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Bending and Creep Deformation of a Wood-Based Lightweight Panel: An Experimental Study

Jonaz Nilsson, Jimmy Johansson

Abstract


 

When wood exposed to long-term load, creep deformation can occur, because of its viscoelastic characteristic. The aim of this study was to increase the understanding and knowledge of creep deformation on a wood based lightweight panel of sandwich type, to see if this type of panel had similar properties for creep as solid wood has. This was done through a study based on experiments. The studied panel consisted of two face sheets of beech wood and a core of pine wood struts cross-glued to the face sheets. A solid beech panel was used as a reference. There were in all 27 samples of panel models; the densities of the lightweight panels varied from 165 to 297 kg/m3 compared with the solid panel of 705 kg/m3 density. The study consisted of two parts, a bending test and a creep test. The bending test was used to determine the maximum failure load for the panels. For the creep test, a 30% failure load was used. When the results from the bending tests were ranked to load capacity in relation to density, the results for the lightweight panel varied from 9.0 to 18.0 m4/s2, compared with the value of the reference panel at 27.3 m4/s2. This measured how effective the panel was in withstanding bending loads in relation to density. However, it did not say that the panel with the highest value also took the highest load in absolute terms. If the creep deformation is instead ranked in relation to density, the results for the lightweight panel varied from 10.4 kg/m to 33.7 kg/m. compared with the value of the reference panels at 45.5 kg/m. As with the bending tests, these values show a ranking of how effective the panels are to resist creep deformation in relation to density.

 



Keywords


Lightweight panel, bending, creep, deformation, rupture

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References


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