US 12,288,015 B2
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
Daiji Katsura, Hiroshima (JP); Keisuke Yamakawa, Hiroshima (JP); and Takashi Yamamoto, Tokyo (JP)
Assigned to MAZDA MOTOR CORPORATION, Hiroshima (JP); and KOGAKUIN UNIVERSITY, Tokyo (JP)
Filed by MAZDA MOTOR CORPORATION, Hiroshima (JP); and KOGAKUIN UNIVERSITY, Tokyo (JP)
Filed on Sep. 21, 2021, as Appl. No. 17/480,996.
Claims priority of application No. 2020-162078 (JP), filed on Sep. 28, 2020.
Prior Publication US 2022/0100934 A1, Mar. 31, 2022
Int. Cl. G06F 30/28 (2020.01); G01N 29/44 (2006.01); G10K 11/162 (2006.01); B60R 13/08 (2006.01); G06F 111/10 (2020.01)
CPC G06F 30/28 (2020.01) [G01N 29/4472 (2013.01); G10K 11/162 (2013.01); B60R 13/0838 (2013.01); G01N 2291/0289 (2013.01); G06F 2111/10 (2020.01)] 9 Claims
OG exemplary drawing
 
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:

OG Complex Work Unit Math
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, wf is a cell size, E0 is a Young's modulus of a material, and ν is a Poisson's ratio.