Method of designing internal structure of foamed resin sound absorbing material, device of designing the same, and method of calculating acoustic characteristics of foamed resin sound absorbing material

Patent metadata

Field	Value
Publication number	US-12288015-B2
Application number	US-202117480996-A
Country	US
Kind code	B2
Filing date	Sep 21, 2021
Priority date	Sep 28, 2020
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

A method of designing an internal structure of a foamed resin sound absorbing material includes: setting a microscopic structure model with a structure equivalent to the internal structure of the foamed resin sound absorbing material; calculating an acoustic characteristic by homogenization for each of a plurality of microscopic structure models, each being the microscopic structure model; identifying a relational expression between a Biot's parameter of the foamed resin sound absorbing material and the microscopic structure model; setting a target acoustic characteristic; identifying a Biot's parameter for achieving the target acoustic characteristic set, by Biot's modeling; and identifying a microscopic structure model corresponding to the Biot's parameter identified.

First claim

The invention claimed is:

1. A hybrid method of designing an internal structure of a foamed resin sound absorbing material, the method comprising:
setting a microscopic structure model with a periodic and homogeneous structure equivalent to the internal structure of the foamed resin sound absorbing material;
calculating a value of an acoustic characteristic by homogenization for each of a plurality of values for a parameter of the microscopic structure model, each of the plurality of values for the parameter of the microscopic structure model being sampled within a range of designing the foamed resin sound absorbing material;
identifying a relational expression between a Biot's parameter of the foamed resin sound absorbing material and the parameter of the microscopic structure model based on the values of the acoustic characteristic calculated;
setting a target acoustic characteristic that is a design target of the foamed resin sound absorbing material;
identifying a value of the Biot's parameter for achieving the target acoustic characteristic set, by Biot's modeling;
identifying, by a processor, a value of the parameter of the microscopic structure model corresponding to the value of the Biot's parameter identified to reduce calculation load of the designing target internal structure of the foamed resin sound absorbing material, using the relational expression; and
identifying the design of the target internal structure with the identified value of the parameter of the microscopic structure model corresponding to the value of the Biot's parameter identified, wherein the relational expression between the Biot's parameter and the parameter of the microscopic structure model includes:

α
∞

=

1
.
4

⁢
3

-

0
⁢
.43
⁢
φ

σ
=

3.88
×

10

-
3

⁢

w
f

-
2

⁡

(

1
-
φ

)

0.355

⁢

[

Pa
·
s

⁢

/

⁢

m
2

]

Λ
=

0
.
0

⁢
9
⁢
4
⁢

w
f

⁡

(

1
-
φ

)

-
0.359

⁢

[
m
]

Λ
′

=

0.38
⁢
3
⁢

w
f

⁡

(

1
-
φ

)

-
0.149

⁢

[
m
]

E
=

2
⁢

(

1
-
φ

)

2

3
⁢

(

1.9
-

0.9
⁢
φ

)

⁢

E
0

⁢

[
Pa
]

v
=

φ

2
⁢

(

2
-
φ

)

where α∞ is a tortuosity, Λ is a viscous characteristic length, φ is a porosity, Λ′ is a thermal characteristic length, σ is an airflow resistivity, E is an apparent Young's modulus, w f is a cell size, E 0 is a Young's modulus of a material, and ν is a Poisson's ratio.

2. The method o

Assignees

• Mazda Motor
• Univ Kogakuin

Inventors

• Katsura Daiji
• Yamakawa Keisuke
• Yamamoto Takashi

Classifications

• G10K11/162

  Selection of materials · CPC title

• G06F2111/10

  Numerical modelling · CPC title

• B60R13/0838

  for engine compartments · CPC title

• G01N2291/0289

  Internal structure, e.g. defects, grain size, texture · CPC title

• G01N29/4472

  Mathematical theories or simulation · CPC title