ISSN: 0090-3973
Page Count: 12

Finite-Element Analysis of the Stress Distribution in a Torsion Test of Full-Size, Structural Lumber

Gupta, R
Associate professor,Oregon State University,OR,

Heck, LR
Designer,Degenkolb Engineers, Inc.,OR,

Miller, TH
Associate professor,Oregon State University,OR,

(Received 18 September 2001; accepted 20 March 2002)

Abstract

Full-size structural lumber under torsion was analyzed using the finite-element method to determine stress distribution. A three-dimensional, homogeneous, orthotropic finite-element model was developed and analyzed using commercially available software, ANSYS®, to increase understanding of stress distribution and failure modes. Analyses revealed that uniform shear stress occurs within the shear span, which begins and ends at a distance of approximately two times the depth plus the grip distance away from each end of the specimen. In addition, finite-element analysis verified that the experimental shear-failure plane that occurs within the shear span is parallel to the grain. Shear slippage is also parallel to the grain, similar to the known shear-failure mode in specimens subjected to transverse loads. Based on results of this study, the torsion test is the best practical method to determine the pure shear strength of full-size, structural lumber.

Keywords:
wood engineering, timber, mechanical properties, shear modeling, shear-stress distribution, finite-element analysis

Paper ID: JTE12319J
DOI: 10.1520/JTE12319J
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