This research was performed in order to determine how the heating process affects the mechanical properties of pine and spruce wood. Studies were carried out using wood heated in laboratory. The measurements of specimens were 250x20x6mm. Specimens were divided into the following three groups: specimens of one group were not exposed to heating, whereas specimens of two other groups were subjected to heating at the temperature of 190○C and 215○C, in the air under atmospheric pressure. Before and after heat treatment the mechanical properties of specimens were assessed using the method of transverse vibrations. Then specimens, heated at the different temperatures, were bonded together using cold press and the mechanical properties were observed again. The results showed a slightly increase of MOE of all specimens, from 1,9% to 5,5% of spruce wood and from 1,7% to 6,9% of pine wood. Moreover, the increase of density were 4,4 – 7,1% for spruce wood and 1,0 – 2,6% for pine wood. The highest results of MOE after gluing showed non-treated pine specimens and spruce specimens, treated at 190○C and 215○C. Wood equilibrium moisture content after treatment is reduced and it is known, that the drier the wood – the better it’s mechanical properties.
Keywords: heat-treatment, non-destructive evaluation, MOE, mechanical properties
Authors
Navickas P.
Department of materials engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Lithuania
Albrektas D.
Department of materials engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Lithuania
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