Research On The Car Body Side Outer Panel Assistant Design System Based On Catia

In recent years, the demand for automotive products is increasingly diversified and small batched, which makes various car companiss seek continually to improve design efficiency and reduce development costs. The automotive body design of complex parts is a key factor to affect the whole vehicle development cycle. The development of automotive body can be roughly divided into two stages:conceptual design and detailed part design. Although there are many researches on the rapid modeling of automotive body in the conceptual design stage, such as KBE systems and expert systems, which shorten the development cycle to some extent, there are few researches on automotive body parts in the detailed design stage. In this paper, the integral body side outer panel (BSOP) of a car is selected as an example to investigate the application of the rapid modeling method of complex automotive body parts in the detailed structural design stage in order to shorten the design cycle.For the same brand, especially in the same series of cars, there are many typical structures and general features on the body parts. Therefore, much repetitive work will be done if designers cannot reuse effectively the existing design results. The design is based on the hard points and the master sections, which are the outputs of the prior conceptual design and also the inputs of CAD modeling. In addition, for the BSOP’s complex structure, general parametric modeling method cannot realize the rapid improved design.A novel modeling method based on parameterization is presented here. Firstly, the automotive body structures are simplified by removing untypical structures, and then they are divided into several independent parts based on the main sections. On this basis, each part is created by the parametrization method. Finally, the main section database has been built The manual modeling process contains three steps:selecting the section type from the main section database, inputting the parameters and selecting the constraints.A BSOP assistant design system has been prototyped by applying CAA (Component Application Architecture) in CATIA re-developing environment. The main section models are parameterized by program codes, which create the main section database based on the CAA dialog commands. Three functions have been developed including the structure modeling, the parameter editing and the main section database. The modeling function provides a standardized modeling process using the UI guidance. The parameter editing function is developed based on the feature traversal method so that the parameters can be modified easily later. The main section database has been built, which can be easily used to preview or create a separate main section. In addition, the knowledge-based main section database has been developed to manage the existing main section drawings.It is shown that the system can realize successfully the rapid design of automotive body for the similar structures. In addition, the novel modeling method and its prototyping method can be applied to other automotive body parts or structures.