Numerical study of the influence of veneer lathe checks on the elastic mechanical properties of laminated veneer lumber (LVL) made of beech

Abstract

Laminated veneer lumber (LVL) is a well-known high-performance engineered wood product suitable for structural applications. However, the peeling process can induce lathe checks of the veneer with various depth and spatial frequencies. In this study, a finite element model (FEM) is proposed to describe and to analyze the influence of veneer lathe checks on the elastic properties of LVL. Firstly, the typical lathe check depths and frequencies were determined by means of different compression rates of the pressure bar when peeling. These experimental results served as input to the model to compare the influence of check depth and frequency on the elastic behavior of an LVL beam in four-point bending. The checks were modeled as free spaces in the cross-section that can be partially filled with glue. The results show that the longitudinal modulus of elasticity is marginally affected by checking, while the shear rigidity of the LVL beam is significantly reduced in edgewise bending if checks are not glued. Gluing checks, even under consideration of a low Young’s modulus of glue, highly reduces the effect of checking on the elastic mechanical properties of LVL.