Abstract: In this paper the cumulative distribution function (c.d.f) of tensile strength of the impregnated fiber bundles is investigated systematically by mathematical statistics. It is shown that the tensile strength c.d.f. of the impregnated bundles is affected by the kinds of the fibers and the properties of the matrices. Both Guass c.d.f. and Weibull c.d.f. can be accepted to be used as the description for the experimental strength c.d.f. of the impregnated bundles at 95% confidence level. But it is found that the tensile strength c.d.f. of the bundles varies from Gauss c.d.f. to Weibull c.d.f. with the increase of the failure elongation of the matrices.

Key words: composites, mechanical properties, tensile strength, strength statistics