| With the development of design method and digital design technology, design for complex products is being carried out toward integration and optimization. Today ,more and more emphasis are being put on integrated analysis, modeling method, multidisciplinary design optimization (MDO) formulations and data management techniques in the design process. With these problems under consideration the author carries out research on designing complex products from the viewpoint of MDO.The main research content and achievements are as follows:1. The theoretical framework of how to conceptually design complex product with MDO method has been established through analysing disciplinary interactions and design requirments of complex product.At the same time features of MDO framework has also been studied deeply. In the end, the applicable form of the theoretical framework can be detemined, namely, it is must integrate such modules as design requirments, traditional design method, MDO solution verification method and software platform as an achievable carrier. In brief, the applicable framework has dinstinctive characters of integration,automation and multidisciplinary optimization.2. In order to eliminate the difficulty of modeling complex product,A process model based on MDO has been established. In this model, the design process is devided into two parallel courses.The first course is ronsponsible to generate structure information for complex product, the second one is used to conceptually design complex product base on MDO. The ontological structures for designing complex product base on MDO can been obtained by defining ontological classes,then, the modeling process can be realized using UML. It shows that ontology and UML are effective ways of modelling the design process of complex product.3. Quantitative comparisons have been carried out with mathematic examples to get selecting rules or useful conclusions for checking MDO formulations during the process of designing complex product.This job is finished by progressively improving maths examples after establishing uniform formulations prototype.Furthermore, by utilizing"decomposition and coordination"theory for designing large scale system, adopting approximation technology and introducing advanced software and database technique, several ways of improving MDO formulations have been illustrated.4. In order to reduce the difficulty of exchanging information during the process of conceptually design complex product based on MDO,the idea of errecting an intellectual,optimized and integrated engineering design environment founded by combining database management module,object-oriented technique and commercial MDO software has been put forward firstly. Secondly, through defining engineering data model, errecting data exchanging and mapping mechanism between object-oriented data model and data tables in relational database, an efficient data management resolvent has been fulfilled to aid in reducing data value confliction and improving data circulation. Finally, the database based design system has been established to realize the whole data flow in the process of conceptually designing complex product based on MDO method.5. As an application example, a kind of hydro-generator which typically represents complex engineering product has been conceptually designed after analysing complex disciplinary couplings among electromagnetic design,ventilation calculations and heat rejection calculations through multidisciplinary analysis. Mathematic model is firstly formed,then proper MDO formulation is selected, finally, by applying the developped software platform for intergrated designing hydro-generator based on MDO, the optimized solution can be obtained and then verified through numerical simulation. It has been showed that All the work in this example has helped to improve hydro-generator's design quality efficiently and the above research job is effective and applicable. |
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