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Moisture content prediction of rain-exposed wood: Test and evaluation of a simple numerical model for durability applications

Niklewski, Jonas LU ; Fredriksson, Maria LU and Isaksson, Tord LU (2016) In Building and Environment 97(February). p.126-136
Abstract (Swedish)
Abstract in French

Decay-prediction models can be used to predict the service life of wooden components. However, knowledge of how the material climate, i.e. moisture content and material temperature, varies with time is required. A reliable material climate prediction model is therefore crucial in situations when measurements are not viable. The aim of this paper is to develop and assess the performance of a simple numerical moisture transport model for rain-exposed wood. The main focus is on the influence of rain and moisture transport in the transversal direction.

First, a model based on Fick’s second law of diffusion was calibrated against laboratory measurements where wooden boards were exposed to artificial... (More)
Abstract in French

Decay-prediction models can be used to predict the service life of wooden components. However, knowledge of how the material climate, i.e. moisture content and material temperature, varies with time is required. A reliable material climate prediction model is therefore crucial in situations when measurements are not viable. The aim of this paper is to develop and assess the performance of a simple numerical moisture transport model for rain-exposed wood. The main focus is on the influence of rain and moisture transport in the transversal direction.

First, a model based on Fick’s second law of diffusion was calibrated against laboratory measurements where wooden boards were exposed to artificial rain. Second, the model was tested against field-test measurements on wooden boards in use-class 3.1, i.e. above-ground, exposed to rain and free to dry. The influence of rain was investigated by studying the difference between sheltered and exposed specimens over time. Finally, the model was applied to a number of Swedish climates and two different decay-prediction models were used to assess the output.

The main conclusion is that the influence of rain can be reproduced with sufficient accuracy for the particular application. The error between the numerical result and measurements tends to increase with decreasing temperature and at high moisture contents. However, the total error is reduced when the moisture content history is post-processed in a decay-prediction model as the rate of decay decreases with decreasing temperature. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
moisture content, decay prediction, wood, durability
in
Building and Environment
volume
97
issue
February
pages
126 - 136
publisher
Elsevier
external identifiers
  • Scopus:84951284064
  • WOS:000369678200013
ISSN
1873-684X
DOI
10.1016/j.buildenv.2015.11.037
language
English
LU publication?
yes
id
b244d040-1fba-4e5d-aaae-64580caad8c6 (old id 8860525)
date added to LUP
2016-03-18 11:57:52
date last changed
2017-02-12 04:21:57
@article{b244d040-1fba-4e5d-aaae-64580caad8c6,
  abstract     = {<b>Abstract in French</b><br/><br>
Decay-prediction models can be used to predict the service life of wooden components. However, knowledge of how the material climate, i.e. moisture content and material temperature, varies with time is required. A reliable material climate prediction model is therefore crucial in situations when measurements are not viable. The aim of this paper is to develop and assess the performance of a simple numerical moisture transport model for rain-exposed wood. The main focus is on the influence of rain and moisture transport in the transversal direction. <br/><br>
First, a model based on Fick’s second law of diffusion was calibrated against laboratory measurements where wooden boards were exposed to artificial rain. Second, the model was tested against field-test measurements on wooden boards in use-class 3.1, i.e. above-ground, exposed to rain and free to dry. The influence of rain was investigated by studying the difference between sheltered and exposed specimens over time. Finally, the model was applied to a number of Swedish climates and two different decay-prediction models were used to assess the output. <br/><br>
The main conclusion is that the influence of rain can be reproduced with sufficient accuracy for the particular application. The error between the numerical result and measurements tends to increase with decreasing temperature and at high moisture contents. However, the total error is reduced when the moisture content history is post-processed in a decay-prediction model as the rate of decay decreases with decreasing temperature.},
  author       = {Niklewski, Jonas and Fredriksson, Maria and Isaksson, Tord},
  issn         = {1873-684X},
  keyword      = {moisture content,decay prediction,wood,durability},
  language     = {eng},
  number       = {February},
  pages        = {126--136},
  publisher    = {Elsevier},
  series       = {Building and Environment},
  title        = {Moisture content prediction of rain-exposed wood: Test and evaluation of a simple numerical model for durability applications},
  url          = {http://dx.doi.org/10.1016/j.buildenv.2015.11.037},
  volume       = {97},
  year         = {2016},
}