XFEM investigation of adhesive bonding on crack surfaces in PMMA under mixed-mode loading

The current study used the Extended Finite Element Method (XFEM) combined with cohesive zone Modeling for the adhesive to simulate Mixed-Mode I–II fracture in rectangular polymethyl methacrylate (PMMA) specimens containing a 30 mm edge crack, and also a crack length and specimen width ratio of 0.5. Tensile tests were performed on standard dog-bone samples to determine the material properties of PMMA used in the simulations. Two groups of specimens were Modeled: one with simple (unbonded) cracks and another with cracks whose faces were adhesively bonded. XFEM simulations were used to evaluate fracture strength and crack propagation paths, and the results were compared with the available experimental data. The XFEM predicts fracture strengths for different loading Modes within approximately 6% error compared to the experiments and accurately reproduces crack propagation paths under Mode I, Mode II, and Mixed-Mode conditions. Bonded specimens show higher fracture strength than unbonded specimens, and the simulations capture the brittle fracture behavior observed at peak load in the force-displacement responses. These findings demonstrate that XFEM combined with cohesive zone Modeling is an effective tool for analyzing adhesive-bonding effects on Mixed-Mode fracture in PMMA.