Journal of Materials Science, Vol.48, No.10, 3623-3637, 2013
Effects of fiber gripping methods on the single fiber tensile test: I. Non-parametric statistical analysis
Single fiber tensile tests using two different gripping methods were carried out on various fiber lengths. One method (the glue-tab grip method) consists of mounting a fiber onto a rigid tab as specified in ASTM C1557-03 using an adhesive, while the other (the direct grip method) involves directly clamping a fiber using poly(methyl methacrylate) blocks. The tensile moduli obtained by the glue-tab grip as a function of the fiber gauge length are clearly different from those of the direct grip for fiber length between 2 and 10 mm, based on graphical statistical analyses using kernel density and q-q plots. This difference is caused by the gripping effect. In addition, the tensile strains and strengths obtained by the glue-tab grip were different from those of the direct grip at the short fiber gauge lengths (i.e., 2-10 mm). The differences between the tensile properties (i.e., modulus, strain, and strength) for the two grips measured with the 60-mm fiber length were not statistically significant compared to the results with the short fiber lengths.