(Example 1)
INFLUENCE OF PLYWOOD STRUCTURE ON COMPRESSIVE
STRENGTH PARALLEL TO THE PLANE OF THE PANEL
Violeta Jakimovska Popovska, Borce Iliev
Ss. Cyril and Methodius University in Skopje, Macedonia,
Faculty of Design and Technologies of Furniture and Interior-Skopje,
e-mail:;
ABSTRACT
Тhe aim of the researches presented in the paper is to study the influence of the changes in plywood structure on plywood compressive strength parallel to the plane of the plywood panel. These changes relate to the change of the position of the layers in the structure of the panel around the central axis, without changing the number and the thickness of the veneers.
For studying this influence, four models of laboratory nine-layered plywood are made. The models are made from peeled beech veneers with thickness of 1,2; 1,5; 2,2 and 3,2 mm.
The modeling is made on the base of the changing of the position of veneers with thickness of 3,2 mm around the central axis (axis of symmetry).
Pure water-soluble phenol-formaldehyde resin is used as plywood binder.
The compressive strength parallel to the plane of the plywood panel is tested in two directions, parallel and perpendicular to the face grain.
The research results showed that all tested models of plywood meet and exceed the defined values of compressive strength in accordance with the requirements of the standard MKS D.C5.043 for structural plywood for use in construction.
Keywords: plywood, veneers, compressive strength, changes, position, layers
(Example 2)
INVESTIGATION OF THE NATURAL FREQUENCIES AND THE
MODE SHAPES OF CIRCULAR SAW WITH COMPENSATING
SLOTS BY THE FINITE ELEMENT METHOD
Georgi Vukov1, Zhivko Gochev1, Valentin Slavov2
1University of Forestry, Faculty of Forest Industry, Sofia, Bulgaria,
e-mail:;
2University of Chemical Technology and Metallurgy,
Faculty of Metallurgy and Material Sciences, Sofia,Bulgaria,
e-mail:
ABSTRACT
This paper shows the methodics and results of the simulative investigation of the circular saw with compensating slots.The investigation is an extension of the previous one done by the authors. The natural frequencies and mode shapes of this kind of circular saws are obtained as results of the investigations. The estimation is done by application programme CosmosWorks.Physical and mechanical properties of the materials are taken into account. The adequate mechanic-mathematical model is used for the aims of the study. The typical characteristics of the structure of this kind of circular saws were taken into account in the model. The circular saw is drawn in 3D by the application programme SolidWorks and it is modeled with four nodes 3D finite elements. The results of this investigation prove the practical significance of the model. They point the possibilities for determinations of resonant regimes and they are basis for their detailed studying.