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Mechanical response of wood perpendicular to grain when subjected to changes of humidity

Svensson, Staffan LU and Toratti, Tomi (2002) In Wood Science and Technology 36(2). p.145-156
Abstract
This paper describes the deformations caused by stress and humidity interaction, mechano-sorption, in the cross grain directions of wood and the relaxation or accumulation of internal stresses caused by these deformations. Long-term tests on small clear specimens in cyclic climates with both tensile and compressive loads were carried out. The development of internal stresses in timber was measured indirectly at different times during the adsorption and desorption processes. Released deformations were measured from cross-sections after cutting them to small slices. These deformations were used to estimate the internal stresses caused by the humidity variations. Tests with constant loads and multiple humidity cycles show a mechano-sorptive... (More)
This paper describes the deformations caused by stress and humidity interaction, mechano-sorption, in the cross grain directions of wood and the relaxation or accumulation of internal stresses caused by these deformations. Long-term tests on small clear specimens in cyclic climates with both tensile and compressive loads were carried out. The development of internal stresses in timber was measured indirectly at different times during the adsorption and desorption processes. Released deformations were measured from cross-sections after cutting them to small slices. These deformations were used to estimate the internal stresses caused by the humidity variations. Tests with constant loads and multiple humidity cycles show a mechano-sorptive strain that is ten times higher than the elastic strain. It is shown that existing models for describing mechano-sorption perpendicular to grain are inaccurate when applied to multiple humidity cycles. The present results demonstrate that if the mechano-sorptive behaviour and the moisture gradients in wood can be accurately described, it is possible to predict the stress distribution in a timber cross-section by knowing the climate history. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Wood Science and Technology
volume
36
issue
2
pages
145 - 156
publisher
Springer
external identifiers
  • wos:000175336000004
  • scopus:0036541659
ISSN
1432-5225
DOI
10.1007/s00226-001-0130-4
language
English
LU publication?
yes
id
868a3cc8-e259-4486-bccb-663ee9a3baac (old id 338741)
date added to LUP
2007-11-15 12:27:09
date last changed
2017-11-19 04:03:31
@article{868a3cc8-e259-4486-bccb-663ee9a3baac,
  abstract     = {This paper describes the deformations caused by stress and humidity interaction, mechano-sorption, in the cross grain directions of wood and the relaxation or accumulation of internal stresses caused by these deformations. Long-term tests on small clear specimens in cyclic climates with both tensile and compressive loads were carried out. The development of internal stresses in timber was measured indirectly at different times during the adsorption and desorption processes. Released deformations were measured from cross-sections after cutting them to small slices. These deformations were used to estimate the internal stresses caused by the humidity variations. Tests with constant loads and multiple humidity cycles show a mechano-sorptive strain that is ten times higher than the elastic strain. It is shown that existing models for describing mechano-sorption perpendicular to grain are inaccurate when applied to multiple humidity cycles. The present results demonstrate that if the mechano-sorptive behaviour and the moisture gradients in wood can be accurately described, it is possible to predict the stress distribution in a timber cross-section by knowing the climate history.},
  author       = {Svensson, Staffan and Toratti, Tomi},
  issn         = {1432-5225},
  language     = {eng},
  number       = {2},
  pages        = {145--156},
  publisher    = {Springer},
  series       = {Wood Science and Technology},
  title        = {Mechanical response of wood perpendicular to grain when subjected to changes of humidity},
  url          = {http://dx.doi.org/10.1007/s00226-001-0130-4},
  volume       = {36},
  year         = {2002},
}