Evaluation of Tsai–Wu criterion and Hankinson's formula for a Brazilian wood species by comparison with experimental off-axis strength tests

Abstract

This article presents a study based on the Tsai–Wu failure criterion as well as Hankinson's formula that evaluates the off-axis strength of wood. For materials such as wood, the strengths are a function of the grain orientation and also are different in compression and tension for the same direction. By considering this anisotropic behaviour, the failure criterion of the Tsai–Wu was adopted in this work. To establish this criterion, the strengths were determined from compressive and tensile tests as well as shear and biaxial compressive tests. In addition, off-axis uniaxial tests were performed, and the experimental results were compared with those obtained by the discussed criteria. In these tests, specimens of Goupia glabra-Brazilian wood species were used. This study's most important conclusion was: the predictive ability of the Tsai–Wu criterion was close to that of Hankinson's formula and fits the experimental results of the compressive and tensile tests well.

Keywords:

• Failure criteria
• hardwood
• off-axis strengths
• orthotropic materials
• axial test

Acknowledgements

The authors gratefully acknowledge CNPq (no. 301504/2004-0) and FAPESP(no. 2004/15481-5), Brazilian Foundations, for the financial supporting of this research.