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A contact free measurement method to determine internal stress states in glulam

Jönsson, Johan LU and Svensson, Staffan LU (2004) In Holzforschung 58(2). p.148-153
Abstract
A method to determine the internal stress state across the grain of glued laminated wood (glulam), as well as the experimental equipment for measuring released deformation are described in this paper. The internal stress state is calculated from measured released deformations, which are measured by a contact free method based on a digital camera technique. Nondestructive measurement of the modulus of elasticity in the crossgrain direction is presented and the correlation between dynamic and static modulus of elasticity is shown. Results for a single specimen with induced moisture gradient show that the largest stress found in the tests was about 0.57 MPa, which is higher than the characteristic value of tensile strength perpendicular to... (More)
A method to determine the internal stress state across the grain of glued laminated wood (glulam), as well as the experimental equipment for measuring released deformation are described in this paper. The internal stress state is calculated from measured released deformations, which are measured by a contact free method based on a digital camera technique. Nondestructive measurement of the modulus of elasticity in the crossgrain direction is presented and the correlation between dynamic and static modulus of elasticity is shown. Results for a single specimen with induced moisture gradient show that the largest stress found in the tests was about 0.57 MPa, which is higher than the characteristic value of tensile strength perpendicular to the grain. This stress is based on released strain over the total length of the slices cut from the specimens. FEMsimulations evaluating the stress distribution within the specimen to account for end effects indicate that the maximum stress is about 30% higher. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
glulam, contact free measuring technique, released deformation, internal stress, modulus of elasticity, cross-grain direction, of measuring, accuracy, KstrWood
in
Holzforschung
volume
58
issue
2
pages
148 - 153
publisher
De Gruyter
external identifiers
  • wos:000220368000008
  • scopus:1942441757
ISSN
1437-434X
DOI
10.1515/HF.2004.022
language
English
LU publication?
yes
id
6964d816-5175-4e98-9935-288d92ff20c2 (old id 284660)
date added to LUP
2007-08-02 16:14:54
date last changed
2017-07-09 03:38:05
@article{6964d816-5175-4e98-9935-288d92ff20c2,
  abstract     = {A method to determine the internal stress state across the grain of glued laminated wood (glulam), as well as the experimental equipment for measuring released deformation are described in this paper. The internal stress state is calculated from measured released deformations, which are measured by a contact free method based on a digital camera technique. Nondestructive measurement of the modulus of elasticity in the crossgrain direction is presented and the correlation between dynamic and static modulus of elasticity is shown. Results for a single specimen with induced moisture gradient show that the largest stress found in the tests was about 0.57 MPa, which is higher than the characteristic value of tensile strength perpendicular to the grain. This stress is based on released strain over the total length of the slices cut from the specimens. FEMsimulations evaluating the stress distribution within the specimen to account for end effects indicate that the maximum stress is about 30% higher.},
  author       = {Jönsson, Johan and Svensson, Staffan},
  issn         = {1437-434X},
  keyword      = {glulam,contact free measuring technique,released deformation,internal stress,modulus of elasticity,cross-grain direction,of measuring,accuracy,KstrWood},
  language     = {eng},
  number       = {2},
  pages        = {148--153},
  publisher    = {De Gruyter},
  series       = {Holzforschung},
  title        = {A contact free measurement method to determine internal stress states in glulam},
  url          = {http://dx.doi.org/10.1515/HF.2004.022},
  volume       = {58},
  year         = {2004},
}