Research will be conducted to investigate mixed mode fracture mechanisms of a unidirectional carbon/epoxy composite material using the modified Iosipescu test technique. Intralaminar fracture mechanisms in the composite will be analyzed numerically and experimentally. The research will use finite element methods extensively to study the mixed mode stress intensity factors and the energy release rates associated with intralaminar cracks in the composite Iosipescu specimens tested under biaxial stress conditions. In addition, adhesively bonded composite systems will be tested under mixed mode loading conditions using the newly designed Iosipescu fixture. Linear and non-linear finite element calculations of the adhesive joints in the Iosipescu specimens will be performed. The fundamental significance of this research is that it will contribute to the understanding of intralaminar fracture mechanisms in carbon fibre/epoxy composites caused by biaxial stress conditions. Moreover, the study will provide new insights into the complex failure phenomena of advanced adhesive joint systems. The practical significance is that after comprehensive numerical and experimental investigations of the newly designed biaxial test technique, the test will have great potential to become standard for mixed mode failure and fracture analysis of many advanced composite systems.
