Statistical Analysis of Flaw Strength Spectra of High-Modulus Fibers

A new multistage tension testing procedure is developed that enables the statistical estimation of the flaw strength spectra of high-modulus fibers. The mathematical development of the procedure assumes the compound Poisson process model in distance to represent the probabilistic aspects of flaw occurrence along the fiber. The multistage procedure is applied to commercially available boron filaments, and the results are compared with those obtained on the same filaments using the conventional single-stage tension testing procedure with the Weibull distribution as the underlying model. The experimental results illustrate the dangers of fiber strength data extrapolation.