Impact of Veneer Layouts on Plywood Tensile Strength

Abstract

The aim of the research presented in this paper is to study the plywood tensile strength through a change of the position of layers in the panel structure around the central axis, without changing the number and thickness of veneers. So far, it has been known that the veneer layout in plywood structure has a signifi cant impact on plywood bending properties. Besides these mechanical properties, the tensile strength of plywood is also a property that can defi ne the use of plywood as a structural or non-structural panel. For studying the impact of veneer layout on plywpood tensile strength, experimental models of nine-layer plywood were made. The models were made from peeled beech veneer with the thickness of 1.2, 1.5, 2.2 and 3.2 mm. The modelling was performed on the basis of changing the position of veneer, 3.2 mm thick, around the central axis. Pure water-soluble phenol-formaldehyde resin was used as plywood binder. The tensile strength of plywood panels was tested in fi ve directions: parallel and perpendicular to the face grain, as well as at the angle of 22.5°, 45° and 67.5° to the face grain of the plywood panel. On the basis of the obtained data for tensile strength in different directions of plywood panel, the coeffi cient of equality of tensile strength of plywood models was calculated (K et). The coeffi cient of mass quality (K mq) was calculated, too. The research results showed that different veneer layouts in plywood structure have a signifi cant impact on plyood tensile strength. All tested plywood models meet the defi ned values of tensile strength in accordance with the requirements of the national (МКС) standard for structural plywood for use in construction. Different layouts of veneer sheets in panel structure give opportunities for production of panels with different strength characteristics.

Influence of the number of layers on the strength of beech laminated elements in the three-point flexural test,

“…They discovered that materials with higher thickness must be used to increase the attenuation rate of deflection. Popovska et al (2017) investigated laminated wood modified with carbon polymer or carbon fabric. The tensile-shear strength values were compared to non-reinforced wood and polyurethane, and epoxide adhesives were used in their experiment.…”

Stress and Strain Analysis of Plywood Seat Shell

“…The possibility of applying computer programs for the evaluation of mechanical properties of laminated wood and choosing the optimal material for product development is demonstrated by Brezović et al (2018). The results of experimental analysis of plywood tensile strength through a change of the position of layers in the panel structure around the central axis show that different veneer layouts in plywood structure have a remarkable impact on plywood tensile strength (Jakimovska Popovska, et al, 2017). Numerical methods, such as the 'fi nite element method', are applicable and effective for the analysis of laminated wood, and the numerical results depend on simplifi cations and assumptions introduced in the numerical model.…”

Dimensional and Shape Stability of Plywood Seat

“…The investigations in this domain of wood constructions are focused primarily on the analysis of mechanical properties of plywood. Different veneer layouts in plywood structure have a remarkable impact on plywood tensile strength [1]. Investigation of veneer layouts impact on strength of laminated wood and evaluation of mechanical properties of laminated wood was analysed by computer programs [2] and [3].…”