Mehran ROOHNIA, Abdolsaber YAGHMAEIPOUR, Yoshitaka KUBOJIMA, Ajang TAJDINI

Free vibration of both-ends clamped wooden beams: is it potentially applicable as an in situ assessment method?

Considerable errors caused by shear deflection and rotary inertia in both-ends clamped flexural vibration make the modulus of elasticity hardly obtainable in flexurally excited beams with similar ending conditions. As both-ends clamped beams and columns are necessarily quality controlled in situ within the building structures, this study has attempted to identify some initial requirements for the dynamic responses of a sound both-ends clamped beam under flexural vibration. Accordingly, the dynamic responses of the both-ends clamped wooden beams in radial and tangential flexural vibration were compared to beams in a free-free condition while stepwise increasing axial compressions were applied to the beams. Both-ends clamped beams had the potential to be subjected to in situ longitudinal Young's modulus evaluations. The strong correlations among both-ends clamped and free-free beams in terms of evaluated moduli verified the possibility.

Anahtar Kelimeler:

Key words: Assessment, beam, clamped, structure, vibration, Young's modulus

Free vibration of both-ends clamped wooden beams: is it potentially applicable as an in situ assessment method?

Keywords:

Key words: Assessment, beam, clamped, structure, vibration, Young's modulus,

PDF

___

Bodig J, Jayne BA (1989) Mechanics of Wood and Wood Composite (Persian translation by G. Ebrahimi). Tehran University Press, Iran.
Brancheriau L, Bailleres H, Sale C (2006) Acoustic resonance of xylophone bars: experimental and analytic approach of frequency shift phenomenon during the tuning operation of xylophone bars. Wood Sci Technol 40: 94–106.
Burian B (2006) Verbesserung der Rund holz vorsortierung durch die automatisierte Bestimmung von Holzstrukturmerkmalen am Beispiel der durchschnittlichen Jahrringbreite [mm] under Einsatz der Röntgentechnologie, Dissertation, Freiburger Forstliche Forschung 35 (in German with English summary). Forstliche Versuchs- und Forschungsanstalt, Freiburg, Germany.
Choi FC, Li J, Samali B, Crews K (2007) Application of modal based damage-detection method to locate and evaluate damage in timber beams. J Wood Sci 53: 394–400.
Grundberg S, Grönlund A (1997) Simulated grading of logs with an x-ray log scanner – grading accuracy compared with manual grading. Scand J Forest Res 12: 70–76.
Harris CM, Piersol AG (2002) Harris’ Shock and Vibration Handbook. McGraw-Hill, New York.
Kubojima Y, Kato H, Tonosaki M (2012) Fixed–fixed flexural vibration testing method of actual-size bars for timber guardrails. J Wood Sci 58: 211–215.
Kubojima Y, Ohsaki H, Kato H, Tonosaki M (2006) Fixed-fixed flexural vibration testing of beams for timber guardrails. J Wood Sci 52: 202–207.
Nagai H, Murata K, Nakamura M (2007) Defect determination of lumber including knots using bending deflection curve. J Soc Mater Sci 56: 326–331.
Nakao T, Okano T, Asano I (1984) Measurement of anisotropic shear modulus by the torsional-vibration method for free–free wooden beams. Mokuzai Gakkaishi 30: 877–885.
Nakayama Y (1974) Vibrational property of wooden beam containing the decrease section (in Japanese). Mokuzai Gakkaishi 20: 1–8.
Oja J, Skog J, Edlund J, Bjorklund L (2010) Deciding log grade for payment based on X-ray scanning of logs. In: Proceedings of the Final Conference of COST Action E53, “The future of quality control for wood products”, Edinburgh, UK. Available at http://www.coste53.net/downloads/Edinburgh/EdinburghPresentation/50.pdf.
Pietikäinen M (1996) Detection of knots in logs using x-ray imaging, Dissertation, VTT Publications 266, Technical Research Centre of Finland, Espoo, Finland.
Roohnia M, Alavitabar SE, Hossein MA, Brancheriau L, Tajdini A (2011a) Dynamic modulus of elasticity of drilled wooden beams. Nondestruct Test Eval 26: 141–153.
Roohnia M, Manouchehri N, Tajdini A, Yaghmaeipour A, Bayramzadeh V (2011b) Modal frequencies to estimate the defect position in a flexural wooden beam. BioResources 6: 3676–3686.
Roohnia M, Yavari A, Tajdini A (2010) Elastic parameters of poplar wood with end-cracks. Ann For Sci 67: 409.
Skog J, Oja J (2009) Combining X-ray and three-dimensional scanning of sawlogs – comparison between one and two X-ray directions. In: Proceedings of the 6th International Symposium on Image and Signal Processing and Analysis, Salzburg, Austria, pp. 343–348.
Sobue N, Nakano A (2001) Flattering of the resonance frequency by defects in wood in the longitudinal tapping method. In: Abstracts of the 51st Annual Meeting of the JWRS, p. 91.
Timoshenko SP (1921) On the correction for shear of the differential equation for transverse vibrations of prismatic bars. Philos Mag Sixth Series 41: 744–746.
Turk C, Hunt J, Marr DJ (2008) Cantilever-Beam Dynamic Modulus for Wood Composite Products: Part 1 Apparatus. Research Note FPL-RN-0308. United States Forest Service, Washington DC.
Wang X, Hagman O, Grundberg S (1997) Sorting pulpwood by X-ray scanning. In: Proceedings of the International Mechanical Pulping Conference, Stockholm, Sweden, pp. 395–399.
Yang X, Ishimaru Y, Iida I, Urakami H (2002) Application of modal analysis by transfer function to non-destructive testing of wood I: determination of localized defects in wood by the shape of the flexural vibration wave. J Wood Sci 48: 283–288.