Evaluation of the Elastic Properties of the Wooden Block
J.Buchar,P. Horácek, L.Severa and L.Slonek Faculty of Forestry and wood science, Mendel University of Agriculture and Forestry Brno, Zemedelska 3, 613 00 Brno, Czech Republic.
ABSTRACT
The paper is focused on the investigation of a possibility to evaluate the elastic parameters of a large wood structure. As a first step the one - dimensional stress wave reflection on the boundary between the bar and the wood block has been studied. The aim of this study consisted in the analysis of the evaluation of wood elastic properties from the incident and reflected elastic wave recorded in the bar. The numerical simulation of the stress pulse propagation in the experimental arrangement described above has been performed. The results of the comprehensive numerical computations suggest that the given arrangement behaves like the two elastic bars in a contact. It is well known that the elastic wave reflected on the boundary between two bars enables to determine the elastic constant in the direction of the bar axis . The numerical results have been verified on the blocks made from different woods (spruce, oak, beech and larch). In the next step the stress wave propagation in the elastic bar connected with the wood cylinder has been studied. This experimental arrangement may be used for a study of elastic properties of living tree. The results of numerical simulations suggests that the wave pattern in the wood cylinder is more complicated than that in the wood block. It means that the evaluation of elastic parameters from the record of the incident and reflected waves in elastic bar must be supported by some numerical computations. An example of this evaluation is presented.
Publication Source: Proceedings of the 12th International Symposium on Nondestructive Testing of Wood University of Western Hungary, Sopron, 13-15 September 2000, ISBN 963 7180 88 5 Publisher: University of Western Hungary, H 9400 Sopron, P.O.Box 132, FAX: +36 99 311 103
