Micromechanical approach to the tensile strength of unidirectional composites

This paper deals with the strength of dry bundles and unidirectional composites. Tensile tests of dry bundles and unidirectional composites of carbon fibers and alumina fibers are carried out. The strength of a dry bundle is compared with Coleman's theory and it is shown that the strength of a dry bundle can be well predicted by Coleman's theory. As for a unidirectional composite, test data are compared with the Rosen model, the Zweben model, and the modified Zweben model. It has been confirmed that the Rosen model overestimates the strength whereas the Zweben model underestimates it. A modified Zweben model can represent the actual failure pattern, although some subjects are left for future investigation.