Nondestructive characterization of wood by monitoring of local elastic anisotropy and dynamic nonlinearity
-
Abstract
The results of non-contact measurements of local in-plane elastic anisotropy in wood by monitoring the flexural plate wave velocity as a function of azimuth angle of propagation are reported. The Focused Slanted Transmission of air-coupled ultrasound is used to generate and detect locally the flexural waves in wood as well as to measure their velocities. The analysis presented shows that for thin plates the flexural wave velocity can be readily used to evaluate the anisotropy of Young’s modulus. This conclusion is confirmed by measurements of the plate wave anisotropy factors for veneer laminae and cross-ply laminates of spruce and beech. The technique is sensitive enough to detect the anisotropy variation of earlywood caused by the incorporation of latewood areas in growth rings. A new approach based on dynamic nonlinearity of wood is developed and applied to acoustic imaging of wood structure and detecting of defects in wood. The hysteresis mechanism of the dynamic nonlinearity is shown to dominate in clear wood and to manifest in a primary generation of odd acoustic harmonics. Local maxima of the odd higher harmonic amplitudes in the LR- and LT-planes of softwood are observed in the earlywood area close to latewood/earlywood transition interface that indicates the lower stiffness and strength of wood in those areas. The higher-order even harmonics and subharmonics in the nonlinear vibration spectra of wood are mostly produced by “clapping” in defect areas. Measurements of local amplitudes of these modes are applied to nonlinear acoustic imaging of cracks, delaminations and knots in wood and wood composites.
References
Achenbach, J.D. Wave Propagation in Elastic Solids. North-Holland Publishing Company, Amsterdam, 1973.Suche in Google Scholar
Agarwal, B.D., Broutman, L.J. Analysis and Performance of Fiber Composites. John Wiley & Sons, Inc., New York, 1990.Suche in Google Scholar
Bodig, J., Jayne, B.A. Mechanics of Wood and Wood Composites. Van Nostrand Reinhold Company, New York, 1982.Suche in Google Scholar
Bucur, V. Acoustics of Wood. CRC Press, Boca Raton, 1995.Suche in Google Scholar
Bucur, V. and Rasolofosaon, P.N.J. (1998) Dynamic elastic anisotropy and nonlinearity in wood and rock. Ultrasonics38:813–824.10.1016/S0041-624X(98)00004-3Suche in Google Scholar
Bucur, V. Nondestructive Characterization and Imaging of Wood. Springer-Verlag, Berlin Heidelberg, 2003.10.1007/978-3-662-08986-6Suche in Google Scholar
Briggs, A. Acoustic Microscopy. Clarendon Press, Oxford, 1992.10.1088/0034-4885/55/7/001Suche in Google Scholar
Cremer, L. (1947) Über die Analogie zwischen Einfallswinkel und Frequenzproblemen. Arch. Electr. Übertragung1: 28.Suche in Google Scholar
Haberger, C.C., Mann, R.W., Baum, G.A. (1979) Ultrasonic plate waves in paper. Ultrasonics17:57–62.10.1016/0041-624X(79)90096-9Suche in Google Scholar
Hearmon, R.F.S. (1948) The elasticity of wood and plywood. Forest Products Res. Spec. Report. No. 7, His Majesty’s Stationery Office, London.Suche in Google Scholar
Luukkala, M., Heikkili, P., Surakka, J. (1971) Plate wave resonance – a contactless method. Ultrasonics9:201–208.10.1016/0041-624X(71)90387-8Suche in Google Scholar
Solodov, I., Krohn, N., Busse, G. (2002) CAN: an example of non-classical acoustic nonlinearity in solids. Ultrasonics40:621–625.10.1016/S0041-624X(02)00186-5Suche in Google Scholar
Solodov, I., Pfleiderer, K., Gerhard, H., Predak, S., Busse, G. (2004) Slanted transmission mode of air-coupled ultrasound: new opportunities in NDT and material characterisation. In: Emerging Technologies in Non Destructive Testing. Eds. Van Hemelrijck, Anastasopoulos, Melanitis. Swets & Zeitlinger, Lisse. pp. 107–112.Suche in Google Scholar
Zheng, Y., Maev, R., Solodov, I. (1999) Nonlinear acoustic applications for material characterization: A review. Can. J. Phys.77:927–967.10.1139/cjp-77-12-927Suche in Google Scholar
© Walter de Gruyter
Artikel in diesem Heft
- The effects of initial spacing on wood density, fibre and pulp properties in jack pine (Pinus banksiana Lamb.)
- An improved procedure for isolation of residual lignins from hardwood kraft pulps
- Small angle scattering in the Porod region from hydrated paper sheets at varying humidities
- Application of confocal Raman spectroscopy for the topochemical distribution of lignin and cellulose in plant cell walls of beech wood (Fagus sylvatica L.) compared to UV microspectrophotometry
- UV-microscopic analysis of acetylated spruce and birch cell walls
- On-line study of lignin behaviour in dilute alkaline solution by the SEC-UV method
- Extracellular diffusion pathway for heartwood substances in Albizia julibrissin Durazz.
- New glucosides from Eucalyptus globulus wood, bark and kraft pulps
- Nondestructive characterization of wood by monitoring of local elastic anisotropy and dynamic nonlinearity
- Chemical reaction of maritime pine sapwood (Pinus pinaster Soland) with alkoxysilane molecules: A study of chemical pathways
- Thermal forming of chemically modified wood to make high-performance plastic-like wood composites
- Eco-composite from poly(lactic acid) and bamboo fiber
- Bamboo fiber (BF)-filled poly(butylenes succinate) bio-composite – Effect of BF-e-MA on the properties and crystallization kinetics
- Dimensional changes in Corsican pine (Pinus nigra Arnold) modified with acetic anhydride measured using a helium pycnometer
- Microwave-enhanced release of formaldehyde from plywood
- Artificial weathering of tropical woods. Part 1: Changes in wettability
- Artificial weathering of tropical woods. Part 2: Color change
- Inhibition of fungal degradation of wood by 2-hydroxypyridine-N-oxide
- Microwave treatment to accelerate fixation of copper-ethanolamine (Cu-EA) treated wood
Artikel in diesem Heft
- The effects of initial spacing on wood density, fibre and pulp properties in jack pine (Pinus banksiana Lamb.)
- An improved procedure for isolation of residual lignins from hardwood kraft pulps
- Small angle scattering in the Porod region from hydrated paper sheets at varying humidities
- Application of confocal Raman spectroscopy for the topochemical distribution of lignin and cellulose in plant cell walls of beech wood (Fagus sylvatica L.) compared to UV microspectrophotometry
- UV-microscopic analysis of acetylated spruce and birch cell walls
- On-line study of lignin behaviour in dilute alkaline solution by the SEC-UV method
- Extracellular diffusion pathway for heartwood substances in Albizia julibrissin Durazz.
- New glucosides from Eucalyptus globulus wood, bark and kraft pulps
- Nondestructive characterization of wood by monitoring of local elastic anisotropy and dynamic nonlinearity
- Chemical reaction of maritime pine sapwood (Pinus pinaster Soland) with alkoxysilane molecules: A study of chemical pathways
- Thermal forming of chemically modified wood to make high-performance plastic-like wood composites
- Eco-composite from poly(lactic acid) and bamboo fiber
- Bamboo fiber (BF)-filled poly(butylenes succinate) bio-composite – Effect of BF-e-MA on the properties and crystallization kinetics
- Dimensional changes in Corsican pine (Pinus nigra Arnold) modified with acetic anhydride measured using a helium pycnometer
- Microwave-enhanced release of formaldehyde from plywood
- Artificial weathering of tropical woods. Part 1: Changes in wettability
- Artificial weathering of tropical woods. Part 2: Color change
- Inhibition of fungal degradation of wood by 2-hydroxypyridine-N-oxide
- Microwave treatment to accelerate fixation of copper-ethanolamine (Cu-EA) treated wood
