2022 Fiscal Year Final Research Report
| Project/Area Number |
20K04367
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 20010:Mechanics and mechatronics-related
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| Research Institution | Kogakuin University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 均質化法 / 最適化 / 多孔質材 / 吸音材 / 吸音率 / 微視構造 |
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| Outline of Final Research Achievements |
Topology optimization based on a dynamic homogenization cannot be established as scheduled due to the convergence problem of the optimization although the sensitivity by the adjoint method is successfully obtained. We further continue to develop the method. However, we propose a new concept of a microscopic structure to enhance the sound absorption coefficient in the low frequency range below 1 kHz. In this concept, flow path in porous material where acoustic wave propagates is elongated. In this study, closed pores and open pores are aligned alternately and acoustic wave in normal incidence propagates at the angle of 45 degree. Sound absorption coefficient at 1 kHz reached to 0.5 for 10 mm thickness by designing the microscopic cell size of 400 micro meters. We also fabricate a proto type by using 3D printer BMF microArch S240 and verified the effect of the proposed new concept.
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| Free Research Field |
機械工学
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| Academic Significance and Societal Importance of the Research Achievements |
吸音という現象は，音波が微細な流路を伝播するときに発生する音響エネルギーの損失に起因するため，吸音材は連続気泡で構成されるのが通例であるが，その逆に独立気泡を混在させることで，向上させることが難しい低周波数帯域の吸音率を改善することができた．3Dプリンターで造形した多孔質材でその効果を実験的に検証することはできたが，実際の発泡系吸音材においてどのような化学的プロセスで実現できるかが課題である．今後，別の応用例を含めて情報発信することで当該分野の専門家との協調を図る．
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