Development of an Optimization Framework for the Design of High Speed Planing Craft

摘要

High speed planing craft play key roles in supporting several critical maritime activities, e.g., coastal surveillance, reconnaissance, life-saving operations, passenger and high value cargo transport. Despite their significant use, formal optimization frameworks have rarely been proposed to deal with their design challenges. In this thesis, an optimization framework for the preliminary design of high speed planing craft is presented. Several case studies of single- and multi-objective formulations of high speed planing craft design problem are solved using state-of-the-art optimization algorithms. The notion of scenario-based design optimization and innovization, i.e. a means to uncover design relations are also discussed.A modular, extensible design optimization framework that allows the analysis tools to be extended or replaced with the desired level of complexity or with the state-of-the-art analysis tools is proposed in this thesis. A validated 3D mathematical model of high speed planing craft hull form has been identified in this thesis. The use of global parametric transformation that preserves surface fairness and allows for the presence of curve discontinuities is incorporated. A suite of three state-of-the-art optimization algorithms, namely NSGA-II, IDEA and SA-EA is incorporated within the framework. The performances of the algorithms are compared using the case studies. Solutions to single-objective minimization of calm water resistance, resistance in a seaway and multi-objective formulations considering minimization of total resistance, vertical impact acceleration and steady turning diameter have been presented. The capability of the framework to capture design trade-offs is illustrated. The case studies are extended to provide for scenario-based design optimization in order to demonstrate the capability of the framework to solve optimization problems based on the ship's operational profile and operating conditions. A concept of innovization, which allows for the automatic discovery of design rules governing optimum hull forms, is introduced. The relationship gathered through the process of innovization is applied as a cheap pseudo-performance indicator within an optimization formulation, where the results compare favourably with the empirical estimate obtained from experimental data. Such extensions are new contributions to the ship design discipline, in which opens up the possibility of the development of optimum design rules for any particular ship class.