ข้อมูลผลงานวิจัย

This paper presents a simulation study on the dynamic response of a Monoblock prestressed concrete sleeper on ballast under the impact of wheel flat-spot forces. Using DTrack to model force-time histories from wheel flats and ANSYS for structural behavior simulation, the study focuses on Thailand's railway system, adhering to the State Railway of Thailand (SRT) standards for meter-gauge tracks. The study evaluates the effects of wheel flat-spot-induced forces on sleeper performance, analyzing rail seat displacement, midspan deflection, stress distribution, potential cracking risks, and ballast compressive stress. Flat-spot depths of 1 mm, 2 mm, and 3 mm were examined at train velocities ranging from 60 km/h to 150 km/h. The results show a direct correlation between increased flat-spot depth and velocity with greater sleeper displacement and stress levels. Maximum tensile stresses remained below the concrete's tensile strength, confirming the durability of the sleeper design. However, elevated ballast compressive stress at extreme conditions suggests potential long-term risks of settlement. Fatigue analysis was also performed, with fatigue limits of 86.3 kN for negative bending and 205.8 kN for positive bending. The maximum wheel flat-induced force of 155 kN, applied at the rail seat, is below the positive bending fatigue limit, suggesting no immediate failure. The estimated fatigue life of the sleeper exceeds 9 billion cycles, indicating long-term resilience. This study emphasizes the importance of wheel condition monitoring and periodic maintenance to ensure the safety and longevity of the railway system, with recommendations for improved track maintenance and sleeper design.