Computational Modeling of Strand-Based Wood Composites

Abstract

A nonlinear stochastic model has been formulated to simulate the stress-strain behavior of strandbased wood composites based on the constitutive properties of the wood strands. Prediction models of this type save time and money in the development of wood composites by computationally gauging the effects of varying raw material characteristics with limited fabrication and testing of the full-scale product. The proposed model uses a stochastic-based materially nonlinear finite-element code with extended capacity to perform Monte Carlo simulations to predict the stress-strain behavior of [Ϯ15] s and [Ϯ30] s angle-ply laminates in tension and compression. The nonlinear constitutive behavior of the wood strands is characterized within the framework of rateindependent theory of orthotropic plasticity, where the plastic flow rule is in accordance with the Tsai-Wu criterion. Shear strength and stiffness of the strands, as well as the interaction parameter of the Tsai-Wu criterion have been estimated through a minimization technique developed in the present study. The model's accuracy was validated through comparisons of the numerical simulation results and experimental data. Excellent agreement was found.

Variability of the Compressive Strength of Parallel Strand Lumber

“…The computational model builds upon previous efforts by one of the writers ͑Clouston and Lam 2001Lam , 2002Clouston 2006͒ to develop finite-element models of SCL mesostructures that capture the variation in properties between strands and incorporate a reasonable model for the failure surface of the strands. Although stochastic models have been proposed for the mechanics of the PSL cross section ͑Bejo and Lang 2004͒, this is the first attempt to model the lengthwise features of the mesostructure.…”

A Probabilistic Approach to the Simulation of Non-Linear Stress-Strain Relationships for Oriented Strandboard Subject to In-Plane Tension

“…Clouston and Lam [8] incorporated the probability based techniques developed by Wang and Lam into 2-D non-linear stochastic finite element model to predict the mechanical response of angle-ply wood strand laminates subjected to multiaxial stress conditions. This was one of the first attempts to model wood-strand composites with varying ply orientations and to model non-linear compression behaviour.…”

“…Excellent agreement was observed between the predicted and experimental probability distributions of ultimate strength and MOE in tension, compression and bending. Further studies by Clouston and Lam [9,10] developed the model into a 3-D non-linear stochastic finite element model for predicting the probabilistic distribution of strength, stiffness and failure load of angle-ply laminates subjected to tension, compression and bending. Clouston [11] and Arwade et al [12] further developed this model to enable it to predict the strength and MOE of large section parallel strand lumber (PSL) members loaded in tension, compression and bending.…”

Modern structural wood products

“…Currently, parallel strand lumber products are manufactured in facilities in both Canada and the United States [9,10]. Relatively few journal publications are available on the product; however, computer modelling of this type of strand-based products has been studied [11][12][13]. In Canada, Douglas fir veneers and in the United States Southern pine veneers are primarily utilized in the production of parallel strand lumber.…”