Moisture effects on Mode II delamination behavior of carbon/epoxy composites
Abstract:Moisture effects on Mode II interlaminar fracture in T300/914C and T300/M10 carbon/ epoxy composites were investigated by using ENF specimens exposed to different hygrothermal conditions. Crack growth behavior, interlaminar shear strength, glass transition temperature and fractographs of the materials were examined toward establishing the possible mechanisms of moisture effects. It was found that Mode II fracture toughness of T300/M10 is more sensitive to moisture than that of T300/914C. For T300/914C, the matrix was plasticized by water and thus GIIc increased slightly. With further moisture absorption, swelling action weakened the interface and led to reduction of fracture toughness. For T300/M10, moisture primarily weakened the interfacial strength and resulted in decrease in GIIc. It seemed that water plasticization contributed to the enhancement of delamination toughness of the fiber-matrix system with strong interface, and degraded the toughness of the system with weak interface due to a decrease of the fracture area. However, for both of the two systems, the swelling action, which weakened the interface bond, always reduced the delamination resistance.
Document Type: Research Article
Affiliations: 1: Department of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, 100083 Beijing, China 2: DLR Institute of Structural Mechanics, 38108 Braunschweig, Germany
Publication date: January 1, 1996