Cohesive Zone Modelling using Finite Element Method : Master’s thesis in mechanical engineering

Sammanfattning

This work presents the development and evaluation of a practical and reliable method for extracting CZM material parameters and simulating adhesive joints using CZM within the framework of FEM. The objective was to accurately simulate adhesive joint failure under Mode I (Peel), Mode II (shear) and mixed mode loading conditions by combining experimental testing with numerical modelling. Mechanical tests were performed using DCB and ENF specimens. Fracture energy was extracted usingthe J-integral method, and cohesive parameters were derived by constructing stress–separation curves. These parameters were then implemented into FEM simulations using multiple solver configurations in ANSYS, including both implicit and explicit solvers with interface- and contact-based CZM formulations. The simulation results showed strong agreement with experimental data. The DCB simulationspredicted peak loads with a max error of 5–10% of the experimental values, while the ENF simulationssuccessfully captured the correct trends and stiffness. Despite some limitations due to availableequipment and modelling assumptions, the method proved to be effective for evaluating adhesive behaviour. After the simulations proved to correlate with mechanical testing, a mixed-mode validation case wasperformed to demonstrate the correlation between the CZM parameters and their implementation in ANSYS. This approach has potential applications in engineering contexts where reliable virtual testingof adhesive joints is desirable, such as in defence, and could also be implemented in other mechanicalstructural design problems.