Compression wood in softwood is often considered as an inconvenience for structural applications, saw and paper milling, since it affects the end product negatively. However, it serves a mechanical function in green state, e.g. in supporting tree branches. These features found in softwood branches can be an example for improving bending strength in engineered composite materials. The maximum bending moment of a branch can be increased significantly solely through the presence of compression wood. This is note-worthy, since chemical components of the compression wood do just differ slightly from the normal wood. The tissue gradients in the branch resulting from variation in density, microfibrillar angle and cell geometry contribute to the strength improvements. In this work, we have investigated the mechanical implications of structural and chemical changes in softwood branches through a model based on Euler-Bernoulli beam bending.
Keywords: compression wood, Euler-Bernoul-li beam bending, composite beam
Authors
Marie Hartwig
Uppsala University, Lägerhyddsvägen 1, 752 37 Uppsala, Sweden
Kristofer E. Gamstedt
Malin Wohlert
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