Direct comparison between monofilament and multifilament tow testing for evaluating the tensile strength distribution of SiC fibers

• Multifilament test results almost correspond to monofilament test results. • Fiber diameter variation does not affect multifilament test results considerably. • Diameter variation along gauge length may affect multifilament test result. The tensile strength distributions of five types of silicon carbide (SiC) fiber, namely, Nicalon, Hi-Nicalon, Hi-Nicalon TypeS, Tyranno ZMI and Tyranno SA, were evaluated by monofilament and multifilament tow tensile testing with the estimated Weibull parameters being compared from each method. Whereas values for the Weibull scale parameter were found to be similar for both the monofilament and multifilament test methods, the Weibull shape parameter obtained from multifilament tow testing tended to be greater than that obtained from monofilament testing. The effect of diameter variation within individual fibers on the multifilament tow test results was investigated by Monte-Carlo simulations. In contrast with the experimentally obtained results, the shape parameters calculated by Monte-Carlo simulation exhibited good agreement with the monofilament test results.