The aligned ellipsoidal inclusion composite is of particular interest as the shape of the inclusion can be manipulated to conform to various reinforcing geometry, such as long fiber, short fiber, particulate, flake, lamina, continuous ribbon and discontinuous ribbon. This paper demonstrates how the Young’s Modulus of such an orthotropic material can be approximated based upon combinations of the age-old mechanics-of-materials approach. By writing the Young’s Modulus in all three principal orthogonal directions in a nondimensionalized form, the indices of the inclusion volume fraction reveals the existence of a reinforcement parameter, which ranges from zero (for minimum reinforcing shape) to unity (for maximum reinforcing shape). The reinforcement parameters are independent from material behavior of the individual phases and the inclusion concentration. Semiempirical relationships between reinforcement parameters in these three orthogonal directions and the inclusion shape are obtained by curve-fitting at special conditions. This simplified method is conveniently executable and hence suitable for design of composite products that consist of ellipsoidal, or nearly ellipsoidal inclusions.
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