Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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
Predicting the sound transmission loss of honeycomb panels using the wave propagation approach
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.ORCID iD: 0000-0002-9632-8398
2011 (English)In: Acta Acoustica united with Acustica, ISSN 1610-1928, Vol. 97, no 5, 869-876 p.Article in journal (Refereed) Published
Abstract [en]

The sound transmission properties of sandwich panels can be predicted with sufficient degree of accuracy by calculating the wave propagation properties of the structure. This method works well for sandwich panels with isotropic cores but applications to panels with anisotropic cores are hard to find. Honeycomb is an example of anisotropic material which when used as a core, results in a sandwich panel with anisotropic properties. In this paper, honeycomb panels are treated as being orthotropic and the wavenumbers are calculated for the two principle directions. These calculated wavenumbers are validated with the measured wavenumbers estimated from the resonance frequencies of freely hanging honeycomb beams. A combination of wave propagation and standard orthotropic plate theory is used to predict the sound transmission loss of honeycomb panels. These predictions are validated through sound transmission measurements. Passive damping treatment is a common way to reduce structural vibration and sound radiation, but they often have little effect on sound transmission. Visco-elastic damping with a constraining layer is applied to two honeycomb panels with standard and enhanced fluid coupling properties. This enhanced fluid coupling in one of the test panels is due to an extended coincidence range observed from the dispersion curves. The influence of damping treatments on the sound transmission loss of these panels is investigated. Results show that, after the damping treatment, the sound transmission loss of an acoustically bad panel and a normal panel are very similar.

Place, publisher, year, edition, pages
2011. Vol. 97, no 5, 869-876 p.
Keyword [en]
Acoustic wave transmission, Anisotropy, Architectural acoustics, Curve fitting, Damping, Honeycomb structures, Orthotropic plates, Resonance, Sandwich structures, Structural dynamics
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-12927DOI: 10.3813/AAA.918466ISI: 000295114100016Scopus ID: 2-s2.0-80052447110OAI: oai:DiVA.org:kth-12927DiVA: diva2:319649
Note
QC 20100519 QC 20111017Available from: 2010-05-19 Created: 2010-05-19 Last updated: 2012-06-11Bibliographically approved
In thesis
1. The effects of damping treatment on the sound transmission loss of honeycomb panels
Open this publication in new window or tab >>The effects of damping treatment on the sound transmission loss of honeycomb panels
2010 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In the industry, all passenger vehicles are treated with damping materials to reduce structure-borne sound. Though these damping materials are effective to attenuate structure-borne sound, they have little or no effect on the air-borne sound transmission.The lack of effective predictive methods for assessing the acoustic effects due to added damping on complex industrial structures leads to excessive use of damping materials.Examples are found in the railway industry where sometimes the damping material applied per carriage is more than one ton. The objective of this thesis is to provide a better understanding of the application of these damping materials in particular when applied to lightweight sandwich panels.

As product development is carried out in a fast pace today, there is a strong need for validated prediction tools to assist in the design process. Sound transmission loss of sandwich plates with isotropic core materials can be accurately predicted by calculating the wave propagation in the structure. A modified wave propagation approach is used to predict the sound transmission loss of sandwich panels with honeycomb cores. The honeycomb panels are treated as being orthotropic and the wave numbers are calculated for the two principle directions. The orthotropic panel theory is used to predict the sound transmission loss of panels. Visco-elastic damping with a constraining layer is applied to these structures and the effect of these damping treatment on the sound transmission loss is studied. Measurements are performed to validate these predictions.

Sound radiated from vibrating structures is of great practical importance.The radiation loss factor represents damping associated with the radiation of sound as a result of the vibrating structure and can be a significant contribution for structures around the critical frequency and for composite structures that are very lightly damped. The influence of the radiation loss factor on the sound reduction index of such structures is also studied.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2010. vii, 30 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2010:21
Keyword
Sandwich Structures, Honeycomb Panels, Sound Transmission, Loss Factor, Damping, Sound Radiation
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-12514 (URN)9789174156034 (ISBN)
Presentation
2010-04-25, MWL sal 74, Teknikringen 8, Stockholm, 13:00 (English)
Opponent
Supervisors
Projects
ECO2-Multifunctional body Panels
Note
QC 20100519Available from: 2010-05-19 Created: 2010-05-03 Last updated: 2011-05-03Bibliographically approved
2. Sound transmission properties of honeycomb panels and double-walled structures
Open this publication in new window or tab >>Sound transmission properties of honeycomb panels and double-walled structures
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sandwich panels with aluminium face sheets and honeycomb core material have certain advantages over panels made of wood. Some of the advantages of these constructions are low weight, good moisture properties, fire resistance and high stiffness to-weight ratio etc. As product development is carried out in a fast pace today, there is a strong need for validated prediction tools to assist during early design stages. In this thesis, tools are developed for predicting the sound transmission through honeycomb panels, typical for inner floors in trains and later through double-walled structures typical for rail-vehicles, aircrafts and ships.

The sandwich theory for wave propagation and standard orthotropic plate theory is used to predict the sound transmission loss of honeycomb panels. Honeycomb is an anisotropic material which when used as a core in a sandwich panel, results in a panel with anisotropic properties. In this thesis, honeycomb panels are treated as being orthotropic and the wavenumbers are calculated for the two principal directions. The wavenumbers are then used to calculate the sound transmission using standard orthotropic theory. These predictions are validated with results from sound transmission measurements. The influence of constrained layer damping treatments on the sound transmission loss of these panels is investigated. Results show that, after the damping treatment, the sound transmission loss of an acoustically bad panel and a normal pane lare very similar.

Further, sound transmission through a double-leaf partition based on a honeycomb panel with periodic stiffeners is investigated. The structural response of the periodic structure due to a harmonic excitation is expressed in terms of a series of space harmonics and virtual work theory is applied to calculate the sound transmission. The original model is refined to include sound absorption in the cavity and to account for the orthotropic property of the honeycomb panels. Since the solution of the space harmonic analysis is obtained in a series form, a sufficient number of terms has to be included in the calculation to ensure small errors. Computational accuracy needs to be balanced with computational cost as calculation times increases with the number of terms. A new criterion is introduced which reduces the computational time by up to a factor ten for the panels studied. For all the double-leaf systems analysed, the sound transmission loss predictions from the periodic model with the space harmonic expansion method are shown to compare well with laboratory measurements.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. xi, 74 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2012:20
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-96538 (URN)978-91-7501-334-3 (ISBN)
Public defence
2012-06-14, F3, Lindstedtsvägen 26, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note

QC 20120607

Available from: 2012-06-07 Created: 2012-06-06 Last updated: 2013-04-11Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Feng, Leping

Search in DiVA

By author/editor
Ramanathan, Sathish KumarFeng, Leping
By organisation
MWL Structural and vibroacoustics
In the same journal
Acta Acoustica united with Acustica
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 260 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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