Paper number 1286

INFLUENCE OF ELECTRON RADIATION AND WATER ABSORPTION ON IMPACT AND CAI FRACTURE BEHAVIOR OF CARBON/EPOXY COMPOSITE

Kenjiro Komai, Kohji Minoshima, Kazuto Tanaka and Kohji Nakaike

Department of Mechanical Engineering, Graduate School of Engineering,
Kyoto University
Yoshida-Honmachi, Sakyo, Kyoto 606-8501, Japan
E-mail: kazuto@linde.mech.kyoto-u.ac.jp

Summary

The influence of water absorption and electron radiation on impact fracture and compression after impact (CAI) behavior was investigated using carbon fiber reinforced epoxy matrix composite (MM-1/982X), having a quasi-isotropic stacking sequence of [0°/±45°/90°]2S. Some specimens were immersed in deionized water at 80°C for about two months, which will be referred to as wet specimens. Both wet and dry (conditioned in air: RH 30%) specimens were irradiated in air with electron energy of 1.5MeV, resulting in a total absorbed dose of 10 MGy (1(103Mrad). The impact tests were carried out by a falling weight tester. Impact induced internal damage was observed with a scanning acoustic microscope (SAM). The delamination area was slightly increased by electron radiation and sharply increased by water absorption. The CAI strength was decreased in the order, dry specimens, irradiated specimens, irradiated after water absorbed specimens, wet specimens. The fracture surface was closely examined using a scanning electron microscope, and the fracture mechanisms were discussed.

Keywords

water absorption, electron radiation, impact, compression after impact, delamination, fiber/matrix interface, scanning acoustic microscope, CF/epoxy.