An eccentric shear-lag model and implications on the strength of fibrous composites

Abstract

The stress field in the vicinity of a broken fiber-reinforced composite is analysed by means of a shear-lag model. The broken filament is positioned eccentrically relative to its neighboring fibers to simulate the commonplace non-uniformity ot fiber spacing within the transverse plane, it is shown that a fiber break gives rise to severe bending, in addition to tension, in the neighboring fibers—with a substantial overstress focused on the nearest unbroken filament. The complex nature of the stress field, which is caused by the failure of a fiber within a composite casts doubt on the applicability of failure statistics derived from tensile failure data of single fibers, which is commonly used to predict the strength of composites.