Milad Jabbari - Postdoctoral Research Fellow, University of Isfahan, Isfahan;
Gary M. Raftery - Senior Lecturer, University of Auckland, Auckland, New Zealand
James B.P Lim - Professor, University of Waikato, Hamilton, New Zealand

Exposure to environmental stresses can weaken theconnection of epoxy-bonded CFRP-strengthened steelelements. As a result, designers often express concernabout possible premature delamination arising fromcombined peel and shear effects at the CFRP-steelinterface. This study was undertaken to further knowledgein relation to the peel failure of epoxy-bonded CFRP-tosteeljoints subjected to hygrothermal conditioning. Twocommercially available structural epoxy adhesives wereexamined. Hygrothermal conditioning may cause theadhesion failure near to the edges of the adhesive joints.The load-carrying capacity and strain energy release rateof adhesive joints depend on the adhesive andhygrothermal environment, and can be degraded up to۱۵%. Humid and wet conditioning cause up to ۴۴% and۶۳% drop in elastic modulus, ۳۱% and ۵۵% reduction intensile strength, and ۳۲% and ۴۴% increase in averagemaximum strain of adhesive materials, respectively. Anonlinear finite element analysis which employed acohesive zone model was conducted and showed that theproposed modified experimental arrangement wasdominated by mode I behaviour.

Adhesively-bonded CFRP-to-steel joints,Mode I fracture, Humid and wet conditioning,Environmental durability.