Failure of fiber bundles

The paper investigates the discrepancy between experimental data and theory on the tensile behavior and strength of fiber tows. Experimental data were compared to predictions from single fiber properties. A numerical model allowed the scatter in tow strength data to be generated, and the influence of the following factors to be examined: uncertainty in fiber statistical parameters estimation, and in the number of fibers within tows, non-uniform loading and equal or imperfect local load sharing conditions when a fiber fails. This approach was applied to SiC (Nicalon NLM 202 and Hi-Nicalon) fiber tows containing 500 filaments. It was shown that local load sharing was a preponderant factor that influenced tow strength data and the associated scatter. Implications in composite failure are finally discussed.