Vibration methods as non-destructive tool for structural properties assessment of sawn timber
DOI:
https://doi.org/10.3989/ic.2007.v59.i506.512Keywords:
non-destructive testing, resonant frequency, gross cross-section structural saw timber, PLG (Portable Lumber Grader)Abstract
The non-destructive testing of structural sawn timber using the resonant frequency methods uses the natural frequency of pieces to assess the quality of test samples.
This paper describes the theoretical basis of this non-destructive technique and an investigation into the suitability of this tool. The results of grading 120 pieces of gross cross-section (150 x 200 x 4,060 mm and 200 x 250 x 5,060 mm) structural timber of European black pine, (Pinus nigra subsp. salzmannii (Dunal) Franco) are shown.
Furthermore, the specimens were tested for bending according to the UNE-EN 408: 2004 standard, to compare the values of strength and stiffness obtained from this test with the results estimated using the non-destructive method. PLG (the Portable Lumber Grader) developed at the Wood NDT Laboratory of the University of Western Hungary, in Sopron, was used to measure the frequency of the longitudinal stress wave. This equipment determines the frequency and the density of the specimens, and uses them, to evaluate the dynamic modulus of elasticity and to estimate the strength.
For gross cross-section European black pine pieces, a strong relationship exists between dynamic modulus obtained by longitudinal vibration frequency and the mechanical properties. Acoustic measurements have become widely acceptable, because they are accurate, portable, cheap and easy to apply.
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(1) Ley 38/1999, de 5 de noviembre, de Ordenación de la Edificación.
(2) Código Técnico de la Edificación. Ministerio de la Vivienda. Marzo 2006.
(3) UNE 56544: 2003. Clasificación visual de la madera aserrada para uso estructural. Madera de coníferas.
(4) UNE 56546. Clasificación visual de la madera aserrada para uso estructural. Madera de frondosas.
(5) Pellerin, R.F.; Ross, R.J. Nondestructive evaluation of wood. 210 p. Forest Products Society. Madison, WI, USA. 2002.
(6) Bucur, V. Acoustics of wood. 2nd Ed. Heidelberg: Springer Verlag. 455 p. 2006.
(7) Malhotra, V.M.; Carino, N.J. Handbook on Nondestructive Testing of Concrete. CRC Press, 2nd edition. 384 p. 2003.
(8) Arriaga, F.; Íñiguez, G.; Esteban, M. “Assessment of strength and stiffness properties using longitudinal stress wave on structural gross cross section timber of radiata pine (Pinus radiate D. Don).” Proceedings of the 14th International Symposium on Nondestructive Testing of Wood. Hannover 2 - 4 may 2005. Published by Shaker Verlag, Germany (2005), pp. 101 - 110.
(9) Divos, F. ´’Course in Non-Destructive Testing of Wood. Apuntes y presentaciones del curso’´. Madrid 13-16 junio 2005. ETS Ingenieros de Montes - ETS Arquitectura, UPM, Madrid. 2005.
(10) Weaver, W.; Timoshenko S.P.; Young, D.H. ´’Vibration problems in engineering’´. John Wiley & Sons Limited. 5th Edition. 610 p. 1990.
(11) Sobue, N. “Instantaneous measurement of elastic constants by analysis of the tap tone of wood. Application to fl exural vibration of beams.” Mokuzai Gakkaishi, 32 (4) (1986a), pp. 274 - 279.
(12) Sobue, N. “Measurement of Young’s modulus by the transient longitudinal vibration of wooden beams using a FFT spectrum analyser.” Mokuzai Gakkaishi, 32 (9) (1986b), pp. 744 - 747.
(13) Sobue, N. “Simultaneous determination of Young’s modulus and shear modulus of structural lumber of complex vibrations of bending and twisting.” Mokuzai Gakkaishi, 34 (8). (1988), pp. 652 - 657.
(14) Obert, L.; Duvall, W.I. “Discussion of dynamic methods of testing concrete with suggestions for standardization.” Proc. ASTM, 41, 1053 (1941).
(15) Kesler, C.E.; Higuchi, Y. “Problems in the sonic testing of plain concrete.” Proceedings of the International Symposium on Nondestructive Testing of Materials and Structures. Paris, 1954. Vol. 1 published by RILEM (1954). 45 p.
(16) Li, J.; Samali, B.; Crews, K. “Determining individual member stiffness of bridge structures using a simple dynamic procedure.” Acoustics Australia, 32 (1) (2004), pp. 9 - 12.
(17) Wang, X.; Wacker, J.P.; Morison, A.M.; Forsman, J.W.; Erikson, J.R.; Ross, R.J. ´´Nondestructive assessment of single-span timber bridges using a vibration-based method´´. USDA Forest Service, Research Paper FPL-RP-627. Forest Products Laboratory, June 2005. 17 p. 2005a.
(18) Wang, X.; Wacker, J.P.; Ross, R.J.; Brashaw, B.K.; Vatalaro, R. “Development of fl exural vibration inspection techniques to rapidly assess the structural health of timber bridges systems.” Proceedings of the 14th International Symposium on Nondestructive Testing of Wood. Hannover, 2 - 4 May 2005. Published by Shaker Verlag, Germany, (2005b), pp. 113 - 121.
(19) Crews, K.; Samali, B.; Li, J. “Reliable assessment of aged timber bridges using dynamic procedures.” Proceedings of the 8th World Conference on Timber Engineering. 14 -17 June 2004. Lahti, Finland. Vol II. (2004a), pp. 295 - 300.
(20) Crews, K.; Samali, B.; Li, J.; Bakoss, S.; Champion, C. “Testing and assessment procedures to facilitate the management of timber bridge assets.” Proceedings of the 3rd CECAR - Civil Engineering Conference in the Asian Region. Seoul, Korea. 16 -19 August 2004. (2004b). 15 p.
(21) Ross, R.J.; Hunt, M.O.; Wang, X.; Soltis, L.A. “Floor vibration: a possible assessment method for historic buildings.” APT Bulletin, The Journal of Preserv. Technology. Vol. XXII, 2-3 (2001), pp. 23- 25.
(22) UNE-EN 13183-2: 2002. Contenido de humedad de una pieza de madera aserrada. Parte 2: Estimación por el método de la resistencia eléctrica.
(23) UNE-EN 408: 2004. Estructuras de madera. Madera aserrada y madera laminada encolada para uso estructural. Determinación de algunas propiedades físicas y mecánicas.
(24) Divos, F. “Portable Lumber Grader.” 13th International Symposium on Non-destructive Testing of Wood. Berkeley, California, USA 2002 August 19-21. (2002).
(25) UNE-EN 338: 2003. Madera aserrada estructural. Clases resistentes.
(26) UNE-EN 384: 2004. Madera estructural. Determinación de los valores característicos de las propiedades mecánicas y la densidad.
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