Dimension Reduction of Solid Models by Mid-Surface Generation

Recently, feature-based solid modeling systems have been widely used in product design. However, for engineering analysis of a product model, an abstracted CAD model composed of midsurfaces is desirable for conditions in which the abstracted model does not affect analysis result seriously. To meet this requirement, a variety of solid abstraction methods such as MAT (medial axis transformation) have been proposed to provide an abstracted CAE model from a solid design model. The algorithm of the MAT approach can be applied to any complicated solid model. However, additional work to trim and extend some parts of the result is required to obtain a practically useful CAE model because the inscribed sphere used in the MAT method generates insufficient surfaces with branches. On the other hand, the mid-surface abstraction approach supports a practical method for generating a two-dimensional abstracted model, even though it has difficulties in creating a mid-surface from some complicated parts. In this paper, we propose a dimension reduction approach on solid models based on the midsurface abstraction approach. This approach simplifies the solid model by abbreviating or removing trivial features first such as the fillet, mounting, or protrusion. The geometry of each face is replaced with mid-patches from the simplified model, and then unnecessary topological entities are deleted to generate a clean abstracted model. Also, additional work, such as extending and stitching mid-patches, completes the generation of a mid-surface model from the patches.