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FEM modelling of sound reduction index in partition CLT wall

Hultin, Adam LU and Hörström, Erik (2020) In TVBA-5000 VTAM01 20191
Department of Construction Sciences
Engineering Acoustics
Abstract
Constructing buildings with wood brings many advantages, especially regarding environmental aspects, which has brought an up-rise in these types of structures. However, one of the main issues regarding wooden structures is its tendency to perform poorly acoustically in lower frequencies compared to heavier structures. This often leads to unwanted noise levels which could be avoided in earlier design stages with tools that predicts the vibroacoustic response. Predicting the vibroacoustic response of buildings constructed with wood is challenging much due to its irregular material parameters. Wood is an orthotropic material meaning it has varying stiffness and strength in different directions. It is also an organic material which brings a... (More)
Constructing buildings with wood brings many advantages, especially regarding environmental aspects, which has brought an up-rise in these types of structures. However, one of the main issues regarding wooden structures is its tendency to perform poorly acoustically in lower frequencies compared to heavier structures. This often leads to unwanted noise levels which could be avoided in earlier design stages with tools that predicts the vibroacoustic response. Predicting the vibroacoustic response of buildings constructed with wood is challenging much due to its irregular material parameters. Wood is an orthotropic material meaning it has varying stiffness and strength in different directions. It is also an organic material which brings a variation in stiffness and strength not only between different species of trees, but also within the same species. In order to have building elements with less variation regarding these parameters, different engineered wood products (EWPs) has emerged on the market during the last decades. Cross-laminated timber (CLT) is an increasingly popular product in the wooden building industry which demands for more research of its vibroacoustic performance.

In this thesis a finite element model was created to predict the airborne sound insulation of a five-layer CLT slab in the low-frequency range of 1-200 Hz. Different measurements, such as experimental modal analysis and sound pressure level measurements, were performed to calibrate the model as well as validate the results obtained from it. The thesis shows that the airborne sound insulation can be predicted with a finite element model, but only together with measurements determining the material parameters and damping of the CLT under evaluation. The damping was shown to have a crucial impact on the results. The airborne sound insulation is determined in the model at the excited resonance frequencies of a plate due to a pressure load resembling airborne sound. (Less)
Popular Abstract (Swedish)
Idag byggs allt fler hus i trä tack vare de många fördelarna trä har som byggnadsmaterial. Dels är miljöpåverkan mycket mindre i jämförelse med andra material som betong,dels är det ett väldigt lätt byggnadsmaterial. Den stora nackdelen med träkonstruktioner är dock dess akustiska egenskaper. Det är ofta svårt att uppnå de ljud krav som ställs på byggnader när man väljer en träkonstruktion, vilket gör det viktigt att i tidiga skeden kunna förutspå hur dessa typer av byggnader kommer att bete sig akustiskt.
Please use this url to cite or link to this publication:
author
Hultin, Adam LU and Hörström, Erik
supervisor
organization
alternative title
FEM-modellering av reduktion av ljud i väggar av CLT
course
VTAM01 20191
year
type
H3 - Professional qualifications (4 Years - )
subject
publication/series
TVBA-5000
report number
TVBA-5058
ISSN
0281-8477
language
English
id
9004869
alternative location
http://www.akustik.lth.se/english/publications/tvba-5000/
date added to LUP
2020-02-27 09:16:27
date last changed
2020-02-27 09:16:27
@misc{9004869,
  abstract     = {{Constructing buildings with wood brings many advantages, especially regarding environmental aspects, which has brought an up-rise in these types of structures. However, one of the main issues regarding wooden structures is its tendency to perform poorly acoustically in lower frequencies compared to heavier structures. This often leads to unwanted noise levels which could be avoided in earlier design stages with tools that predicts the vibroacoustic response. Predicting the vibroacoustic response of buildings constructed with wood is challenging much due to its irregular material parameters. Wood is an orthotropic material meaning it has varying stiffness and strength in different directions. It is also an organic material which brings a variation in stiffness and strength not only between different species of trees, but also within the same species. In order to have building elements with less variation regarding these parameters, different engineered wood products (EWPs) has emerged on the market during the last decades. Cross-laminated timber (CLT) is an increasingly popular product in the wooden building industry which demands for more research of its vibroacoustic performance.

In this thesis a finite element model was created to predict the airborne sound insulation of a five-layer CLT slab in the low-frequency range of 1-200 Hz. Different measurements, such as experimental modal analysis and sound pressure level measurements, were performed to calibrate the model as well as validate the results obtained from it. The thesis shows that the airborne sound insulation can be predicted with a finite element model, but only together with measurements determining the material parameters and damping of the CLT under evaluation. The damping was shown to have a crucial impact on the results. The airborne sound insulation is determined in the model at the excited resonance frequencies of a plate due to a pressure load resembling airborne sound.}},
  author       = {{Hultin, Adam and Hörström, Erik}},
  issn         = {{0281-8477}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{TVBA-5000}},
  title        = {{FEM modelling of sound reduction index in partition CLT wall}},
  year         = {{2020}},
}