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Internal stresses in glulam due to moisture gradients in the grain direction

Jönsson, Johan LU (2005) In Holzforschung 59(1). p.18-22
Abstract
An experimental study on the internal stress state perpendicular to grain in glued laminated timber induced by moisture variations along the grain is presented. The stress is evaluated by using measured modulus of elasticity and strain. Different types of tests are performed, in which specimens are exposed to artificial climate change when the specimens are in either a wetting or a drying state, and specimens are exposed to a cyclic climate change. Test results from the specimens that were in a drying state show that the tensile stresses near the end of the specimens at some point exceeds the strength of the wood and cracks. In the opposite test, when the specimens are in a moistening phase, the maximum tensile stresses are lower and in... (More)
An experimental study on the internal stress state perpendicular to grain in glued laminated timber induced by moisture variations along the grain is presented. The stress is evaluated by using measured modulus of elasticity and strain. Different types of tests are performed, in which specimens are exposed to artificial climate change when the specimens are in either a wetting or a drying state, and specimens are exposed to a cyclic climate change. Test results from the specimens that were in a drying state show that the tensile stresses near the end of the specimens at some point exceeds the strength of the wood and cracks. In the opposite test, when the specimens are in a moistening phase, the maximum tensile stresses are lower and in the order of 0.2 MPa during the tested period. The cyclic test, which continued during 20 weeks, showed that there were no accumulated effects regarding strain and stress values. In this test, the average maximum tensile and compression stresses were of the order 0.20 and 0.10 MPa, respectively. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
crossgrain direction, contact free measuring technique, glulam, internal stress, released deformation, moisture gradients, KstrWood, technique, slicing
in
Holzforschung
volume
59
issue
1
pages
18 - 22
publisher
De Gruyter
external identifiers
  • wos:000226983300003
  • scopus:14044260744
ISSN
1437-434X
DOI
10.1515/HF.2005.003
language
English
LU publication?
yes
id
3ecd762e-ab65-4b3d-8973-7424d64fe1c1 (old id 254498)
date added to LUP
2007-08-15 11:25:54
date last changed
2017-01-01 05:09:09
@article{3ecd762e-ab65-4b3d-8973-7424d64fe1c1,
  abstract     = {An experimental study on the internal stress state perpendicular to grain in glued laminated timber induced by moisture variations along the grain is presented. The stress is evaluated by using measured modulus of elasticity and strain. Different types of tests are performed, in which specimens are exposed to artificial climate change when the specimens are in either a wetting or a drying state, and specimens are exposed to a cyclic climate change. Test results from the specimens that were in a drying state show that the tensile stresses near the end of the specimens at some point exceeds the strength of the wood and cracks. In the opposite test, when the specimens are in a moistening phase, the maximum tensile stresses are lower and in the order of 0.2 MPa during the tested period. The cyclic test, which continued during 20 weeks, showed that there were no accumulated effects regarding strain and stress values. In this test, the average maximum tensile and compression stresses were of the order 0.20 and 0.10 MPa, respectively.},
  author       = {Jönsson, Johan},
  issn         = {1437-434X},
  keyword      = {crossgrain direction,contact free measuring technique,glulam,internal stress,released deformation,moisture gradients,KstrWood,technique,slicing},
  language     = {eng},
  number       = {1},
  pages        = {18--22},
  publisher    = {De Gruyter},
  series       = {Holzforschung},
  title        = {Internal stresses in glulam due to moisture gradients in the grain direction},
  url          = {http://dx.doi.org/10.1515/HF.2005.003},
  volume       = {59},
  year         = {2005},
}