Search

The sensitivity of ship stability performance in waves to geometric variation has been investigated by means of a simulation-based design framework. The study was devoted to assess the influence of hull geometry variations on some stability failure modes, namely, parametric roll (PR) and pure loss of stability (PLS). The application has been developed by using a representative model of a postpanamax container vessel. PR and PLS phenomena have been investigated by the application of secondgeneration intact stability criteria (SGISc). The initial multidimensional design space has been filled by 500 design configurations identified by means of a design of experiments approach. A method developed in-house, combining the subdivision surface and free-form deformation approaches, has been used to create the whole set of design alternatives. The generated design configurations have been assessed analyzing the results derived from application of the first- and the second-level SGIS vulnerability criteria for both the selected stability failure modes. To strengthen the correlation behaviors, the design space has then been further explored by using 10k design configurations exploiting the capabilities of a surrogate model-based approximation, relying on a Gaussian process formulation. The study has been focused on the correlations among the variables and the response functions, i.e., the outcomes of the SGIS vulnerability criteria. The significance, in terms of effects, of each geometry shape variable has been investigated. Results have been discussed in the light of the SGISc structure, to provide further insight into this innovative safety framework for a modern approach to intact stability. [ABSTRACT FROM AUTHOR]

Techniques for shape representation and further modification of a hull surface definitely play a key role in both the design of new buildings and in the optimisation of the existing ones. The simplification of the methods is the goal to reach in order to create useful tools for real applications. A new approach for hull shape modification is proposed. It is based on a combination of the Subdivision Surface technique for hull surface modelling and Free Form Deformation for shape variation. The formal relation between the two methods is established by the Free Form Deformation control volume and the Subdivision Surface control polygon, introducing significant simplification to the definition of the transformation. The new approach is described in detail highlighting its benefits. Its effectiveness is finally proved by an example of application on a real hull shape, where a combination of a local and global modification has been analysed. [ABSTRACT FROM AUTHOR]