Influence of veneer lathe checks on the mechanical properties of LVL

Abstract

Laminated veneer lumber (LVL) is a high-performance engineered wood product made of several wood veneers bound together mostly in grain direction. Veneers are obtained thanks to peeling process. This cutting process induces lathe checks of the veneer with variable depth and spatial frequencies. In this work, we studied the influence of lathe checks on the mechanical properties of LVL thanks to a finite element model of LVL beams made of checked veneers. The checks were modelled as free spaces in the cross-section. Several typical check depths and frequencies were compared, with the beam tested edgewise or flatwise. The results show that the longitudinal modulus of elasticity and the shear modulus in flatwise bending are marginally affected by checking, while the shear modulus of the LVL beam is significantly reduced in edgewise bending if the check depth is important. This phenomenon is due to high shear deformations in the edgewise bending case, because checks are mainly horizontal in this state. Therefore, the check depth may also affect the resistance of LVL in edgewise bending, thus experimental testing of this assumption will be done.