Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Design of soundproof panels via metamaterial concept
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.ORCID iD: 0000-0002-7547-6535
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The goal of the work is to find a way to improve the sound insulation properties of different types of panels in order to meet different requirements. Inspired by the nontrivial behavior of the locally resonant acoustic metamaterials, this concept is introduced into the design of structures in order to explore the potential ways to improve the sound insulation behavior in the relevant specific frequency regions. At relatively low frequency region when the bending wavelength is much longer than the distance between isolated resonators, which is also the interesting frequency range in the most part of the work, it may be assumed that the effects of the resonators are uniformly distributed over the entire surface. An impedance approach is hence proposed to estimate the sound transmission loss of the metamaterial panels in order to get more insights from physics. This is realized, in general, by integrating the equivalent impedance of the resonators together with the corresponding impedance of the host panel. Valuable theories are derived based on that, laying a solid foundation for effective/efficient design of metamaterial panels. This approach also provides a fast and reliable tool for the designs prior to a time-consuming and computationally expensive numerical simulation. Based on that, a new design for locally resonant metamaterial sandwich plates is proposed to improve the sound transmission loss performance in the coincidence frequency region. A systematic method to tune the resonance frequency of local resonators is developed. This approach also supplies a method to remove the possible side-dips associated with the resonance of the resonators. The influence of the sound radiation from the resonators is further investigated with the Finite Element models. It is proposed to embed the resonators inside the core material in order to eliminate the possible influence, and also to make a smooth surface. The metamaterial sandwich panel designed in this way combines improved acoustic insulation properties with the lightweight nature of the sandwich panel. Besides the coincidence frequency region, the ring frequency area of a cylindrical shell is another important frequency region for bad sound transmission loss. The effectiveness of locally resonant metamaterial is also investigated. Similar to the case of the flat panel, both impedance model and Finite Element model are developed for the problem of the sound transmission loss properties. The influence of the resonators is presented, and compared with the case of the flat panel. Unlike the case of the metamaterial flat panel, two side-dips around the sharp improvement cannot be avoided when applying the resonators near the ring frequency of the curved panel. The reason for that is explored by using the impedance approach. It is noticed that, while the impedance of a flat panel near the critical frequency is shifted from a masstype impedance to stiffness-type impedance, the impedance of a cylindrical shell is shifted from a stiffness-type (tension-type) impedance to mass-type iv impedance. For a traditional mass-spring type resonator, however, the equivalent impedance is always shifted from a mass-type impedance to stiffness-type impedance when the frequency crosses the resonance frequency. Therefore, when the traditional resonators are applied near the ring frequency, there are always frequencies at which the impedances cancel each other, resulting in the worsened sound transmission loss. In order to have better improvement of the sound transmission loss in this frequency region, new types of resonators have to be developed. A locally resonant metamaterial curved double wall is proposed and studied, with the aim of addressing the mass-spring-mass resonance and ring frequency effects of the wall. The sound transmission loss properties of a curved double wall are first investigated by introducing the concept of ‘apparent impedance’, which expresses the properties of the entire structure in terms of the impedances of the constituting panels and air cavity. The apparent impedance derivation is validated against Finite Element models. The curved double wall is then specifically designed by adjusting the two characteristic frequencies to be close to each other in order to narrow the region associated with a poor transmission loss. This enables, subsequently, to improve the transmission loss in this region by effectively inserting tuned local resonators. The design principles are discussed, and applications for double walls consisting the same curved panels or different curved panels are both included.

Place, publisher, year, edition, pages
Stockholm, Sweden: KTH Royal Institute of Technology, 2019. , p. 54
Series
TRITA-SCI-FOU ; 2019:10
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-245456OAI: oai:DiVA.org:kth-245456DiVA, id: diva2:1294736
Public defence
2019-03-27, F3, Lindstedtsvägen 26, Sing-Sing, floor 2, KTH Campus, Stockholm, 10:15 (English)
Supervisors
Note

QC 20190308

Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-03-08Bibliographically approved
List of papers
1. Suppression of the vibration and sound radiation of a sandwich plate via periodic design
Open this publication in new window or tab >>Suppression of the vibration and sound radiation of a sandwich plate via periodic design
Show others...
2019 (English)In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 150, p. 744-754Article in journal (Refereed) Published
Abstract [en]

This paper investigates the suppression of vibration and sound radiation of a sandwich plate through the use of periodic design. A periodic sandwich plate is constructed and its dispersion relation is calculated. The vibration and sound radiation properties of the periodic sandwich plate are studied. Via the comparison of the periodic and bare sandwich plate, the effects of the periodic design on the vibration and sound radiation are analysed. Further, to know the sound radiation properties better, sound radiation efficiency of the periodic and bare sandwich plates is compared. In addition, the effects of the boundary conditions on the properties of the periodic sandwich plate are analysed. The numerical results demonstrate that the vibration and sound radiation are greatly suppressed over the stop band of the periodic sandwich plate. The suppression can also be obtained in part of pass bands. It is also shown that the periodic design can be an effective method for the reduction of the sound radiation efficiency. The suppression for the vibration and sound is greater than that caused by only increasing the mass of the plate in the designing frequency range.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-244465 (URN)10.1016/j.ijmecsci.2018.10.055 (DOI)000458597800064 ()2-s2.0-85056234548 (Scopus ID)
Note

QC 20190305

Available from: 2019-02-21 Created: 2019-02-21 Last updated: 2019-03-08Bibliographically approved
2. Broadband locally resonant metamaterial sandwich plate for improved noise insulation in the coincidence region
Open this publication in new window or tab >>Broadband locally resonant metamaterial sandwich plate for improved noise insulation in the coincidence region
2018 (English)In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 200, p. 165-172Article in journal (Refereed) Published
Abstract [en]

A new design for locally resonant metamaterial sandwich plates is proposed in this paper for noise insulation engineering applications. A systematic method to tune the resonance frequency of local resonators is developed in order to overcome the coincidence phenomenon. This method, based on an impedance approach, additionally explains the ability to overcome the antiresonance associated with these local resonators. The influence of the radiated sound from these local resonators is further investigated with finite element (FE) models, particularly in connection with the sound transmission loss (STL) of the resulting metamaterial sandwich plates. The new sandwich design proposed emerges from these analyses, encapsulating the resonators inside the core material. In addition to overcoming the coincidence effect and limiting the noise radiation by the resonators, the proposed design allows to improve the mass ratio of the metamaterial sandwich structure. This, in turn, enables to broaden the working frequency band independently of the material adopted for the resonator. The proposed metamaterial sandwich plate thus combines improved acoustic insulation properties, while maintaining the lightweight nature of the sandwich plate and its good static properties.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Acoustic metamaterial, Sandwich plate, Sound transmission loss, Coincidence frequency
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-232743 (URN)10.1016/j.compstruct.2018.05.033 (DOI)000439466100016 ()2-s2.0-85047501239 (Scopus ID)
Funder
Swedish Research Council, 2015-04925VINNOVA, 2016-05195
Note

QC 20180807

Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2019-03-08Bibliographically approved
3. Investigation of the sound transmission through a locally resonant metamaterial cylindrical shell in the ring frequency region
Open this publication in new window or tab >>Investigation of the sound transmission through a locally resonant metamaterial cylindrical shell in the ring frequency region
(English)In: Article in journal (Refereed) Accepted
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-245454 (URN)
Note

QC 20190308

Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-03-08Bibliographically approved
4. Locally resonant metamaterial curved double wall to improve sound insulation at the ring frequency and mass-spring-mass resonance
Open this publication in new window or tab >>Locally resonant metamaterial curved double wall to improve sound insulation at the ring frequency and mass-spring-mass resonance
(English)In: Article in journal (Refereed) Submitted
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-245455 (URN)
Note

QC 20190308

Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-03-08Bibliographically approved

Open Access in DiVA

fulltext(10128 kB)286 downloads
File information
File name FULLTEXT01.pdfFile size 10128 kBChecksum SHA-512
88f8b57d8418b501c8bb1a0fdc2ee2fbb7befc5ac7b3169054d89dccea326631593a89bcdfab36f89f656a844c9b8ac96fd08d76c9737ad416ff3056a0ec4f2a
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Liu, Zibo
By organisation
Marcus Wallenberg Laboratory MWL
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar
Total: 286 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 280 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf