Mixed-mode fracture analysis of adhesively-bonded joints using the ATDCB test specimen

To enable the widespread use of adhesive joints in industry applications, it is fundamental to be able to predict their strength. Cohesive zone models (CZM) require estimating mechanical and fracture properties of adhesives. Under mixed-mode, CZM require defining the most adequate propagation criterion of the adhesive to accurately predict the joints' behaviour. In this work, the Asymmetric Tapered Double-Cantilever Beam (ATDCB) mixed-mode test is studied to estimate the fracture envelope of three adhesives with different ductility. Pure-mode Tapered Double-Cantilever Beam (TDCB) and End-Notched Flexure (ENF) tests were also conducted. Numerically, mixed-mode CZM laws were built based on the obtained data, and the respective numerical results were compared with the experiments, which enabled validating the CZM laws and the mixed-mode propagation criterion of each adhesive. With this work, the mixed-mode CZM laws and the respective mixed-mode propagation criterion of three adhesives were proposed and validated for strength prediction of adhesive joints.