| Popis: |
The paper presents the results of the research of the bending modulus of elasticity of some 700 year old subfossil elm wood (Ulmus minor) retrieved from the Sava riverbed (Bosnia and Herzegovina). The subfossil elm wood is very rare to find and is highly appreciated in this form for its beautiful appearance and specific mechanical properties. Adult elm trees are nowadays also very scarce in natural forest stands of SE Europe, due to the invasion of the Dutch elm disease (Ophiostoma novo-ulmi Brasier) some fifty years ago. The bending MOE was determined in the longitudinal direction and the angles between the direction of load and the annual growth ring orientation were 0°, 45°, and 90°. The obtained values of the bending modulus of elasticity are within the range of those obtained for a recent elm, which shows that numerous centuries spent in anoxic aquatic conditions have not affected the investigated property of subfossil elm. The study showed that the annual growth ring orientation significantly affects the MOE of subfossil elm wood in the longitudinal direction. The highest values were obtained at the angle of 45° (L45°), and the values for L0° and L90° are very similar. The variability and heterogeneity of the MOE was described with the two-parameter Weibull distribution and the results follow the Weibull distribution. |
