Determination of Carbon Fiber Strength Distribution Using Bundle Fiber Tensile Test: Correction of Measurement System Elongation and Kinetic Friction Between Fibers in the Fiber Bundle

In this study, we investigated the improvement in carbon fiber (CF) bundle tensile tests. To effectively evaluate the mechanical properties of CF using the fiber bundle tensile test, measurement of system elongation correction considering nonlinear behavior and Weibull analysis using fitting of stress–strain curves was conducted. Shear-lag theory analysis revealed that the elongation in the nonlinear measurement system was largely governed by the adhesive layer deformation within the tabs. A nonlinear measurement elongation correction method was proposed that can be applied to specimens of different widths. Weibull parameters were extracted by fitting the stress–strain curves, while considering the effect of the kinetic frictional force. The obtained parameters from the fiber bundle tensile test corresponded to those obtained from the SFTT. Thus, the proposed fiber bundle test can be a simple method for evaluating fiber strength distribution. Graphic Abstract