Interfacial fracture toughness test methodology for adhesive bonded joints

A compact mixed mode (CMM) specimen was employed to determine the interfacial fracture toughness of adhesively bonded joints. Finite element analysis modeling for an interface crack in the CMM specimen provided the necessary stress intensity factor calibration solution. An interface crack mixed mode fracture toughness test methodology has been developed. Fracture toughness tests for interface cracks in adhesive joints were subjected to different global mixed mode loading conditions. The results showed that the mode II fracture toughness generally displayed a larger value than the mode I toughness. Failure criterion based on a failure analysis diagram or an effective stress intensity factor were proposed for interface cracks loaded under different mixed-mode fracture conditions.