US 2026/0260642 A1Published application

Method for designing causally optimal broadband acoustic metamaterial absorber, and absorber

AssigneeAcoustic Metamaterials LLC

InventorsMin YANG, Shuyu CHEN, Songwen XIAO, Yunfei XU

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Abstract

A method for designing and manufacturing a causally optimal broadband acoustic metamaterial absorber and an absorber. The method involves: (1) calculating a COBA spectrum by solving an optimization problem based on a causal constraint; (2) designing an array of resonators, the modal density and resonance strength of which match the COBA spectrum; and (3) using a mass production method, such as a molding process, to manufacture the absorber. As a result, compared with traditional porous absorbers, a produced acoustic metamaterial absorber shows a better broadband absorption performance under a given thickness constraint, particularly within a low frequency range. The present invention represents a significant advancement in the development of a high-performance and space-saving noise control solution.

Claims20

Dependent claims

A method for designing a causally optimal broadband acoustic metamaterial absorber, applied to an absorber with a given noise spectrum S(λ) and an effective thickness limit d, wherein λ is a wavelength of sound in air, and the method comprises:

(a) calculating a causally optimal broadband absorption (COBA) spectrum ACOBA(λ) by solving an optimization problem:
∫
0
∞
S
⁡
(
λ
)
⁢
A
⁡
(
λ
)
⁢
d
⁢
λ
is maximized based on a constraint condition equation
-
1
4
⁢
π
2
⁢
∫
0
∞
ln
[
1
-
A
⁡
(
λ
)
]
⁢
d
⁢
λ
≤
d
,
wherein S(λ) is a signal energy spectrum, and A(λ) is a material independent absorption spectrum;
and a solution is given based on ACOBA(λ)=1−μ/(4π2S(λ)) in a case where μ/(4π2S(λ))≤1, otherwise ACOBA(λ) equals 0, wherein μ is determined based on the constraint condition equation, ACOBA(λ) is the causally optimal broadband absorption spectrum, and μ is a Lagrange multiplier;
(b) designing an array of resonators, wherein a mode density (ω) of the array of the resonators and a resonance strength r(ω) of the array of the resonators match the COBA spectrum, and a relationship between the mode density and the resonance strength is determined based on the following equation:
𝒩
d
(
ω
)
⁢
r
⁡
(
ω
)
=
2
⁢
N
πφρ
⁢
c
⁢
A
C
⁢
O
⁢
B
⁢
A
(
ω
)
2
+
2
⁢
1
-
A
C
⁢
O
⁢
B
⁢
A
⁢
(
ω
)
-
A
C
⁢
O
⁢
B
⁢
A
(
ω
)
(
1
)
wherein ω is a circular frequency, φ is a surface porosity, ρ is an air density, and c is a sound speed;
and
(c) optimizing a structure of the array of the resonators in step (b) and constructing the array of the resonators into the causally optimal broadband acoustic metamaterial absorber.

113 more elements

Dependencies are inferred from the claim text.

Facts

Application: 19/154,513Filed 11 Apr 2024
Priority: 12 Feb 2023
Published: 3 Sep 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G10K 11/172
Methods or devices for protecting against, or for damping, noise or other acoustic waves in general: using resonance effects
G16C 60/00
Computational materials science, i.e. ict specially adapted for investigating the physical or
G06F 30/20
Computer-aided design [CAD]: design optimisation, verification or simulation
G10K 11/162
Methods or devices for protecting against, or for damping, noise or other acoustic waves in general: selection of materials