Optimizing broad-band passive absorbing structures for specified applications

Denis Siponen, Seppo Uosukainen, Ari Saarinen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

In buildings there are many noise sources which are needed to be attenuated one way or another. One of these noise sources is typically air shafts. These can be passively attenuated by using absorbers and resonators or their combinations. With right design, these absorbent and resonator structures can attenuate desired frequencies efficiently. To accomplish this, however, knowledge of acoustical phenomena behind these structures and use of computer algorithms which use this knowledge is required. Structures which consist of absorbers and resonators are examined. Here they are theoretically optimized by a computer algorithm which is based on defining a structure by the transmission line model. With this kind of relatively accurate model it is possible to avoid errors made by commonly used approximate formulas. Since absorbers, which contains perforated plate and absorbent have many variable parameters their acoustical efficiencies flexibly can be optimized by finding the most suitable parameters. Optimized and modeled absorbent structures have been constructed and their respective absorption coefficients have been measured. Measured values correspond well with estimated theoretical values. With measurements it is also confirmed that optimized resonator structures are noticeably more effective than normal nonoptimized resonator structures considering acoustic functioning. Measurements of absorption coefficient have been made with a impedance tube using the twochannel method with excitation being a logarithmic sinesweep.
Original languageEnglish
Title of host publicationEuronoise 2006 proceedings CD-ROM
PublisherAkustinen Seura ry
Number of pages6
Publication statusPublished - 2006
MoE publication typeNot Eligible
Event6th European Conference on Noise Control, Euronoise 2006 - Tampere, Finland
Duration: 30 May 20061 Jun 2006

Conference

Conference6th European Conference on Noise Control, Euronoise 2006
Abbreviated titleEuronoise
CountryFinland
CityTampere
Period30/05/061/06/06

Fingerprint

resonators
broadband
absorbents
absorbers
absorptivity
perforated plates
transmission lines
impedance
tubes
acoustics
air
excitation

Cite this

Siponen, D., Uosukainen, S., & Saarinen, A. (2006). Optimizing broad-band passive absorbing structures for specified applications. In Euronoise 2006 proceedings CD-ROM Akustinen Seura ry.
Siponen, Denis ; Uosukainen, Seppo ; Saarinen, Ari. / Optimizing broad-band passive absorbing structures for specified applications. Euronoise 2006 proceedings CD-ROM. Akustinen Seura ry, 2006.
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Siponen, D, Uosukainen, S & Saarinen, A 2006, Optimizing broad-band passive absorbing structures for specified applications. in Euronoise 2006 proceedings CD-ROM. Akustinen Seura ry, 6th European Conference on Noise Control, Euronoise 2006, Tampere, Finland, 30/05/06.

Optimizing broad-band passive absorbing structures for specified applications. / Siponen, Denis; Uosukainen, Seppo; Saarinen, Ari.

Euronoise 2006 proceedings CD-ROM. Akustinen Seura ry, 2006.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

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T1 - Optimizing broad-band passive absorbing structures for specified applications

AU - Siponen, Denis

AU - Uosukainen, Seppo

AU - Saarinen, Ari

PY - 2006

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N2 - In buildings there are many noise sources which are needed to be attenuated one way or another. One of these noise sources is typically air shafts. These can be passively attenuated by using absorbers and resonators or their combinations. With right design, these absorbent and resonator structures can attenuate desired frequencies efficiently. To accomplish this, however, knowledge of acoustical phenomena behind these structures and use of computer algorithms which use this knowledge is required. Structures which consist of absorbers and resonators are examined. Here they are theoretically optimized by a computer algorithm which is based on defining a structure by the transmission line model. With this kind of relatively accurate model it is possible to avoid errors made by commonly used approximate formulas. Since absorbers, which contains perforated plate and absorbent have many variable parameters their acoustical efficiencies flexibly can be optimized by finding the most suitable parameters. Optimized and modeled absorbent structures have been constructed and their respective absorption coefficients have been measured. Measured values correspond well with estimated theoretical values. With measurements it is also confirmed that optimized resonator structures are noticeably more effective than normal nonoptimized resonator structures considering acoustic functioning. Measurements of absorption coefficient have been made with a impedance tube using the twochannel method with excitation being a logarithmic sinesweep.

AB - In buildings there are many noise sources which are needed to be attenuated one way or another. One of these noise sources is typically air shafts. These can be passively attenuated by using absorbers and resonators or their combinations. With right design, these absorbent and resonator structures can attenuate desired frequencies efficiently. To accomplish this, however, knowledge of acoustical phenomena behind these structures and use of computer algorithms which use this knowledge is required. Structures which consist of absorbers and resonators are examined. Here they are theoretically optimized by a computer algorithm which is based on defining a structure by the transmission line model. With this kind of relatively accurate model it is possible to avoid errors made by commonly used approximate formulas. Since absorbers, which contains perforated plate and absorbent have many variable parameters their acoustical efficiencies flexibly can be optimized by finding the most suitable parameters. Optimized and modeled absorbent structures have been constructed and their respective absorption coefficients have been measured. Measured values correspond well with estimated theoretical values. With measurements it is also confirmed that optimized resonator structures are noticeably more effective than normal nonoptimized resonator structures considering acoustic functioning. Measurements of absorption coefficient have been made with a impedance tube using the twochannel method with excitation being a logarithmic sinesweep.

M3 - Conference article in proceedings

BT - Euronoise 2006 proceedings CD-ROM

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Siponen D, Uosukainen S, Saarinen A. Optimizing broad-band passive absorbing structures for specified applications. In Euronoise 2006 proceedings CD-ROM. Akustinen Seura ry. 2006