The applicability of J-integral approach in the determination of mixed-mode fracture energy in a ductile adhesive

In this work, a J-integral-based data reduction approach was used for fracture characterisation of a ductile two component epoxy adhesive with steel adherends under mixed-mode loading. The applied method is a closed form relation which requires only rotation angle of the load introduction points and the applied load as input. Double Cantilever Beam (DCB) tests as well as Mixed Mode Bending (MMB) tests (with different mixed-mode ratios) were carried out to achieve a wide range of mode-mixity. Based on the measured values of fracture toughness Go the full fracture envelope of the adhesive was developed by using the Benzeggagh-Kenane (B-K) fracture criterion. Good agreement between the FE and experimental load-displacement curves proved that the applied method is accurately capable of determining the fracture toughness of the adhesive. The proposed approach shows high potential to account the dissipated energy in the fracture process zone in the ductile adhesives.