Visko‐elastisches Verhalten von Holz‐Klebstoff‐Verbindungen unter zyklischer Zug‐Druck‐Belastung

Visco‐elastic behavior of bonded wood under cyclic tensile and compression loading In the present contribution, a test method is used to simulate the static, cyclic loading of adhesive joints due to swelling and shrinking of the wood and to demonstrate the plastic deformation in the low load range. For tensile shear specimens prepared from beech wood and bonded with three different adhesives (MUF, PRF, PUR), the elastic behavior under cyclic tensile and compression loading was investigated and the loss and storage of energy was determined. All tested adhesives showed viscose parts even at a very low load level of 3 MPa. At a load level of 7 MPa, the PRF joints revealed a more elastic behavior than the other. The increased loss energy determined for the PUR bonding indicates a softening of the adhesive joint.     

Diagramme zur Auswertung der Johansen‐Formeln für einschnittige Holz‐ bzw. Holzwerkstoff‐Verbindungen

Diagrams to evaluate the Johansen‐formulas for single shear connections of timber or wood‐based panels. Metal dowel‐type fasteners are nowadays designed by using the Europe‐wide applied, but rather complex Johansen Theory, which is effectively used by means of computer programs. This however can yield a diminished overview. In this contribution the evaluation is done by use of diagrams, which should facilitate the application of the new design rules in addition or as an alternative to other methods.