Jānis Šliseris

Optimization of multispan ribbed plywood plate macrostructure for multiple load cases

AbstractThis paper discusses an optimized structural plate of plywood composite that consists of top and bottom plywood flanges and a core of plywood ribs. The objective function is structures weight. Typical constrains – maximal stress criteria and maximal deformation criteria – are used. The optimization is done by Genetic Algorithm (GA), and optimization results are used to train Feed-Forward Artificial Neural Network. The numerical simulation of plywood structure is done by using classical linear Kirchoff–Love theory of multilayer plate and Finite Element Method. As a result, an effective optimization methodology for plywood composite material is proposed. The most rational (according to strength-stiffness criteria) plywood composite macrostructure is obtained for some typical cases.

Experimental and Numerical Investigation of Plywood Panel with Curved Ribs

Abstract Numerical and experimental investigations of plywood unbalanced sheets and plywood panel with curved ribs are done. The moisture diffusion coefficient and deformability of special type of unbalanced sheet that might be used in manufacturing of curved ribs are studied. Results show that rational time of thermal treatment is 2.5-3 hoursand temperature are proposed to provide a shape stability of plywood elements. The behaviour of small scale experimental model of three hinged triangular roof structure that is made of plywood panels with curved ribs is experimentally studied.

Glued Joint Behavior of Ribs for Wood-Based Composite Plates

This article presents experimental investigations of composite sandwich plywood plates with cell type core and their connections between skin layers of birch plywood and a core of straight and curved plywood honeycomb-type ribs. This shape of core ribs provides several improvements for these plates in the manufacturing process as well as improves the mechanical properties of plywood plates. This specific form of ribs allows simplifying the manufacturing of these plates although it should be detailed and improved. The most typical cases (series of specimens) were compared to the results obtained from FEM (ANSYS) simulations. All thicknesses of elements are chosen according to plywood supplier assortment. Standard birch plywood (Riga Ply) plates were used - three layer plywood was chosen for skin elements (Surfaces) and three or five layer plywood was chosen for edge elements. Different bond pressures were taken to compare their influence on joint strength and stiffness.