Knowledge representation and reuse model of civil aircraft structural maintenance cases

Maintenance cases outside the Structural Repair Manual (OSRM) often occur in civil aircraft structural maintenance (CASM) work. At this time, maintenance personnel needs to learn from historical cases to formulate new maintenance plans. Since CASM cases are diverse, empirical, and heterogeneous, we propose a knowledge representation and reuse model for CASM cases. Firstly, the CASM cases domain ontology is established using Web Ontology Language (OWL), and the case similarity index system is proposed. Then, the proposed global similarity measure integrates three local similarity measures related to different attributes. In particular, considering the engineering significance of attributes, a semantic similarity measure based on ontology structure is proposed. Next, the historical case with the highest similarity with the target case is retrieved under the condition of similarity threshold. Finally, using CASM cases from actual engineering scenes, it is verified that the model has higher retrieval accuracy than traditional methods. Our study shows that case-based decisions have essential reference significance for designing OSRM structural maintenance plans.