The Application of 3-D X-Ray Tomography with Finite Element Analysis for Engineering Properties of Strand-Based Composites

Strand-based composites are formed by arranging wood strands in a mat and bonding them together with adhesives under heat and pressure. The performance of these products is governed by the properties of wood strands, adhesive, manufacturing strategy, and production process. In this paper, a method of building a model to represent internal structure of oriented strandboard (OSB) based on x-ray tomography analysis and to calculate anisotropic engineering constants of OSB using finite element (FE) technique is presented. OSB samples from mixed hardwood species were scanned with an x-ray tomography machine and internal structure of the composite was reconstructed into three dimensional images. Internal variations of material density were calculated during image processing, and the voids were identified and reconstructed. The in-plane and out-of-plane distribution of density and voids variations were demonstrated. It was found that the x-ray tomography and image processing technology can be successfully used to obtain density distribution and voids structure in OSB. A three layer (two face layers and one core layer with different flake alignment levels) finite element model was created to investigate performance of anisotropic wood composite (i.e., OSB). The FE geometry model was based on X-ray tomography images reflecting the actual microstructure of the testing samples. The predicted in-plane moduli showed reasonable agreement with measured data. The study showed that OSB performance can be characterized numerically with FE simulation to achieve the goal of digital testing of the composite material.