Simulation of interlaminar damage in mixed-mode bending tests using large deformation self-adaptive cohesive zones

Cohesive zone models are common tools for the simulation of delamination since two decades. However, application of these models in a quasi-static finite element framework requires a sufficiently fine discretization to resolve a quasi-brittle process zone. As an alternative to mesh refinement, an adaptive approximation of the growing delamination was obtained in earlier work by enriching the elements in the fracture process zone. Discretization-induced numerical instabilities are thereby avoided and a standard Newton–Raphson iterative scheme remains applicable. This enriched 2D cohesive zone model is here extended to a large deformation self-adaptive finite element framework, which makes it suitable for general engineering applications where geometrical and material non-linearities are expected. Based on recent experimental results from miniaturized mixed-mode bending tests, an irreversible mixed-mode traction–separation law is considered for the simulation of delamination over a wide range of mode mixities. The developed model is used for the simulation of mixed-mode bending tests on bi-material interfaces and the response is compared to the experimental results. Numerical simulations using coarse discretizations in a quasi-static finite element framework show the effectiveness of the self-adaptive cohesive zone model.