The Influence of Voids on the Engineering Constants of Oriented Strandboard: A Finite Element Model
Keywords:Finite element modeling, strand alignment level, in-plane elasticity, laminate model, linear expansion coefficient, structural strandboard, voids
AbstractA laminated model based on continuum theory combined with finite-element analysis (FEA) was used to predict the influence of voids on engineering constants of oriented strandboard (OSB). Cylindrical voids with three material density classes in the void region were considered at various void volume fractions (VVFs) and matrix anisotropies. It was found that the presence of voids resulted in substantial decreases in the elastic moduli and Poisson ratio of OSB. The hygroexpansion coefficients were affected little by voids. The elastic constants normalized with their void-free (matrix) values were found to depend little on the anisotropy of the matrix, especially at high VVFs. Increases of material density in the void region led to increases in predicted elastic constants. The predicted moduli values for the void models with certain material densities correlated well with available experimental data for the selected panel structures. The FEA provided a comprehensive numerical tool in predicting localized elastic properties of porous OSB. The model is the basis for modeling three-layer boards and for constructing in-plane modulus map of full-size panels.
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