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
The influence of tyre air cavities on vehicle acoustics
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
2006 (English)Doctoral thesis, monograph (Other scientific)
Abstract [en]

The tonal character of the low frequency internal noise in cars is often due to energy transmission through the tyre at the first few eigenfrequencies of the air cavity of the tyre. The first acoustic mode in the air cavity of a typical stationary car tyre is approximately 224 Hz. At this frequency the tyre is comparatively stiff resulting in a high transmission of energy from the road wheel contact to the car body itself. In order to investigate possible means of reducing this effect, the acoustic field inside a tyre is modelled. Theoretically it is found that the pressure inside a tyre and the energy transmission through the tyre to the wheel axle and the car body can be reduced by adding a sound absorbing material inside the tyre. This was confirmed by measurements on stationary as well as rotating tyres with and without added sound absorption. For a rotating tyre there is a split of the natural frequency depending on the rotational speed of the tyre. Measurements in a standard passenger car reveal that the noise level inside the car is rather high in a fairly wide frequency range around 224 Hz at normal velocities. This tonal noise can be reduced by adding sound absorption inside a tyre. Models for the prediction and the reduction of the tonal noise are presented. Measured and predicted results are compared and the agreement is found to be good. It is found that the tonal noise can be reduced by up to 9 dB.

The effects of the air cavity resonances on the external noise have also been studied. It is estimated that external tyre noise can be reduced 1 dB by adding a sound absorbing material inside tyres.

For a car travelling on a road a strong acoustic field is induced between the floor of the car and the road. The impact of this acoustic field can be reduced by mounting a sound absorbing material underneath the car. It is estimated that the A-weighted sound pressure level close to a running car could be reduced by 3 dB by adding this type sound absorption.

It is found that aluminium foam could be a suitable sound absorbing material which could be mounted inside tyres and underneath cars. The acoustic and dynamic properties of various types of aluminium foams are discussed. In particular measurement techniques for determining sound absorption at grazing incidence are investigated.

Place, publisher, year, edition, pages
Stockholm: KTH , 2006. , p. 190
Series
Trita-AVE, ISSN 1651-7660 ; 2006:67
Keyword [en]
acoustics, tyre-road noise, tyre, air cavity resonances, interior noise, aluminium foams
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-4132OAI: oai:DiVA.org:kth-4132DiVA: diva2:10874
Public defence
2006-10-26, Sal V3, KTH, Teknikringen 72, Stockholm, 13:00
Opponent
Supervisors
Note
QC 20100923Available from: 2006-10-06 Created: 2006-10-06 Last updated: 2010-09-23Bibliographically approved

Open Access in DiVA

fulltext(14895 kB)3342 downloads
File information
File name FULLTEXT01.pdfFile size 14895 kBChecksum SHA-1
d9f9ebdf6dee24e8e9c23c94d23cc2fecd3cd33fb3925da506390c3177a610b930dbe653
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Torra i Fernàndez, Èric
By organisation
Aeronautical and Vehicle Engineering
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar
Total: 3342 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: 927 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