Formänderungen in Holzquerschnitten

The Relationship of Structure to Transverse Anisotropy in Wood with Reference to Shrinkage and Elasticity

“…it can be readily asccrtaincd that EU < ET From the above argumentation it is evident that the author does not subscribe to Keylwerth's postulation that ßtlßr = E n /E T (29), though a relationship between the two ratios can be acknowledged. In whole wood the annual ring structure, for instance, will have opposite effects on ßt/ßr and / .…”

“…The relation has been investigated by Keylwerth (29). <> In the following, arguments and evidence from the authpr's experiments is given for the existence of this relation in homogeneous tissue, but at the same time it is indicated that the relation may be weak or even not existing in whole wood (composite tissue).…”

“…An unknown factor, moreover, is the degree to which the cell deformations caused by drying Stresses should be regarded äs elastic or äs plastic. Keylwerth (29) postulates that the deformations are plastic. He found, moreover, that at comparable load levels, the ratio of tangential to radial deformations is the same in the plastic äs in the elastic ränge.…”

Wechselwirkung zwischen der Anisotropie der Schwind- und Quellmaße sowie Holzfeuchte-Änderungen in der Ebene von gekrümmtem Brettschichtholz

“…Das Verhältnis gilt ebenso für die Schwindmaße in tangentialer (β t ) und in radialer Richtung (β r ). Diese Erkenntnisse gehen unter anderem auf grundlegende Betrachtungen und Untersuchungen von Keylwerth (1951Keylwerth ( und 1962 zurück. …”

“…Hauptrichtungen folgen (Keylwerth 1951); umgekehrt gilt, dass sich Querschnittskanten beim Schwinden um so mehr krümmen und verzerren, je mehr sie von den Hauptrichtungen abweichen (Kollmann 1981). In diesem Sinne gab Keylwerth (1944Keylwerth ( /1945 …”