THE USE OF NON-DESTRUCTIVE STRESS WAVE TECHNIQUE FOR WOOD VENEER CLASSIFICATION AND STRUCTURAL LAMINATED VENEER LUMBER PRODUCTION

摘要

This research had as objective the viability study of laminated veneer lumber structural panels (LVL) production from Pinus taeda L. wood, through veneers preliminary classification, in quality grades, by stress wave non-destructive method. Rotary cut veneers with 3,2 and 4,2mm thick were obtained from 2,60m logs, from 59 trees of a 21 years old Pinus taeda, located in Rio Negrinho-SC. After drying a non-destructive evaluation of the veneers quality were made by stress wave. The individual dynamic modulus of elasticity (MOEd) was determined and the veneers classified in quality grades. Forty-eight (48) LVL panels with average thickness of 28mm and nominal dimension of 1,22m x 2,44m were produced. The static bending strength properties from the panels were evaluated, modulus of rupture (MOR), modulus of elasticity (MOE) and stress at the proportional limit (SPL). Results showed higher average values of modulus of elasticity (MOE) 11%, modulus of rupture (MOR) 23% and stress in the proportional limit (SPL) 13%, from panels produced with preliminary classified veneers by the dynamic modulus of elasticity when compared with LVL panels made with non classified veneers. In conclusion results demonstrate the technical viability of structural LVL panels production with high strength properties starting from classified veneers of Pinus taeda L.