Numerical Comparison of Cohesive Zone and Extended Finite Element Methods for Mode I Fracture of Adhesively Bonded Joints

Adhesively bonded joints are increasingly used in modern lightweight structures, where accurate prediction of fracture behaviour is essential for ensuring structural reliability. This study numerically investigates the Mode I fracture of a Double Cantilever Beam (DCB) specimen using two computational approaches-the Cohesive Zone Model (CZM) and the extended Finite Element Method (XFEM)-and compares their predictions with the reference Virtual Crack Closure Technique (VCCT) results reported by Jokinen et al. (۲۰۱۵). All simulations were performed in the elastic regime using identical material properties and boundary conditions to ensure a consistent basis for comparison. The CZM was implemented through both surface-based and element-based cohesive formulations governed by a bilinear traction-separation law, while XFEM employed the maximum principal stress criterion for crack initiation and a fracture-energy-based evolution law. The results show excellent agreement between both numerical models and the benchmark VCCT response, with peak loads within ۵-۱۰% of the reference value. Surface- and element-based CZM produced nearly identical results, though the surface-based variant offered smoother convergence. XFEM achieved comparable accuracy with reduced mesh sensitivity and no need for a predefined crack path, but displayed minor post-peak oscillations due to element-wise damage evolution. Overall, the study confirms that both CZM and XFEM can accurately reproduce the elastic fracture behaviour of adhesively bonded joints. The surface-based CZM provides the most efficient and numerically stable formulation for Mode I fracture, while XFEM offers superior flexibility for problems involving unknown or evolving crack paths.

کلیدواژه ها:

Adhesively bonded joints ، Double Cantilever Beam (DCB) ، Mode I fracture ، Cohesive Zone Model (CZM) ، extended Finite Element Method (XFEM) ، traction-separation law ، damage mechanics ، fracture energy ، numerical simulation