Huaijun Wang

Date of Award

12-2000

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Forest Resources

Advisor

Stephen Shaler

Second Committee Member

James Fastook

Third Committee Member

Douglas Bousfield

Abstract

Wood particulate composites are inhomogeneous, short fiber materials. The behavior of such materials depends on the properties of the constituent elements (wood particles, fibers, and adhesives) and the manner in which they are organized (the microstructure). Research on the microstructure of these composites has been carried out for several decades. However, due to the complexity of the engineered structures, most existing works are either over-simplified or lacking in general representations. While experimental approaches to improve material performance are necessary, this thesis presents another approach for better depictions of such complex systems. In this research project, digital surrogates of the composite structures are created and tested in a virtual laboratory - the computer. Each structure is constructed by packing digital particulate elements. The electronic versions of wood fibers, strands or flakes are generated based on the known properties of their real-world counterparts, including stochastic descriptions of their geometries, and some physical and mechanical properties. More importantly, a certain level of intelligence built-in to the elements enables them to adjust their geometries on the basis of the interaction with other elements. As it is based on the very fundamental rules, this simulation methodology guarantees much more realistic descriptions of the microstructures compared with other models. This method allows controlled and repeatable experiments with virtually zero experimental and material costs. Since the structures of the virtual composites are digitized, it is fairly easy to obtain the information which may be impossible or hard to obtain from the real composites, such as the morphology of particle-to-particle bonds and the quantities of inter/intra-particle voids. It lays a more reliable foundation for further research on performance prediction and manufacturing optimization of the wood particulate composites.

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