Numerical simulations of delamination in fibre reinforced plastic shell structures using XFEM

The simulation of delamination type failure in multi-layered fibre reinforced plastic shells with the standard finite element method is numerically expensive. In the standard simulations, the cohesive zone model that combines the damage and fracture mechanics is inserted at all available interfaces and each ply should be simulated independently. In this thesis the eXtended Finite Element Method (XFEM), the mixed-mode cohesive zone model, the contact formulations, and the damage criterion are incorporated into a new algorithm to study the delamination. A shell formulation is developed in the geometrically non-linear regime to study the response of shells. This formulation is enhanced through the XFEM topology to be able to model discontinuous domains and a mixed-mode cohesive formulation is applied to track the delamination growth. In this thesis, the simulation can be initialized in an intact laminate. Thus, unlike formulations in existing finite element models, there is no necessity of incorporating the cohesive zone model at all available interfaces. The possibility to track the delamination growth is locally provided and the delamination front is formed without remeshing process.