Effects of ply grading and assembly on the properties of plywood panels from Pinus merkusii

Abstract

This study aims to manufacture plywood panels with both graded plies (by visual and acoustic wave methods) and ungraded plies (randomly selected), bonded together in different arrangements, and also to verify the effect of these techniques on the specific mass, strength and stiffness against static bending and binding strength of finished panels. Plywood panels manufactured exclusively with superior quality plies, as graded by the acoustic wave method, and plywood panels manufactured exclusively with randomly selected plies had better performance, with no significant differences being noted between them, except for specific mass.Key words: Ply grading, nondestructive testing, acoustic wave method. EFEITOS DA CLASSIFICAÇÃO E MONTAGEM DE LÂMINAS SOBRE AS PROPRIEDADES DE COMPENSADOS DE

Effect of Nondestructive Evaluation of Veneers on the Properties of Laminated Veneer Lumber (LVL) from a Tropical Species

“…Therefore, LVL made based on the stiffness grade presented better mechanical properties. Nevertheless, Bortoletto Jr. [13] found different results, and plywood assembled with randomly or pre-graded Pinus merkusii veneers presented similar bending and shear properties. Table 3 presents the mathematical models fitted to predict flexural properties of the boards using stress wave variables of veneers and boards.…”

“…Wang et al [15], while studying ultrasonically (US) rated veneer from red maple, found a positive relationship between veneer US variables and LVL billet stiffness and strength. Bortoletto [13] on the other hand did not find any effect on the properties when plywood was manufactured using randomly or ultrasonically rated veneers from Pinus merkusii. Teles et al [12] found that lumber nondestructively tested by means of transverse vibration yielded stronger and stiffer glulam beams made from a tropical hardwood (Sextonia rubra).…”

“…Visual and acoustic nondestructive methods have been used previously to sort logs, lumber and veneers employed in the manufacturing of ply-based wood composites, as seen in several works [10][11][12][13][14][15]. Wang et al [15], while studying ultrasonically (US) rated veneer from red maple, found a positive relationship between veneer US variables and LVL billet stiffness and strength.…”