2|3D Finite Elements for the Non-Linear Analysis of Composite Structures Manufactured via AFP

This work presents a novel class of 2|3D finite elements developed within the Carrera Unified Formulation (CUF) for the analysis of composite structures manufactured via Automated Fiber Placement (AFP). Unlike classical CUF-based two-dimensional elements, the proposed formulation introduces a full three-dimensional Jacobian in the kinematic description. This feature enables the accurate modeling of variable-thickness structures, which are typical of AFP processes and include defects such as overlaps, gaps, and local thickness variations. The use of a 3D Jacobian allows capturing these geometric irregularities without the need for fully three-dimensional discretizations, thus maintaining computational efficiency while improving accuracy. The formulation is applicable to both plates and shells, including components with complex geometries and integrated reinforcements. The proposed elements are extended to nonlinear analysis, accounting for geometric nonlinearities. This enables the study of stability phenomena such as buckling and post-buckling in the presence of manufacturing defects. Numerical results highlight the strong influence of thickness variations on the structural response of thin composite shells. Finally, the approach is demonstrated on composite components with complex geometries, showing its capability to provide accurate and efficient predictions. The proposed 2|3D elements represent an effective tool for bridging the gap between classical 2D formulations and full 3D models in the analysis of advanced composite structures.