A new mixed mode test for carbon/epoxy composite systems

• Published in: Composites. Part A, Applied science and manufacturing Applied science and manufacturing, 2003-01, Vol.34 (11), p.1125-1131
• Main Authors: Tracy, Gregory D., Feraboli, Paolo, Kedward, Keith T.
• Format: Article
• Language: English
• Subjects: Applied sciences; B. Fracture toughness; Exact sciences and technology; Forms of application and semi-finished materials; Laminates; Mixed mode delamination; Polymer industry, paints, wood; Technology of polymers
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/S1359-835X(03)00205-7

The present research examines analytically and experimentally the mixed mode interlaminar fracture toughness of a resin film infused (RFI) carbon fiber/epoxy laminate, namely a IM7-AS4/3501-6 hybrid composite system. The inability to develop representative interlaminar failure in composites with current mixed mode test configurations motivated this particular investigation. The paper is part of a more extensive research effort concerned with the effects of stitching upon the mixed mode fracture toughness of a RFI composite. A new mixed mode test configuration is suggested, the Single Leg Four Point Bend (SLFPB), which provides a robust method with small specimens and a simple apparatus. Closed form fracture mechanics-based strain energy release (SERR) calculations have been established for this configuration. Finite element analysis was conducted to validate the closed form solution. Results show a very good agreement between analytical solutions, numerical simulation and the newly designed SLFPB experimental test.