Paper number 370

DIRECT EVALUATION OF AXIAL COMPRESSIVE PROPERTIES OF CARBON FILAMENT

Kazuhiro Fujita, Hiroshi Shioyama, and Yoshihiro Sawada

Osaka National Research Institute, AIST,
1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577 Japan

Summary

In order to utilize the fibers' high performance, axial compressive properties of carbon fibers were measured. Direct compressive test of single filament and in situ observation were applied to obtain more reliable data than indirect methods. For such test, new apparatus was composed that could be operated under optical microscope. Pitch- and PAN-based fibers with almost the same modulus were tested. Pitch-based fiber broke with shear mode when gauge length-diameter ratio was less than 10. However, almost all the tests of PAN-based fibers showed buckling mode even with the same gauge length-diameter ratio. They were very similar to failure appearances of the recoil test. Obtained compressive strength was 0.62 GPa for pitch-based fiber and 0.93 GPa for PAN-based fiber. Both were different from what was expected from single filament three point bending test results.

Keywords

axial compressive test, single filament, in situ observation, failure mode, compressive strength.