Implementation and validation of the Ladeveze damage model for numerical simulations of composite materials

This Master Thesis focuses on the implementation and validation of a numerical damage model for composite laminates, within the Abaqus finite element environment. The aim is to develop a generalised and reliable strategy for simulating the mechanical response of fibre-reinforced laminates under various loading conditions. The core of the work consists in the implementation of the Ladevèze continuum damage model (LV) via a user-defined UMAT subroutine in Abaqus. The theoretical formulation of the LV model has already been extensively validated in previous studies; the purpose of this work is therefore to verify the correctness and robustness of its implementation within the finite element framework. This model incorporates stiffness degradation, matrix plasticity, and irreversible damage evolution mechanisms at the ply level. Model calibration is performed based on experimental characterisation tests, allowing for accurate reproduction of the material's nonlinear behaviour. The resulting framework enables the virtual investigation of damage initiation and progression in laminated composite structures. Comprehensive validation of the implementation has been carried out against a range of static experimental tests, including tensile, compressive, cyclic shear, Double Cantilever Beam (DCB), End Notched Flexure (ENF), Compact Tension (CT), and Compact Compression (CC) tests. The comparison demonstrated good agreement between experimental and numerical results, confirming the capability of the implementation to reproduce both fibre and matrix dominated damage mechanisms. Furthermore, cohesive damage models were also implemented to capture interlaminar fracture, thus enhancing the predictive capability for delamination phenomena.