Reliability analysis of screwed connections in high-speed trains, considering fatigue, corrosion, and imperfect maintenance operations

The reliability of railway equipment is of central interest in the choice of design and maintenance strategies. In high-speed trains, known as TGV, the assembly of mechanical parts is performed by the use of prestressed screws. In order to ensure safe operation of the railway network, the French company SNCF has undertaken a reliability-based analysis of the life cycle of screwed connections. This study aims at establishing a consistent reliability-based methodology for the assessment of equipments subjected to fatigue, corrosion, and imperfect maintenance operations, in order to improve their inspection on the basis of cost and reliability balancing. This methodology incorporates the life cycle of the equipment, including the deterioration modes, the imperfect maintenance operations and the uncertainties in geometry, loading, and material properties. The results of the study show that despite the high resistance regarding the applied load, the connection is still very sensitive to parameter variations: friction, tightening and prestressing. Although the large safety margin in fatigue design, the robustness of screwed connections should be sought when operation and maintenance conditions are considered.