Artículos de revistas
Behavior Of Ultrasonic Waves In Wood With Presence Of Holes [comportamento De Ondas De Ultrassom Na Presença De Ocos Na Madeira]
Registro en:
Cerne. , v. 18, n. 3, p. 507 - 514, 2012.
1047760
10.1590/S0104-77602012000300019
2-s2.0-84872954686
Autor
Secco C.B.
Goncalves R.
Cerri D.G.P.
Vasques E.C.
Batista F.A.F.
Institución
Resumen
This work aimed to analyze the pattern of variation in wave lengths in presence of wood holes and to develop a model capable of describing the process. To attain that end, wood pieces were used from species pequiá (Aspidosperma desmanthum), on which circular and linear artificial holes were made and gradually enlarged. Ultrasonic tests were performed using USLab equipment and 45 kHz transducers. Measurements were taken first on the intact piece and then after each stage of artificial hole enlargement. Results demonstrated that propagation velocities of ultrasonic waves are affected by presence of holes and also that reduction in velocity is caused by changes in wave path, since waves tend to deviate from empty space and travel through matter. The circular hole type had a slightly stronger influence on velocity reduction than the linear hole type. Variation in velocity as a function of increasing percentage of hollow space relative to the intact piece can be represented by a linear model. 18 3 507 514 Apolinário, F.E., Martius, C., Ecological role of térmites (Insecta, Isoptera) in tree truncks in central Amazonian rain forests (2004) Forest Ecology and Management, 194, pp. 23-28. , Amsterdam (1997) NBR 7190: Projeto De Estruturas De Madeira, p. 107. , ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS, Rio de Janeiro Bucur, V., (2006) Acoustics of Wood, p. 303. , Berlin: Springer-Verlag Deflorio, G., Fink, S., Schwarze, F.W.M.R., Detection of incipient decay in tree stems with sonic tomography after wounding and fungal inoculation (2007) Wood Science and Technology, 42, pp. 117-132. , New York Lin, C.J., (2008) Application of An Ultrasonic Tomographic Technique For Detecting Defects In Standing Trees, 62, pp. 432-441. , International Biodeterioration & Biodegradation, Birmingham Najafi, S.K., Shalbafan, A., Ebrahimi, G., Internal decay assessment in standing beech trees using ultrasonic velocity measurement (2009) European Journal of Forest Research, 48 (1), pp. 1-6. , Oxford Wang, X., Divos, F., Pilon, C., Brashaw, B.K., Ross, R.J., Pellerin, R.F., (2004) Assessment of Decay In Standing Timber Using Stress Wave Timing Nondestructive Evaluation Tools: A Guide For Use and Interpretation, p. 12. , Washington: USDA, General Technical Report FPL-GTR-147