It is always pursued that the excellent ship structure is rapidly designed and modified on the premise of ensuring security in ship engineering. In this paper, design and optimization method for ship structure based on knowledge-based engineering is put forward. Combining knowledge-based engineering with parametric technology, the knowledge base of ship structure design is established and three-dimensional rapid optimal design is achieved. During the design, positions of ship structure components are driven by positional parameters. Scantlings of ship structural components are obtained by mother ships knowledge base and Non-Uniform Rational B-Splines interpolation, according to rules requirements. Main structures are optimized by quantum-behaved genetic algorithm. Examples show that this method achieves knowledge accumulation and reuse, provides design results inspection, and realizes the obtainment of reliable ship structure.
The ship design quality and efficiency affect ship development cycle. As ship design is a complicated process with many laborintensive activities, how to develop and modify the ship structure rapidly is a major problem for ship designers (Yang et al. 2012).
Traditional ship structural design focuses on dealing with data. It is a kind of interactive graphics operation, and the results that designers work out describe only visual shape and size of ship structure, while related knowledge including design idea, expertise, parent ships information, and rules are not reflected. Obviously, it is not convenient for designers to modify and check the design model (Zhao & Kong 2005). To solve this problem, knowledge-based engineering (KBE) method is applied on ship design to integrate design methods, rules, and expertise experience into design process. Based on the related knowledge, system can automatically offer the high-qualified design model rapidly after designers input parameters and requirements.
Currently, KBE is well developed in vehicle and machinery (Jin et al. 2006). However, because of the variety and complication of ship design, application of KBE on ship industry is still at the beginning. University of Rostock in Germany planned the knowledge-based system for ship modeling in research programs, which could obtain design criteria and provide tools from the knowledge base (Zimmermann & Bronsart 2007). Park identified that the expert system can significantly improve the efficiency and quality of the ship design, and integrated design knowledge into design system and achieved a highly flexible design environment (Park & Storch 2002). Lee applied KBE to the general arrangement of the engine room, making full use of engineering knowledge data (Lee & Yeun 2006). Wu proposed knowledge-based modeling for ship overall design to achieve information storage and retrieval (Wu & Shaw 2011). Chen applied KBE on ship deck design (Chen et al. 2010). Cui used KBE on midship section structural design (Cui et al. 2012). Cai developed a midship section design system based on AutoCAD, subdivided transverse section into several modules, and obtained the min-area midship section (Cai et al. 1997).