A Design Method Of Automatic Parameterization For Ship Hull Surface

The effective and immediate reaction between the ship hull design and performancecomputation is getting highlighted while each of them is developed rapidly. Compared withthe traditional repeating and highly interactive working ways, a design method with direct andimmediate feedback is emerged. A parametric design method for ship hull surface is proposedin this paper. It is based on the principle perspectives to form a systematic and direct feedbackbetween the design of ship hull surface and the evaluation, aim at a designing method ascon-venient and comprehensive as possible with as few parameters as possible. The ship hulldesign method is executed in a performance requirement driven way. By given parameters,designers can get the ship hull surface and corresponding performances achieving the designpattern of knowledge-driven. The process consists three parts: modeling of the ship hull,calculation of the resistance performance and the opti-mization design. And the nonlinearprogramming problem composed by the constraint conditions of hull surface is solved by thegenetic algorithm.Chapter1: The research significance and the research status of each part is introduced inthis chapter. The referred subjects include parametric design, computer aided conceptualdesign, computer aided geometric design, ship resistance, opti-mization design and so on. Thecontent includes the research status of parameter and conceptual design, the expression ofship hull, resistance performance and the optimization design.Chapter2: The basic characteristic curves are defined and classified, including sectionalarea curve, half-breadth water line and the sectional curves. Among of them, sectional areacurve and half-breadth water line are defined by B-spline. Section curves are described bypolynomial function.Chapter3: The frame curves of ship hull are further improved with sectional curves abovewater-plane, longitudinal section curve in center plane and deck-side line defined. Thesectional curves are matched by B-splines. And the ship hull surface is generated by B-splinesurface based on the frame, expressed by the parameters of characteristic curves in acontinuous modeling way.Chapter4: On the base of ship hull parametric modeling, the smoothing degree and theresistance are set as the performance assessment to be calculated. The smoothing degree isjudged by the principle of energy. It is set as one of the optimizing objective functions to dealwith. And the resistance is calculated by experience regression formula. Chapter5: The performance of ship hull surface is set as the objective function, whiledescribing equations of curve forms and the given design parameters as the constraintconditions, to form the non-linear optimization problem of ship hull surface and itsperformance. The genetic algorithm is used to seach for the variate value satisfied the designrequirement. And the designer is get feedback of it with surface and performance, decidingthe next design strategy. The design method is applied and illustrated in the actual designpractice.