engleski

3D analysis of stress distribution in veneer plywood under bending load

In the paper, an analysis is conducted of all six stress components and all six strain components, for the purpose of determining the importance of individual stress components that occur in veneer plywood under bending load. A 3D analysis was conducted using the finite element method, statics module - linear elastic theory. Two numerical models were created in line with the test method (EN 310) for determining the bending properties of veneer plywood. One model was created such that the load direction is parallel to the face grain direction, and the other when the load direction is perpendicular to the face grain direction. The results shown include the distribution of stress along the plywood surface, as well as the stress distribution in individual layers, i.e. by plywood thickness. The stress results relate to the direction of the axis in the global Cartesian coordinate system. The highest values are seen with normal stress, in particular the component σ x which has a direction parallel to the load direction. In shear strain, the highest values are seen in the component τ xz. The value of σ x varies stepwise linearly, through the thickness of the veneer plywood, which is the direct result of the cross-orientation of individual layers. Unlike σ x, the value of the strain component τ xz continually increases linearly from the lower to the upper layer. The component τ xz also characterises the greatest increase in shear strain values. Though the remaining components of normal strain σ y and σ z, and shear strain τ xy and τ yz are substantially lower, they are also very important in analysing the stress of plywood, as they cause significant strain in the veneer.

plywood; bending; stress; finite element method; three dimensions

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