An Optimisation Methodology for Ship Structural Design using CAD/FEM Integration

In ship structural design, scantling optimisation using mathematical algorithms is not yet largely implemented in industry. Optimisation with mathematical algorithms can be very helpful to find the best solution (minimum weight, minimum cost, maximum inertia,etc.). Typically, finite element analysis (FEA) tools are used in ship structural assessment. But, to build a FEM model from a CAD one is not easy. It needs a big amount of manual work. In the present work, an innovative optimisation workflow was developed. The following steps are carried automatically without any manual intervention. First, from the 3D CAD model, an idealized CAD model is created by the idealization module to take into account the FEM needs. Then, the idealized CAD model is transferred to the FEM tool. After that, the FEM model is meshed and loaded. After FEM solving, the results (stress, displacement, volume etc.) are transferred to the optimiser. The optimiser evaluates the values of the objective function and the constraints previously defined and modify the design variables (plate thickness and the stiffener scantling) to create a new structural model. After several iterations, the optimum solution is evaluated.