Nonlinear Behavior of IM7 Carbon Fibers in Compression Leads to Bending Nonlinearity of High-Strain Composites

This paper presents an experimental characterization of carbon fibers under compression and the influence of their nonlinear behavior on the bending nonlinearity of high-strain composites (HSC). The study is focused on HexTow IM7, a pan-based carbon fiber compressed under in-situ scanning electron microscopic (SEM) imaging. The sample preparation and experimental procedure of both single fiber direct compression tests and column bending tests of HSC samples are presented. Nonlinearity at the individual fiber level could not be observed due to the limitations of the load cell in the single fiber direct compression experiment. Using the column bending tests, a shift in the neutral axis due to the nonlinear compression behavior of fibers is observed.