Abstract:To improve the efficiency of ship modeling and provide an original data model for CAE analysis and Structure Design Program (SDP) checking, a ship CAD system for the audit process is designed and developed. By considering the needs of the audit process, both the geometry and the data of the ship model are described, with all ship structures represented by zero-thickness sheet body. Besides, a three-laminated panel model including release model, master model and tool model is established to record the geometric relationship between the panel and its subsidiary structures in the form of panel attributes. The panel and its subsidiary structures are managed by combining the custom structure navigation tree and the assembly tree, the feature tree of the generic 3D modeling software NX. Furthermore, for storing and managing the ship′s standard data and ensuring inquiry efficiency, a standard library system for the whole life cycle is designed based on a lightweight database named SQLite. Finally, the ship model is generated quickly by parametric modeling and structural modeling based on custom feature technology. It is verified that the system proposed in this paper has strong interactivity and stability, and the modeling efficiency is improved with smaller amount of data. After the data conversion, the CAD model can be used directly by CAE and SDP, thus avoiding repetitive design. The use of database technology achieves data sharing between CAD, CAE and SDP modules and solves the problem of data inconsistent and dispersion. The custom structure navigation tree meets the requirements of professional ship designers. Keywords: ship CAD; 3D modeling; audit process; parametric modeling; structural modeling 〖FQ(+24mm。22,ZX-W〗收稿日期: 2018-01-04 基金项目: 国家自然科学基金（51609089） 作者简介: 章志兵(1978—）,男,博士,讲师； 柳玉起（1966—）,男,教授,博士生导师通信作者: 柳玉起,E-mail:liuyq@mail.hust.edu.cn 船舶工业的快速发展,使得船舶CAD技术成为缩短设计生产周期、提高产品质量和降低总体成本的有效方法[1-2]. 目前使用较为广泛的船舶三维设计软件主要有 TRIBON、CATIA、IntelliShip、NX、FORAN等[3]. TRIBON虽解决了船舶设计中面临的主要问题,但其软件封闭性较强,三维图形的拓扑造型能力较弱[4]；CATIA自带的模板数量较少,并且没有标准数据库[5]；IntelliShip和NX生成的模型数据量较大,操作、存储不方便并且降低软件的运行速度[6]；FORAN在生成外壳时需要用户输入大量信息,建模效率低[7-8]. 另外,上述软件缺乏对CAE预处理和SDP校核的针对性,不满足审核流程的需求. 基于NX软件开发平台,使用NX/Open MenuScript和NX/Open BlockUI Style进行软件菜单和界面设计,利用NX/Open API语言模块进行船舶CAD系统开发[9-10]. 基于标准数据库[11],通过结构建模和参数化建模方法,采用几何和数据相结合的方式描述船舶模型,使得模型数据量小且建模效率大大提高[12]. 同时面向审核流程,为CAE和SDP模块提供通用的原始数据模型,减少重复设计,实现数据共享. 1船舶CAD系统体系结构
