Determination of shear modulus on construction size timber
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Shear modulus determination of construction size timber was examined. Three different Techniques were used: torsional vibration, simultan E&G, and variation of span technique. We found that the simultan E&G technique is quite sensitive to the error of natural frequency determination and provides only an estimate for G. Better shear modulus determinations are the static and torsional techniques, but the torsional technique is most precise. The torsional vibration technique can be a good solution for shear modulus determination in an industrial environment because it provides quick and precise etermination, but standardization of the method would first be necessary. We found a high correlation coefficient (0.80) between the screw withdrawal resistance and shear modulus of 2 by 4 timber. Based on this result it is possible to estimate the shear modulus of timber even if the timber is installed in a structure.
KeywordsShear Modulus Timber Torsional Vibration Frequency Determination Industrial Environment
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- ASTM D198-84 (1984) Standard Method of Static Tests of Timbers in Structural Size, Annual Books of ASTM Standards, Section 4, Construction, volume 04.09 WoodGoogle Scholar
- Chui YH, Smith I (1989) Influence of rotary inertia and shear deformation and support condition on natural frequencies of wooden beams, Wood Sci. Technol. 24: 233–245Google Scholar
- Divos F (1994) Screw Withdrawal Force as Strength Predictor, Proc. First Europen Symposium on Nondestructive Evaluation of Wood, Sopron, Hungary, pp. 531Google Scholar
- EN-408 (1995) Timber structures — Structural timber and glued laminated timber — Determination of some physical and mechanical propertiesGoogle Scholar
- Hammersley JM (1964) Monte Carlo methods, Methuen, LondonGoogle Scholar
- Hearmon RFS (1966) Vibration Testing of Wood, Forest Prod. J. 16(8): 29–40Google Scholar
- Perstorper M (1994) Quality of structural lumber, Chalmers University, Department of Structural Engineering, Thesis, Goteborg, SwedenGoogle Scholar
- Schneider H (1966) Verfahren zur Berechnung von Elastizitats- und Schubmodul aus Eigenfrequenzen stabförmiger Proben, Materialprüf. 8(5): 169–174Google Scholar
- Tanaka T, Nagao H, Nakai T (1991) Nondestructive evaluation of bending and tensile strength by longitudinal and transverse vibration of lumber. Proc. 8th International Symposium on Nondestructive Testing of Wood. Washington State university, Pullman, USAGoogle Scholar
- Timoshenko S (1954) Vibration Problems in Engineering, Van Nostrand, New YorkGoogle Scholar
- Wuolijoki J (1947) The simultaneous estimation of elasticity and shear modulus from the overtones of a road in bending vibration. Thesis, Finnish Technical High School, HelsinkiGoogle Scholar