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Lack of explicit semantics in the product data to be exchanged among product development systems is a major problem for existing product data exchange standards. To solve this problem, the semantics of product data should be enriched to form a basis for exchanging them. This paper proposes an ontology-based approach to enrich the semantics of variational geometric constraint data, one of the most important kinds of product data in product development systems. In this approach, an ontology for variational geometric constraint specifications is constructed by formalizing the specifications in the variational geometric constraint network theory in Web Ontology Language 2 Description Logic (OWL 2 DL) and Semantic Web Rule Language (SWRL). This ontology has rigorous computer-interpretable semantics due to the mathematic logic-based semantics of OWL 2 DL and SWRL. It is capable of providing a semantic enrichment model for the variational geometric constraint data extracted from CAD systems. The ontology is implemented with the use of the OWL 2 DL/SWRL ontology based technologies. As the benefits of the implemented ontology, consistency checking, knowledge reasoning and semantic queries can be automatically performed. These benefits will lay a basis for further exchanging the explicit semantics of variational geometric constraint data among heterogeneous product development systems. [ABSTRACT FROM AUTHOR]

Abstract: There is a critical requirement for semantic interoperability among heterogeneous computer-aided tolerancing (CAT) systems with the sustainable growing demand of collaborative product design. But current data exchange standard for exchanging tolerance information among these systems can only exchange syntaxes and cannot exchange semantics. Semantic interoperability among heterogeneous CAT systems is difficult to be implemented only with this standard. To address this problem, some meta-models of tolerance information supporting semantic interoperability and an interoperability platform based on these meta-models should be constructed and developed, respectively. This paper mainly focuses on the construction of a meta-model for assembly tolerance types with a description logic based approach. Description logics, a family of knowledge representation languages for authoring ontologies, are well-known for having rigorous logic-based semantics which supports semantic interoperability. can provide a formal method to describe the research objects and the relations among them. In this formal method, constraint relations among parts, assembly feature surfaces and geometrical features are defined with some assertional axioms, and the meta-model of assembly tolerance types is constructed through describing the spatial relations between geometrical features with some terminological axioms. Besides, can also provide a highly efficient reasoning algorithm to automatically detect the inconsistency of the knowledge base, a finite set of assertional and terminological axioms. With this reasoning algorithm, assembly tolerance types for each pair of geometrical features are generated automatically through detecting the inconsistencies of the knowledge base. An application example is provided to illustrate the process of generating assembly tolerance types. [Copyright &y& Elsevier]