Free surface definition and usage of the ship hull

本课题对船体曲面的定义和使用进行了研究。该项目主要由两部分组成，即船体曲面定义与设计方法和基于精确船体曲面定义的总体布置系统。在船体曲面定义与设计系统中，引入船型特征线来粗略地表示船型。将船体形状特征线定义为划分船体曲面段的线，如侧、底平、舱底圆、前、后自由面。船体表面的整体性质可以通过特征线条来确定。用非均匀有理B-Spline曲线表示自由曲面被认为是最可行的。针对船体曲面局部不一致的问题，引入了自动光顺系统。在总布置系统方面，将船型数据定义为偏移点数据序列，添加总布置人员必需的船体结构数据进行配置，采用面向对象的方法定义总布置设计的数据结构，在三维CAD和面向对象数据库的基础上建立系统。文中定义的数据结构和算法对于总布置系统是有效的，可以表示整个船舶产品模型的一部分。

The ship hull surface definition and usage has been studied in this project. The project consists of major two parts, that is, the hull surface definition and design methodology and the general arrangement system based on the precision hull surface definition.In the hull surface definition and design system, the hull form characteristic lines were introduced to represent hull form roughly. The hull form characteristic lines are defined as lines dividing the hull surface segments such as side and bottom flat, bilge circle, fore and aft free surfaces. The grobal nature of the hull surface could be detemined by the characteristic lines. To represent free surfaces, the Non Uniform Rational B-Spline curves were thought to be most feasible. Automatic fairing system is introduced for the local inconsistency in the hull surface. The system was installed in the 3 dimensional CAD system to exemplify its capability.As for the general arrangement system, the hull form data was difined as sequences of the offset point data, and the hull structure data indispensable for the general arrangemant was added to configure the system, The object oriented methodology was used to define data structure for the general arrangement design and the system was built based on the three dimensional CAD and object oriented database. The data structure and algorhism defined here were shown effective for the general arrangement system and it would present the part of the whole ship product model.The fundamental consideration for the ship hull surface definition and usage has been conducted in this project.