Measurements of fiber orientation and elastic-modulus analysis in short-fiber-reinforced composites

This paper presents an image analysis method for measuring fiber orientations in short-fiber-reinforced composites and a mathematical procedure for predicting the elastic modulus of the composites according to the measured fiber-orientation distribution (FOD). The method determines the FOD from the ratio of fiber matrix perimeter length between two orthogonal planar cross-sections of polished composite samples. The analysis algorithm of the method is much simpler than previously reported methods and is efficiently applied to composites with axially symmetric FOD. To verify the theory, FOD measurement and tensile testing were performed on Al2O3/Al composites fabricated by squeeze casting. The elastic modulus values determined by the tests were compared with the theoretical value, and the agreement was satisfactory.