Feature-based Design Of Sheet-Metal Parts And Research On Some Key Problems

The feature-based modeling method for Sheet-Metal is always an important research area of CAD/CAM. It has achieved great progress and has been widely used in industries over last decade. However, there are still some challenging problems remained. This dissertation focuses on the research on identification and denomination of feature elements and the recognition of intersect features, as well as the related key research issues of feature technology.A new mechanism of naming and identifying topological entities of a feature model is proposed in this thesis, the advantage of the proposed approach is that the identified topological entities are more reasonable in respect to the design intent and it can effectively supported the interacting feature of Sheet-Metal parts.The thesis assorts the feature of Sheet-Metal and uses the approach of feature bintree to store the relation of main features. The structure of the feature tree can reflect the realation between the Sheet-Metal feature clearly and easily, and use the mature algorithom of bintree to get the information of the feature. And it also provides foundation for Sheet-Metal automatic unfolding.The thesis introduces a novel local feature recognition method based on AEAAG (Abstract Extended Attributed Adjacency Graph). AEAAG is used to express the feature model of the Sheet-Metal and the information of topological entities is utilized to generate the assistant edge. Newly generated AEAAG is decomposed and then the interacting features of Sheet-Metals are recognized by matching the subgraph. This method can automatically recognize intersection features of Sheet-Metal parts.A new mechanism which based on the in-order traversing feature binary tree of Sheet-Metal automatic unfolding is proposed in this thesis.Based on all above,we develop a system of SM-CAD (CAD system of Sheet-Metal) which can design the Sheet-Metal easily and unfold the Sheet-Metal automatic.