engleski

Effects of microstructural orientation on bending strength in the longitudinal direction of peduculate oak

Wood is a natural building material that is heterogeneous and anisotropic structure and therefore has different properties. The properties may vary depending on the species, but also the anatomical structure of the trees within the species, where they may have ten times lower density in some parts or several times higher bending strength, hardness or stiffness. Bending strength is the resistance of a material to the action of an external force that seeks to bend and break it. For wood, this mechanical property is extremely important, and the value of bending strength depends on the orientation of the wood structure, where the highest value is in the longitudinal direction. For some types of wood, the bending strength also depends on the angle closed by the bending force and annual rings [1, 2]. This study shows the results of testing the bending strength of pedunculate oak (Quercus robur L.) in the longitudinal direction using a three-point bending method. The angle between the bending force and the lines of the annual rings was 0°, 45°, and 90° (Fig. 1). It has been shown that the position of the bending force in relation to the direction of the annual rings slightly affects the value of the bending strength in the longitudinal direction. The highest value of bending strength is obtained for angle 0° (175.30 N/mm2). The values for angles 45° (172.61 N/mm2) and 90° (173.24 N/mm2) are very similar. The dissipation of the results is described with the Weibull distribution, which is confirmed to be suitable for the statistical analysis of the results obtained [3]. For a group of samples with a 45° angle, the value of the Weibull modulus is the highest, indicating the highest homogeneity of the structure.

bending strength, oak, annual ring orientation, Weibull distribution

Konferencija se održala online radi pandemije