is increased from t ′ to t without changing the design aperture ratio α, while the design aperture ratio α and the design plate thickness t ′ satisfy the sound absorption performance, the sound absorption performance. It turns out that falls. Further, in the legends (3) to (5), the sound absorption rate ratio is less than 20%, and it can be seen that the sound absorption rate is close to the designed sound absorption rate. In particular, in the case of the legend (3) in which K3 = 1.0, the sound absorption ratio is 10% or less, and it can be seen that the sound absorption coefficient is equal to the design sound absorption coefficient.
なお、Ｋ３の値が０．８５〜１．１５の範囲内である凡例（３）、凡例（４）および凡例（５）では、吸音率比率が２０％未満となっているのに対し、Ｋ３の値が０．８５〜１．１５の範囲外である凡例（２）、凡例（６）および凡例（７）では、吸音率比率が２０％を超えている帯域があることがわかる。よって、特にＫ３の値が０．８５〜１．１５の範囲では、吸音性能は元の設計値に近い値となることがわかる。 In the legend (3), legend (4), and legend (5) where the value of K3 is in the range of 0.85 to 1.15, the sound absorption ratio is less than 20%, whereas K3 In the legend (2), the legend (6), and the legend (7) whose values are outside the range of 0.85 to 1.15, it can be seen that there is a band in which the sound absorption rate ratio exceeds 20%. Therefore, it can be seen that the sound absorption performance is close to the original design value especially in the range of K3 from 0.85 to 1.15.
さらに、吸音パネル２０１の吸音性能を評価した。補強リブ５を設けずに吸音設計した場合の表面多孔板２ａの設計開口率αを５％とし、補強リブ５を設けずに吸音設計した場合の表面多孔板２ａの設計板厚ｔ’を０．８ｍｍとした。そして、設計開口率α且つ設計板厚ｔ’である、吸音性能が設計目標値のものと、吸音性能が設計目標値のものに対して、計算条件（仕様）を異ならせたものとを用いて評価を行った。表面多孔板２ａの計算条件（仕様）を表３に示す。また、第１空気層６ａおよび第２空気層６ｂの厚み（多孔板２の面に直交する方向の厚み）をそれぞれ３０ｍｍ、内部多孔板２ｂの板厚を０．３ｍｍ、内部多孔板２ｂの開口率を０．８％、内部多孔板２ｂの孔径を０．５ｍｍとした。 Furthermore, the sound absorbing performance of the sound absorbing panel 201 was evaluated. The design aperture ratio α of the surface perforated plate 2a when the sound absorbing design is performed without providing the reinforcing rib 5 is 5%, and the design plate thickness t ′ of the surface perforated plate 2a when the sound absorbing design is performed without providing the reinforcing rib 5 is 0. 8 mm. Then, the design aperture ratio α and the design plate thickness t ′, which have the sound absorption performance of the design target value, and those having the sound absorption performance of the design target value and different calculation conditions (specifications) are used. And evaluated. Table 3 shows the calculation conditions (specifications) of the surface porous plate 2a. The thickness of the first air layer 6a and the second air layer 6b (thickness in the direction perpendicular to the surface of the porous plate 2) is 30 mm, the thickness of the internal porous plate 2b is 0.3 mm, and the opening of the internal porous plate 2b The rate was 0.8%, and the pore diameter of the internal porous plate 2b was 0.5 mm.
１／３オクターブバンド中心周波数に対する吸音率を図６に示す。また、１／３オクターブバンド中心周波数に対する吸音率比率を図７に示す。凡例（１）が、吸音設計による設計吸音率である。Ｋ３の値が０．８５〜１．１５の範囲内である凡例（４）および凡例（５）では、吸音率比率が２０％未満となっているのに対し、Ｋ３の値が０．８５〜１．１５の範囲外である凡例（２）および凡例（３）では、吸音率比率が２０％を超えている帯域があることがわかる。よって、Ｋ３の値が０．８５〜１．１５の範囲では、吸音性能は元の設計値に近い値となることがわかる。 FIG. 6 shows the sound absorption coefficient with respect to the center frequency of the 1/3 octave band. FIG. 7 shows the sound absorption ratio with respect to the center frequency of the 1/3 octave band. Legend (1) is the designed sound absorption coefficient by sound absorption design. In Legend (4) and Legend (5) where the value of K3 is in the range of 0.85 to 1.15, the sound absorption ratio is less than 20%, whereas the value of K3 is 0.85. In the legend (2) and the legend (3) which are outside the range of 1.15, it can be seen that there is a band where the sound absorption ratio is over 20%. Therefore, it can be seen that the sound absorption performance is close to the original design value when the value of K3 is in the range of 0.85 to 1.15.
（効果）
以上に述べたように、本実施形態に係る吸音パネル２０１によると、隣り合う補強リブ５間の距離ａと、多孔板２の板厚ｔとが上記の式（１）を満足している。これにより、高速鉄道車両の通過時の列車風圧などに耐えることができるように、吸音パネル２０１の耐力を向上させることができる。また、設計板厚ｔ’である多孔板２に補強リブ５を設けた場合の多孔板２の開口率β’が上記の式（３）を満足し、且つ、板厚ｔである多孔板２の開口率γが上記の式（４）を満足している。これにより、多孔板２に補強リブ５を取り付け、さらに多孔板２の板厚を厚くした場合であっても、吸音パネル２０１の吸音性能を維持することができる。
(effect)
As described above, according to the sound absorbing panel 201 according to the present embodiment, the distance a between the adjacent reinforcing ribs 5 and the plate thickness t of the perforated plate 2 satisfy the above formula (1). Thereby, the proof stress of the sound absorption panel 201 can be improved so that it can endure the train wind pressure etc. at the time of passage of a high-speed rail vehicle. Further, when the reinforcing rib 5 is provided on the porous plate 2 having the design plate thickness t ′, the aperture ratio β ′ of the porous plate 2 satisfies the above formula (3) and the porous plate 2 having the plate thickness t. The aperture ratio γ satisfies the above formula (4). Thereby, even if the reinforcing rib 5 is attached to the porous plate 2 and the plate thickness of the porous plate 2 is increased, the sound absorbing performance of the sound absorbing panel 201 can be maintained.
また、Ｋ３の値を０．８５以上１．１５以下にすることで、吸音パネル２０１の吸音性能を元の設計値に近い値にすることができる。これにより、吸音パネル２０１の吸音性能を好適に維持することができる。 Further, by setting the value of K3 between 0.85 and 1.15, the sound absorbing performance of the sound absorbing panel 201 can be made close to the original design value. Thereby, the sound absorption performance of the sound absorption panel 201 can be suitably maintained.
（本実施形態の変形例）
以上、本発明の実施形態を説明したが、具体例を例示したに過ぎず、特に本発明を限定するものではなく、具体的構成などは、適宜設計変更可能である。また、発明の実施の形態に記載された、作用及び効果は、本発明から生じる最も好適な作用及び効果を列挙したに過ぎず、本発明による作用及び効果は、本発明の実施の形態に記載されたものに限定されるものではない。
(Modification of this embodiment)
The embodiment of the present invention has been described above, but only specific examples are illustrated, and the present invention is not particularly limited, and the specific configuration and the like can be appropriately changed in design. Further, the actions and effects described in the embodiments of the invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to what was done.
１，２０１ 吸音パネル
２ 多孔板
２ａ 表面多孔板
２ｂ 内部多孔板
３ 背面板
４ 枠体
５ 補強リブ
６ 空気層
６ａ 第１空気層
６ｂ 第２空気層
1,201 Sound absorbing panel 2 Porous plate 2a Surface perforated plate 2b Internal perforated plate 3 Back plate 4 Frame body 5 Reinforcing rib 6 Air layer 6a First air layer 6b Second air layer
Claims (4)
多数の貫通孔を有する多孔板と、
前記多孔板との間に所定の間隔をあけて前記多孔板に対向配置された背面板と、
前記多孔板と前記背面板とで挟まれた空間を囲繞する枠体と、
前記多孔板の前記背面板側の面に所定の間隔で取り付けられた複数の補強リブと、
を有し、
隣り合う前記補強リブ間の距離ａと、前記多孔板の板厚ｔとが以下の式（１）を満足しているとともに、
前記多孔板の開口率βが以下の式（２）を満足していることを特徴とする吸音パネル。
ａ／ｔ＜Ｋ１×（Ａ／ｐ０）1/2 ・・・式（１）
β＝（Ｂ（１−１／Ｎ）／ａ＋１）×α×Ｋ２ ・・・式（２）
ここで、Ａは前記多孔板の許容応力、ｐ０は前記多孔板に作用する設計上の荷重、Ｋ１＝０．９３、Ｂは前記補強リブの幅、Ｎは前記補強リブにより前記多孔板の面が分割された数、αは前記補強リブを設けずに吸音設計した場合の前記多孔板の設計開口率、Ｋ２は係数である。 A sound absorbing panel for absorbing sound from a sound source,
A perforated plate having a large number of through holes;
A back plate disposed opposite to the perforated plate with a predetermined interval between the perforated plate;
A frame surrounding a space sandwiched between the porous plate and the back plate;
A plurality of reinforcing ribs attached to the surface on the back plate side of the porous plate at a predetermined interval;
Have
While the distance a between the adjacent reinforcing ribs and the thickness t of the perforated plate satisfy the following formula (1),
The sound absorbing panel, wherein the aperture ratio β of the porous plate satisfies the following formula (2).
a / t <K1 × (A / p0) 1/2 Formula (1)
β = (B (1-1 / N) / a + 1) × α × K2 Formula (2)
Here, A is an allowable stress of the porous plate, p0 is a design load acting on the porous plate, K1 = 0.93, B is a width of the reinforcing rib, and N is a surface of the porous plate by the reinforcing rib. Is the divided number, α is the design aperture ratio of the perforated plate in the case of sound absorption design without providing the reinforcing rib, and K2 is a coefficient.
多数の貫通孔を有する多孔板と、
前記多孔板との間に所定の間隔をあけて前記多孔板に対向配置された背面板と、
前記多孔板と前記背面板とで挟まれた空間を囲繞する枠体と、
前記多孔板の前記背面板側の面に所定の間隔で取り付けられた複数の補強リブと、
を有し、
隣り合う前記補強リブ間の距離ａと、前記多孔板の板厚ｔとが以下の式（１）を満足しているとともに、
板厚ｔ’である前記多孔板に前記補強リブを設けた場合の前記多孔板の開口率β’が以下の式（３）を満足し、且つ、板厚ｔである前記多孔板の開口率γが以下の式（４）を満足していることを特徴とする吸音パネル。
ａ／ｔ＜Ｋ１×（Ａ／ｐ０）1/2 ・・・式（１）
β’＝（Ｂ（１−１／Ｎ）／ａ＋１）×α×１ ・・・式（３）
γ＝ｔ／ｔ’×β’×Ｋ３ ・・・式（４）
ここで、Ａは前記多孔板の許容応力、ｐ０は前記多孔板に作用する設計上の荷重、Ｋ１＝０．９３、Ｂは前記補強リブの幅、Ｎは前記補強リブにより前記多孔板の面が分割された数、αは前記補強リブを設けずに吸音設計した場合の前記多孔板の設計開口率、ｔ’は前記補強リブを設けずに吸音設計した場合の前記多孔板の設計板厚、Ｋ３は係数であって、ｔ’＜ｔである。 A sound absorbing panel for absorbing sound from a sound source,
A perforated plate having a large number of through holes;
A back plate disposed opposite to the perforated plate with a predetermined interval between the perforated plate;
A frame surrounding a space sandwiched between the porous plate and the back plate;
A plurality of reinforcing ribs attached to the surface on the back plate side of the porous plate at a predetermined interval;
Have
While the distance a between the adjacent reinforcing ribs and the thickness t of the perforated plate satisfy the following formula (1),
When the reinforcing rib is provided on the porous plate having the plate thickness t ′, the aperture ratio β ′ of the porous plate satisfies the following formula (3), and the aperture ratio of the porous plate having the plate thickness t is A sound-absorbing panel characterized in that γ satisfies the following formula (4).
a / t <K1 × (A / p0) 1/2 Formula (1)
β ′ = (B (1-1 / N) / a + 1) × α × 1 Formula (3)
γ = t / t ′ × β ′ × K3 (4)
Here, A is an allowable stress of the porous plate, p0 is a design load acting on the porous plate, K1 = 0.93, B is a width of the reinforcing rib, and N is a surface of the porous plate by the reinforcing rib. , Α is the design aperture ratio of the porous plate when the sound absorption design is performed without providing the reinforcing rib, and t ′ is the design plate thickness of the porous plate when the sound absorption design is performed without providing the reinforcing rib. , K3 is a coefficient, and t ′ <t.
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| JP6495094B2 (en) * | 2015-05-19 | 2019-04-03 | 株式会社神戸製鋼所 | Perforated plate |
| JPWO2017038473A1 (en) | 2015-08-28 | 2018-06-14 | 天野エンザイム株式会社 | Endotoxin reducing thermolysin |
| JP6352336B2 (en) * | 2015-11-27 | 2018-07-04 | 株式会社神戸製鋼所 | Porous sound absorbing plate |
| JP6790978B2 (en) * | 2017-04-11 | 2020-11-25 | 株式会社デンソー | Blower |
| JPWO2019044589A1 (en) * | 2017-08-28 | 2020-08-06 | 富士フイルム株式会社 | Soundproof structure and soundproof structure |
| EP3690874A4 (en) * | 2017-09-25 | 2020-11-04 | FUJIFILM Corporation | Soundproofing structure |
| TWI752540B (en) * | 2020-06-30 | 2022-01-11 | 國立成功大學 | Sound absorption device |
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| JP4567513B2 (en) * | 2004-04-30 | 2010-10-20 | 株式会社神戸製鋼所 | Porous sound absorbing structure |
| JP2007058109A (en) * | 2005-08-26 | 2007-03-08 | Kobe Steel Ltd | Perforated board for sound absorption, sound absorbing board using the same, and method for manufacturing perforated board for sound absorption |
| JP2007100394A (en) * | 2005-10-04 | 2007-04-19 | Univ Of Yamanashi | Sound absorbing panel |
| JP5308006B2 (en) * | 2006-11-02 | 2013-10-09 | 株式会社神戸製鋼所 | Sound absorbing structure |
| JP5866172B2 (en) * | 2011-10-14 | 2016-02-17 | 株式会社神戸製鋼所 | Translucent sound absorbing panel |
| CN203007859U (en) * | 2012-12-31 | 2013-06-19 | 上海拓孚环保科技有限公司 | Acoustic board for mobile sound source |
| CN203320433U (en) * | 2013-07-04 | 2013-12-04 | 衡水中铁建环保工程有限公司 | Metallic sound barrier unit board for high speed railway |
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