Predictive Models for Elastic Bending Behavior of a Wood Composite Sandwich Panel

TLDR

Wood‑strand composite sandwich panels made from lodgepole and ponderosa pine strands are proposed as building envelope replacements, and predicting their bending behavior under typical loads is essential. The study aims to develop theoretical and finite element models to evaluate the elastic bending behavior of a wood‑strand composite sandwich panel with a biaxial corrugated core. Material properties were obtained from tensile tests and used in Euler–Bernoulli, Timoshenko, and FE models, followed by a sensitivity analysis of bending stiffness to material variation. Shear deformation was found negligible, and the Euler–Bernoulli, Timoshenko, and FE models predicted bending stiffness within 3.6%, 5.2%, and 6.5% of experimental values, respectively.

Abstract

Strands produced from small-diameter timbers of lodgepole and ponderosa pine were used to fabricate a composite sandwich structure as a replacement for traditional building envelope materials, such as roofing. It is beneficial to develop models that are verified to predict the behavior of these sandwich structures under typical service loads. When used for building envelopes, these structural panels are subjected to bending due to wind, snow, live, and dead loads during their service life. The objective of this study was to develop a theoretical and a finite element (FE) model to evaluate the elastic bending behavior of the wood-strand composite sandwich panel with a biaxial corrugated core. The effect of shear deformation was shown to be negligible by applying two theoretical models, the Euler–Bernoulli and Timoshenko beam theories. Tensile tests were conducted to obtain the material properties as inputs into the models. Predicted bending stiffness of the sandwich panels using Euler-Bernoulli, Timoshenko, and FE models differed from the experimental results by 3.6%, 5.2%, and 6.5%, respectively. Using FE and theoretical models, a sensitivity analysis was conducted to explore the effect of change in bending stiffness due to intrinsic variation in material properties of the wood composite material.