Affiliation:
1. Department of Wood Science and Wood Protection, Institute of Wood Sciences and Furniture, Warsaw University of Life Science – SGGW, Warsaw, Poland
2. Faculty of Wood Technology, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
Abstract
The influence of loading speed on the bending strength of beech (Fagus sp.) and birch (Betula sp.) wood The subject of this paper was to investigate the effect of loading speeds from 20 mmˑmin-1 to 200 mmˑmin-1 on the flexural strength and deformation of beech (Fagus sp.) and birch (Betula sp.) wood with moisture content close to the absolutely dry state and fibre saturation point. A GOM Aramis measuring system, operating with Digital Image Correlation (DIC) technology, was used in the study to record the displacement and deformation of the elements in real time. The results obtained for flexural strength, flexural modulus and the amount of deformation observed showed a relationship between material properties and loading rate. At higher moisture content, the bending strength and modulus of elasticity decreased with increasing deflexion. The highest bending strength and modulus of elasticity were achieved by the tested wood species at a loading rate of 200 mmˑmin-1. Beech wood, compared to birch wood, showed higher bending strength and modulus of elasticity. Images obtained by means of DIC revealed, at moisture contents close to the dry state, a symmetrical distribution of compressive and tensile stresses relative to the neutral axis of the sample cross-section. At higher moisture contents, there was a significant asymmetry between the compressive and tensile stresses and an apparent shift of the neutral axis towards the tensile surface.
Reference18 articles.
1. BÜYÜKSARI, Ü. (2017). Effect of Loading Rate on Mechanical Propertiesof Micro-size Scots Pine Wood, BioResources 12(2), 2721-273010.15376/biores.12.2.2721-2730
2. DOBROWOLSKA, E., LICHACZEWSKA, B., & PINCHEVSKA, O. (2020). Theimpact of crosshead speed on the strength of spruce wood (Picea abies L.). Annals ofWarsaw University of Life Sciences-SGGW. Forestry and Wood Technology, (109)
3. FUCHS, F. R. (1963). Untersuchungen über den Einfluss von Temperatur undHolzfeuchtigkeit auf die elastischen und plastischen Formänderungen von Buchenholzbei Zug- und Druckbelastung. Diss. UNI Hamburg.
4. 1724. HÄNSEL, A. (2012). Holz und Holwerkstoffe. Prüfung-Struktur-Eigenschaften. Berlin.
5. HÄNSEL, A. (2012). Holz und Holwerkstoffe. Prüfung-Struktur-Eigenschaften. Berlin. Logos Verlag