Plywood is one of the earliest produced engineered wood products (EWP). It consists of an uneven number of thin veneers, glued together with the grain direction of adjacent veneers perpendicular to the one another (Sellers 1985). Due to its cross-laminated configuration, plywood exhibits more homogenous mechanical properties than solid wood, making it suitable for versatile connection applications that are subjected to multiple types of stresses in multiple directions, e.g. in roof (Turnbull 1986; del Coz Díaz et al. 2013) and beam-column (Furuheim and Nesse 2020) connections. In order to optimise the structural design and analyse the mechanics of the plywood application, the first step is to gain knowledge regarding the mechanical properties of plywood at varying angles to the grain. However, limited information on such properties are available in literature, especially for birch plywood (Norris 1950; Bier 1984). In this study, birch (Betula pendula and Betula pubescens) is utilized as raw material, assigning high density, stiffness and strength to plywood. The tensile strength of birch plywood at varying angles (0-90 degree) to the face grain is predicted analytically by using linear and quadratic failure criteria. Experimental tests will be carried out in the future to provide a database of such mechanical properties and determine the applicability of each failure criterion for birch plywood.
Keywords: tensile strength, birch plywood, mechanical properties
Authors
Tianxiang Wang
Yue Wang
Roberto Crocetti
Magnus Wålinder
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