Numerical simulation of hot-pressed veneer products
2007 (English)Report (Other academic)
Customers demand very high quality of veneered furniture products with regard to surface appearance, shape stability and stiffness. To meet these requirements, it is important to improve the manufacturing process by a better understanding of the thermo-hygro-mechanical behaviour of the individual veneers. During the manufacture of strongly curved products, the veneers are exposed to large membrane and bending deformations and to high pressure in the radial fibre direction. When hot-press forming is used, the veneers are also exposed to a high surface temperature during the pressing time (curing time). These severe conditions can result in plastic deformation perpendicular to the veneer surface as well as mechano-sorptive strains in the curved regions, since the heating can have a significant influence on the moisture distribution. How strong an influence these factors have on the distortion of the veneered product and on the final surface quality (i.e. grain-raising and fissuring) of the product is far from being fully clarified. To study this complex multi-physical problem including temperature, moisture, large deformations for orthotropic materials, surface constraints and progressive glue interaction, a three-dimensional finite element model has been developed. In this study, the simulation of deformations and stresses occurring during the manufacture of a curved veneered product (chair seat) of birch wood is described. The results show that heating, pressure and the fibre orientation in the veneers have a significant influence on the distortion of the chair seat. The model can also be used to study the risk of fracture in the veneers and in the glue line.
Place, publisher, year, edition, pages
Växjö: Växjö universitet, Teknik & design , 2007. , 14 p.
, Working paper, TD, 2007:19
FEM, furniture, twist, thermo-hygro-mechanical behaviour, manufacturing, fibre orientation, mechano-sorption, birch
formpressning, skiktlimning, faner, trä, formstabilitet, bok, björk, finitelement
Research subject Technology (byts ev till Engineering), Forestry and Wood Technology
IdentifiersURN: urn:nbn:se:lnu:diva-21015OAI: oai:DiVA.org:lnu-21015DiVA: diva2:543159