Automatic Parametric Hull Form Optimization of Fast Naval Vessels

The present work shows the outcomes of a research project among the Department of Naval Architecture and Marine Engineering of the University of Genoa and Cetena S.p.A. for the Italian MOD in the frame of National Defence Research Plan. An automatic optimization study of the fore hull forms of a fast frigate is presented; it has been performed with a proper integration of a commercial optimization system, a parametric geometric modelling software and two different ship hydrodynamic analysis tools to predict the steady (wave resistance) and unsteady (seakeeping) performance of each design candidate. The fully automatic optimization algorithm, used to evaluate several thousands of design alternatives, takes into account a constrain set composed both by geometrical tolerances and minimum stability characteristics of the hull defined in a preliminary design study mentioned and briefly recalled in the paper. The parametric definition of the ship hull geometry accurately devised to represent the original hull form solution and to include as many variable shapes and possible, still granting a good fairing of each solution, is described in the paper as well as the technical details of the optimization set up, in terms of high level software architecture; analytical definition of the objective functions; imposition of the design constraints and selection of the optimization strategy. Interesting conclusions are drawn in the end of the paper from the results of the optimization study which showed a good convergence on the optimum solution The numerical results obtained presented in the paper are going to be validated by a series of model tests in towing tak on the original and optimized hull geometry variants.