Abstract
An engineering method is presented for the analysis of creep deformation in wood due to changing moisture content. The method is applied to the analysis of stresses in timber during long-term loading. It is concluded that the larger variation of moisture content at the surface layer of timber makes its creep rate higher than in the middle of the cross-section. As a result, an increasing portion of the load will be carried by the inner part of the material during sustained loading. This uneven stress distribution may explain to a great extent why the strength of wood is lower under a long-term load than under a short-term load.
Zusammenfassung
Eine Methode zur Analyse der Kriechverformung während Feuchteveränderungen wird vorgestellt. Die Methode wird angewandt zum Bestimmen der Spannung unter Langzeitbelastung. Die stärkere Änderung der Holzfeuchte an der Oberfläche führt dort zu einer höheren Kriechverformung als im Innern des Querschnittes. Daraus ergibt sich eine erhöhte Belastung der inneren Probenteile während der Belastungsversuche. Diese ungleichmäßige Spannungsverteilung kann zu einem großen Teil erklären, warum die Holzfestigkeit unter Langzeitbelastung geringer ist als unter kürzerer Belastung.
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Ranta-Maunus, A. Impact of mechano-sorptive creep to the long-term strength of timber. Holz als Roh-und Werkstoff 48, 67–71 (1990). https://doi.org/10.1007/BF02610709
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DOI: https://doi.org/10.1007/BF02610709