ESTABLISHMENT OF EFFECTIVE METAMODELS FOR SEAKEEPING PERFORMANCE IN MULTIDISCIPLINARY SHIP DESIGN OPTIMIZATION

Ship design is a complex multidisciplinary optimization process to determine configuration variables that satisfy a set of mission requirements. Unfortunately, high fidelity commercial software for the ship performance estimation such as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) is computationally expensive and time consuming to execute and deters the ship designer's ability to explore larger range of optimization solutions. In this paper, the Latin Hypercube Design was used to select the sample data for covering the design space. The percentage of downtime, a comprehensive seakeeping evaluation index, was also used to evaluate the seakeeping performance within the short-term and long-term wave distribution in the process of Multidisciplinary Design Optimization (MDO). The five motions of ship seakeeping performance contained roll, pitch, yaw, sway and heave. Particularly, a new effective approximation modelling technique Single-Parameter Lagrangian Support Vector Regression (SPL-SVR) was investigated to construct ship seakeeping metamodels to facilitate the application of MDO. By considering the effects of two ship speeds, the established metamedels of ship seakeeping performance for the short-term percentage of downtime are satisfactory for seakeeping predictions during the conceptual design stage; thus, the new approximation algorithm provides an optimal and cost-effective solution for constructing the metamodels in MDO process.