Conceptual Design Of Car Body Accessories Towards CFD

Following internationalization of the automotive manufacture and individuation on the auto sale, development on new vehicle is coming to more important station. As is known to everyone, in the development of a new vehicle, most changes are focused on auto-body while chassis and engine often follow the mature technique. Domestic and foreign automobile production has been proven in practice,vehicle body depends on the development of production capacity, the vehicle replacement in a large extent determined by the body. Vehicle production capacity and the development of production capacity and depend on the vehicle, the vehicle replacement at the same time also to a large extent reflects directly on the vehicle. At the same time, to struggle against the drastic competition coming from the international market, every automotive manufacturer is trying to shorten the development cycle on new vehicle. To sum up, everyone is doing his best to develop and present new vehicle as fast as could with lowest cost.In the traditional auto-body design flow, designers would spend lots of time and energy on reduplicative work between design project's modification and validation. This is a kind of resources waste and the extended development time would even be viral for manufactures. Computer aided technique has brought designers and manufactures out of the embarrassment somewhat. Nowadays, cooperated design with computer aided technique has been implemented in both auto-body design and parts design. All manufactures want to launch products more quickly and cut down the development cost by shorten product development cycle, while designers hope that their design method is more convenient to update or verify the mechanics so that they could go forward quickly. But generally, there are three defects everyone would meet with:High demand on designer's professional knowledge and experience. To take CAD model creation of auto-body and airframe as example, designers must have an amount of interrelated knowledge and lots of experiences to finish the work on such complex structure. Besides these, they should also master a good skill on the CAD software operation to give a satisfied solution.Lots of complicated manual operation. Because auto-body is such a complex structure, designers would do too much manual operation no matter in CAD or CAE situation. Given one parameter changed, a lot of correlative work would wait in the following sequence. So, even a skillful and experienced designer would waste his time on these repeated operations.Hard to save and reuse knowledge and experience. A skillful and experienced designer often derived from long time effort and mass of resources. Once the designer left, his knowledge and experiences would follow him and left nothing for the replace. This is of course resources waste and apparently increases product's development cost.Based on discuss above, it could be said how to reuse knowledge is becoming more important. This is exactly what KBE (Knowledge based Engineer) tries to answer. UG provided by the fuzzy knowledge-driven automation design, engineering, geometric modeling and the line between programming.Outside rearview mirror and a rear spoiler car body panels are the two most representative accessories subsystems, and related to the knowledge and the factors for consideration will be more, its modular system design and layout is a more troublesome work. So in the module prior to the development of a model to the corresponding simplification, here is mainly directed against CFD analysis. "Conceptual design of car body accessories towards CFD" is based on UG Knowledge Engineering, and the CFD analysis of a software module system. It can help the general design of a fast car body design of the accessories, so that they become simplified design, and rapid. There are three main advantages in the module:Application of Wizard UI (User Interface): Wizard UI delivers knowledge on the system design into different"Steps", designers could finish the design work following the UI steps even without knowing why. It loosens the requirement on designers'professional knowledge.Easy for operation: Only work left for designers is selecting geometries and inputting parameters according the cue on step dialog. All other work such as calculation, measure and modeling is finished automatically behind UI. By reducing manual interactive, the module shortens development cycle greatly. In this "Conceptual design of car body accessories towards CFD" module, UGS provide a development platform Unit environment for completion.Comprehensive use of the C language, UG / Open, UG / UIStyler and UG / Wizard UI, and other development tools. First designers to design requirements, and then by the author of the manual is given to the results of relevant amendments, and then from the revised design on the basis of a viable given the new design, through repeated changes to determine the final package. According to the software engineering development process, the completion of requirements specification (RS), the functional specification (FS) and Design Manual (DS), begin programming work. Finally, the correlative designers give the test on the module functionality.This module for CFD, therefore, used some of aerodynamics knowledge. We have used their own development of the module, the accessories to the car body model made improvements to the CFD analysis, the results obtained and to improve before doing the corresponding comparison.The development of the module follows UG/NX third-party development standards. Although only for the mirrors and the rear spoiler of the car body, it considers many factors. Based on the three reasons above, study and development of the module is typical and would be useful for the others associated development.