Sound absorbing structure for anechoic chamber and anechoic chamber including the same

Patent metadata

Field	Value
Publication number	US-10510331-B2
Application number	US-201715590560-A
Country	US
Kind code	B2
Filing date	May 9, 2017
Priority date	Feb 17, 2017
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

This technology provides a sound absorbing structure comprising: an outer frame including an opening; a perforated plate member formed in the outer frame and including a rear surface facing the opening of the outer frame and a front surface opposite to the rear surface; and a rear sound absorber interposed between the rear surface of the perforated plate member and the opening of the outer frame, and an anechoic chamber comprising: a wall, a ceiling and a floor; and a plurality of sound absorbing structures of the embodiment fixed to at least the wall and the ceiling.

First claim

What is claimed is:

1. A sound absorbing structure comprising:
an outer frame including an opening;
a perforated plate member formed in the outer frame, including a metal plate and including a rear surface facing the opening of the outer frame and a front surface opposite to the rear surface; and
a rear sound absorber interposed between the rear surface of the perforated plate member and the opening of the outer frame,
wherein the perforated plate member has a fundamental resonance frequency (fp 0 ) of 125 Hz or less, which is calculated according to the following equations:

f

p
⁢

⁢
0

=

(

9
⁢

⁢
D
⁢

⁢

π
2

/
4

⁢
h
⁢

⁢

ρξ
4

)

⁢

ξ
2

⁢

L
x
2

+

3
⁢

ξ
2

⁢

L
y
2

+

2
⁢

ξ
2

+

2
⁢

ξ
2

⁡

(

1
-

σ
2

)

ξ
=

(

1
-
μ

)

⁢

L
a

⁢

L
b

⁢

L
x

⁢

L
y

π
⁢

⁢

r
2

,

wherein
D: Flexural rigidity of the perforated plate member,
h: Thickness of the perforated plate member,
ρ: Volume density of the perforated plate member,
σ: Poisson's ratio of the perforated plate member,
μ: Porosity (ratio of a total cross-sectional area of pores to a cross-sectional area of the perforated plate member),
r: Radius of pores,
L a : Horizontal pitch between pores,
L b : Vertical pitch between pores,
L x : Horizontal length of the perforated plate member, and
L y : Vertical length of the perforated plate member.

2. The sound absorbing structure of claim 1 , further comprising a front sound absorber interposed between the front surface of the perforated plate member and the outer frame.

3. The sound absorbing structure of claim 2 , wherein the front sound absorber comprises a porous sound absorber.

4. The sound absorbing structure of claim 3 , wherein the porous sound absorber comprises one or more selected from the group consisting of an inorganic fiber, an organic fiber, a chemical fiber, a foamed resin material and a sprayed fiber material.

5. The sound absorbing structure of claim 2 , wherein the front sound absorber has a thickness greater than 0 mm and up to 350 mm.

6. The sound absorbing structure of claim 1 , wherein the rear sound absorber comprises a porous sound absorber.

7. The sound absorbing structure of claim 6 , wherein the rear sound absorber comprises one or more selected from the group consisting of an inorganic fiber, an organic fiber, a chemical fiber, a foamed resin material and a sprayed fiber material.

8. The sound absorbing structure of claim 1 , wherein the rear sound absorber has a thickness of 50 to 250 mm.

9. The sound absorbing structure of claim 1 , wherein the perforated plate member has a ratio of a total area of pores to an area of the plate of 1 to 15%.

10. The sound absorbing structure of claim 1 , wherein the perforated plate member further comprises a cap for holding a pore height, wherein the cap for holding the pore height has a hollow shape and has a height which is equal to or greater than the pore height.

11. The sound absorbing structure of claim 1 , wherein the outer frame comprises a porous plate in which pores are formed in the plate.

12. The sound absorbing structure of claim 1 , wherein the outer frame has a ratio of a total area of pores to an area of the plate of 30 to 50%.

13. The sound absorbing structure of claim 1 , wherein the sound absorbing structure has a plate shape.

14. The sound absorbing structure of claim 1 , wherein the perforated plate member absorbs sound due to resonance caused by vibration of the plate and resonance caused by vibration of air inside pores.

15. An anechoic chamber comprising:
a wall, a cei

Assignees

• S I Pan
• Korea Res Inst Standards & Sci

Inventors

• Jeong Gab Cheol
• Ahn Eon Mo
• Park Jong Young
• Jung Sung Soo

Classifications

• E04B2001/8419

  Acoustical cones or the like, e.g. for anechoic chambers · CPC title

• B32B2266/0285

  Condensation resins of aldehydes, e.g. with phenols, ureas, melamines · CPC title

• B32B15/14

  next to a fibrous or filamentary layer · CPC title

• B32B2307/102

  Insulating · CPC title

• B32B21/10

  Next to a fibrous or filamentary layer · CPC title