Abstract: Traditional CAD system lacks the consideration of mechanical constraints, which can not provide designers with an efficient engineering analysis tool with the difficulty of acquiring and reusing the design knowledge. Mechanical constraints are introduced in product design process by physical model, to build a design mechanism integrating physical model with geometric model. Design history information is recorded. After data mining, the acquired design knowledge is respectively expressed by frame, QOC, etc. A design knowledge management system is built for knowledge storage, retrieval, browse and reuse. The integration of mechanical constraints with geometric model enables the accumulation, extraction and reuse of product design knowledge to become agile and natural.

Key words: knowledge acquisition, knowledge representation, knowledge reuse , physical model