REFINED BEAM FINITE ELEMENT TO ANALYSE HULL STRUCTURES

Accurate and reliable analysis of hull structures requires the employment of complex 3D Finite Element (FE) models which are, generally, computationally expensive. For this reason, simple beam models have extensively been utilized in the literature to model the mechanical behavior of ship hulls. However, due to their simplicity, these 1D models entail various assumptions and do not provide accurate and reliable results for hulls with complex structural details, such as cut-outs or reinforcements. In the present study, refined 1D FE models for the analysis of marine vessels have been developed by using the well-known Carrera Unified Formulation (CUF). According to CUF, refined kinematics beam models that go beyond classical theories (e.g. Euler and Timoshenko theories) can be easily developed by expressing the displacement field as an expansion in terms of generic functions, whose form and order are arbitrary. Hence, the stiffness and mass matrices are written in terms of fundamental nuclei, which are independent of the adopted class of beam theory and the FE approximation along the beam axis. As a particular class of CUF models, Lagrange polynomials have been used in the present work to formulate beam models at the component scale. According to this approach, each structural component (e.g. hull, longerons, bulkheads, and floors) can be modeled by means of the same 1D formulation. Various marine structures of varying complexity have been analysed. The results clearly demonstrate the enhanced capabilities of the proposed formulation, which is able to replicate solid/shell ANSYS solutions of both simple and relatively complex marine constructions with very low computational efforts.