Prediction of the load-bearing capacity of an adhesive-bonded joint is of practical importance for engineers.
This paper introduces interface fracture mechanics approach to predict the load-bearing capacity of
composite/metal bonded joints. The adhesion strength of composite/steel bonding is evaluated in terms of the
energy release rate of an interfacial crack and the fracture toughness of the interface. Virtual crack closure
technique (VCCT) is used to calculate energy release rates, and bi-material end-notched flexure (ENF)
specimens are devised to measure the interfacial fracture toughness. Bi-material ENF specimens gave consistent
mode II fracture toughness (GIIc) values of the composite/steel interface regardless of the thickness of
specimens. The critical energy release rates of double-lap joints showed a good agreement with the measured
fracture toughness. Therefore, the energy-based interfacial fracture characterization can be a practical engineering
tool for predicting the load-bearing capacity of bonded joints.