An Ontology-based Analysis Method On The Impact Of Mechanical Products Engineering Change

It is inevitable for manufacturing enterprises that numerous engineering changes emerge during product design and manufacture. The completed changes are not well employed in most enterprises. And the impact analysis of engineering change mostly depends on experience. It has the disadvantages of low-efficiency, uncompleted analysis results, which even leads to decision-making errors or insufficient change execution implementation. In this paper, engineering change case knowledge ontology was constructed. Retrieval strategy and algorithm of similar change cases were proposed. The change impact was analyzed comprehensively from change impact scope and extent. Change impact scope analysis method was proposed based on product structure relevance, function relevance and external factors relevance. The change impact evaluation system was developed based on cost, time, benefit and risk. The research results of will improve change analysis ability and efficiency of enterprises, as well as market competitive ability in theory and application.Change cases representation method was presented by means of ontology. Combined with the characteristics of change cases, it was abstracted to four basic concepts including change object, change process, change data and change organization. Concept system was established and the concept attributions and relationship among concepts were defined. The unified representation of change cases was realized and the requirement of case reuse was satisfied, which laid foundation for case retrieval and impact analysis.Change cases retrieval strategy was proposed and the modified calculation model was developed based on ontology semantics similarity. The retrieval were transformed to the match between retrieval requirements and change case index, which improved retrieval efficiency. After concept was extended and constraint relationship was defined for retrieval requirement, the vector space model was selected as the retrieval model. The comprehensive similarity value of change cases and retrieval requirements was achieved based on concept attribution similarity. This will ensure the retrieval requirements of users and provide similar change cases rapidly and accurately. Also it will improve the analysis efficiency and quality for users.Analysis method and realization strategy of engineering change impact scope was proposed. Based on the research of change propagation mechanism, change impact scope was analyzed from structure relevance, function relevance and external factors. Search algorithms of graph model based on ontology was used to determine the affected product/component object, drawing and documents data, as well as responsible person and process/activity. It will give a comprehensive and consistent basis for further analysis of impact extent, change decision-making and change implementation.Evaluation system was constructed for engineering change impact extent. Evaluation index system was developed including change cast, change time, change benefit and change risk. The achievement method of index values and calculation method was presented as well as comprehensive evaluation principle of change impact extent. The changeThe evaluation index can be subdivided according to different types change activities for engineering change managers. Change implementation can be evaluated from concerning aspect for prediction and decision-making.The engineering change impact analysis system was designed and realized based on above theoretical and method research. This system was developed based on a product life cycle management platform. By using of this system, change cases, design knowledge and related domain knowledge were retrieved. The change impact scope was analyzed based on ontology. And the change impact extent was analyzed based on cost, time, benefit and risk. The system was verified by automobile parts change case.