engleski

Modulus of elasticity of subfossil elm wood

The aim of this study was to determine the longitudinal Modulus of elasticity (MOE) of subfossil elm. The study was carried out on a sample of almost 700 years old wood retrieved from the bed of the river Sava (north Bosnia). The elm is very scarce as subfossil wood and it is highly appreciated in this form for its beautiful appearance and specific mechanical properties. Elm trees are nowadays extremely rare also in natural forest stands of SE Europe because of the invasion of Dutch elm disease some fifty years ago. The longitudinal modulus of elasticity was determined by the tree-point bending test. The direction of the load in relation to the orientation of annual growth rings was 45°. The results are compared with the MOE values from the available literature and this comparison showed that the values for subfossil elm are in the range found in literature data for recent elm. This indicates that the anoxic fluvial environment that surrounded the wood for 700 years has not significantly affected its MOE. The variability and heterogeneity of the MOE was described with the two-parameter Weibull distribution, which shows great goodness of fit.

bending modulus of elasticity, subfossil elm wood, annual growth ring orientation, Weibull distribution

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