Polyurethane-solid wood composites. II. Flammability parameters

2009 ◽  
Vol 113 (5) ◽  
pp. 3279-3285 ◽  
Author(s):  
Zhenhua Gao ◽  
Wenqiang Su ◽  
Di Wu
Keyword(s):  
Solid Wood ◽  
Wood Composites ◽  
Flammability Parameters

Mode III fracture energy of wood composites in comparison to solid wood

1999 ◽  
Vol 33 (5) ◽  
pp. 391-405 ◽  
Author(s):  
R. J. A. Ehart ◽  
S. E. Stanzl-Tschegg ◽  
E. K. Tschegg
Keyword(s):  
Fracture Energy ◽  
Solid Wood ◽  
Wood Composites ◽  
Mode Iii

scholarly journals The Influence of Thickness on the Tensile Strength of Finnish Birch Veneers under Varying Load Angles

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Maximilian Pramreiter ◽  
Alexander Stadlmann ◽  
Christian Huber ◽  
Johannes Konnerth ◽  
Peter Halbauer ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Size Effect ◽  
High Performance ◽  
Mechanical Performance ◽  
Solid Wood ◽  
Strengthening Effect ◽  
Wood Composites ◽  
Design Flexibility ◽  
Wood Part ◽  
Load Angle

The development of high-performance, veneer-based wood composites is a topic of increasing importance due to the high design flexibility and the comparable mechanical performance to solid wood. Part of this improved mechanical performance can be contributed to the size effect present in wood. Based on previous findings in the literature, this size effect can be either strengthening or weakening. The presented study investigates the influence of thickness and load angle on the tensile strength and tensile stiffness of peeled veneers compared to thin sawn timber. Veneers with thicknesses of 0.5 ± 0.05 mm, 1.0 ± 0.05 mm and 1.5 ± 0.05 mm as well as sawn wood with thicknesses of 1.5 ± 0.1 mm, 3.0 ± 0.1 mm and 5.0 ± 0.1 mm were tested in tension under different load angles (0°, 45° and 90°). The results only partly confirm a size effect for strength parallel to the grain. The strength perpendicular to the grain increased significantly between 0.5 mm and 1.5 mm, with a significant decrease between 1.5 mm and 5.0 mm. The presence of lathe checks diminished the strength perpendicular to the grain of the veneers by about 70% compared to solid wood, partly overshadowing a possible strengthening effect. It was concluded that a transition from a strengthening to a weakening behaviour lies in the range of multiple millimetres, but further investigations are needed to quantify this zone more precisely. The presented results provide a useful basis for the development of veneer-based wood composites with a performance driven layer-thickness.

BIODEGRADATION BEHAVIOR OF POLY(VINYL ALCOHOL) - WOOD COMPOSITES

2019 ◽  
Vol 18 (1) ◽  
pp. 125-136 ◽  
Author(s):  
Luiza Jecu ◽  
Iuliana Raut ◽  
Elena Grosu ◽  
Mariana Calin ◽  
Violeta Purcar ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Wood Composites

Untersuchungen zum Diffusionswiderstand von Holzwerkstoffen | Diffusion resistance of timber materials

2005 ◽  
Vol 156 (3-4) ◽  
pp. 100-103
Author(s):  
Rudolf Popper ◽  
Peter Niemz ◽  
Gerhild Eberle
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Middle Lamella ◽  
Solid Wood ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Wood Panels ◽  
Vapour Diffusion ◽  
Wet Climate ◽  
Panel Thickness

The water vapour diffusion resistance of timber materials were tested in a wet climate (relative humidity ranging from 100%to 65% at 20 °C) and in a dry climate (relative humidity ranging from 0% to 65% and from 0% to 35% at 20 °c) with variation by relative humidity and vapour pressure gradient. The diffusion resistance of multilayer solid wood panels lies under or within the range of the solid wood (spruce), tending even to a lower range. This can be attributed to the loosely inserted middle lamella of the used solid wood panels, which were not correctly glued by the manufacturer. The diffusion resistance of the solid wood panels increases with decreasing moisture content and decreasing panel thickness, as well as with increasing water vapour gradient from 818 to 1520 Pa. There were clear differences between the tested timber materials. The diffusion resistance of particle composites is strongly dependent on the specific gravity. Due to laminar particles OSBs(Oriented Strand Boards) have a larger diffusion resistance than chipboards. The water vapour diffusion resistance of OSBs lies within the range of plywood.

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