Extraction of Weibull parameters of fiber strength from means and standarddeviations of failure loads and fiber diameters

The errors in using an average fiber diameter to calculate the mean strengt h (sigma (m)), Weibull reference strength (sigma (0)), and Weibull modulus (m) from failure loads of fibers were examined experimental. Although the u se of an average diameter gave very good estimates of sigma (m), the error in the Weibull parameters (sigma (0) and m) was significant, which supporte d the recent simulation results. Computational approaches to reduce these e rrors have been considered, and a numerical procedure to extract the Weibul l parameters from the means and standard deviations of the load and fiber d iameter has been proven feasible, provided the sample population is large. parametric studies hare shown that sample populations of similar to 175 are required to obtain results within an error of 10%. The recommended sample populations for commercial fibers are 75-200, depending on the scatter in t he fiber diameter and the acceptable error.