EFFECTS OF MICROSTRUCTURAL HETEROGENEITY IN CEMENT EXCELSIOR BOARD

Heterogeneity in the properties and arrangement of constituents can ha ve an important effect on a composite's properties. This paper evaluat es the effects of variability in wood strand dimensions, mechanical pr operties, and orientation on the engineering properties of cement exce lsior board. The finite element method is used to analyze a heterogene ous three-dimensional microstructure of strands, predicting elastic an d strength properties. Results suggest that variability in strand mech anical properties can significantly lower composite tensile and compre ssive strengths, while composite stiffness is not affected. The model also predicts that relatively modest alignment of strands can lead to significant increases in composite strength and stiffness in the direc tion of alignment.