Graphics Assisted Design Modeling for 2-D Shape Optimization

Shape optimization of structural components is rapidly developing into a usable engineering design tool. Earlier -work was oriented toward proving the techniques on simple, academic test problems. Much as in the case of finite element modeling, most of the effort in carrying out a successful shape optimization design project comes in creating the design model. In this case the design model is a detailed, parameterized description of the geometry to be designed. The capability described in this paper is based upon a boundary-oriented geometrical description with no information about the interior. Although this is the simplest of all possible descriptions and has been shown to work well on less complex problems, a more automated tool was necessary for realistic components. This paper describes an interactive graphics modeling system which creates all of the data necessary to design stamped sheet metal components using optimization. The procedure works as follows: Utilizing an interactive graphics device, the initial design is drawn on the screen based on a rough sketch. As the geometry is being created, design variables and stress constraints are automatically assigned. The final step is to assign loads, boundary conditions and material properties. No additional effort is required to submit the model to be optimized. Fully automatic mesh generation and adaptive refinement are used to analyze the structure at each design iteration. Several realistic parts are shown to demonstrate the capability.