Study On CAD/CAE Application In Design Of Automobile Body Panels Drawing Parts

The drawing process is the most important among the automotive body panels forming processes. Most of automobile panels are formed by drawing process and the die face arises from the shape of drawing parts of automotive body panels. So the design of drawing process and dies for the body panels constitutes an important part in the production of automotive body panels. It includes the design of addendum, binder surface, draw bead, die profile radius and punch profile radius and so on.In this paper, five types of section lines are concluded on the design of drawing parts of automotive body panels. Based on the geometrical feature of these section lines and software Unigraphics (UG) , the CAD system of drawing parts of automotive body panels is further developed with VC++6.0. In the CAD system, the library of section lines is established. The addendum can be generated by the section lines from the library. And the section lines controls the shape and dimensions of addendum, location, number and dimensions of draw bead and dimensions of die profile radius or punch profile radius, which makes modifying the die face more convenient.The function of User Define Feature (UDF) of UG is to import some important features into the library of UDF, each of which is called as an element of other parts and the dimension parameter of feature can be easily modified, thus the design of parts is very convenient. The feature that comes from sketch is related to the corresponding sketch, therefore when the parameters of sketch are changed, the feature will be updated correspondingly. Based on the characters of the sketch, some sketches of section lines were imported into the library of UDF, so that the library of section lines which can control the addendum, binder, draw bead, die profile radius and punch profile radius of the CAD system of drawing parts was founded.CAE is the crucial technology in the design of drawing parts of automotive body panels. The forming processes of the body panels can be simulated by finite software, which can examine the shape of parts, forecast the occurrence of cracks, wrinkle, spring back and optimize the parameters of process. In the developed CAD system of drawing parts, the processes can be controlled by parameters, thus the combination of CAD and CAE is much easier. The parameters of process of drawing parts can be conveniently modified in this CAD system based on CAE data.Taking the automotive panel as an example, the developed CAD system was utilized to design the drawing parts; meanwhile the drawing process was simulated by finite element software Dynaform. Based on the output data of Dynaform, the diverse drawing parameters can be modified easily, which makes the design and modificationmore reasonable and convenient.