Percorrer por autor "Nava, Eduardo"
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- Thermal buckling on curved and tangent railways: parametric studyPublication . Piloto, Paulo A.G.; Minhoto, Manuel; Rossetto, Diego R.; Nava, EduardoThis study investigates the thermal buckling in railway infrastructures, which can cause derailments and safety risks. The research analyses the influence of various parameters on thermal buckling, focusing on misalignment and ballast resistance. Using a finite element model, curved and tangent tracks are simulated, considering rail sections, sleeper materials, fastener stiffness and initial imperfections. Results demonstrate that ballast resistance is the most critical factor, with compacted ballast increasing buckling temperatures by up to 127%. Additionally, rail imperfections significantly impact temperature increases. A new design guide is proposed for operating conditions under different conditions.
- Thermal instability of railwaysPublication . Nava, Eduardo; Piloto, P.A.G.; Minhoto, Manuel; Rossetto, Diego R.The railway is a widely used mode of land transportation around the world. To ensure passenger comfort and safety, a specific structure is required, consisting of elements that are divided into infrastructure and superstructure. The superstructure encompasses the rails, sleepers, ballast, and fastening materials, which will be addressed in this study. The efficiency and safety of transporting people and goods on the railway depend largely on the behaviour of this superstructure. Under extreme environmental conditions, such as temperature fluctuations, there is a significant risk of thermal buckling of the rails, which can affect the behaviour of the other elements of the superstructure. This study aims to analyze how these various factors affect the occurrence of thermal buckling in railways. The research identifies rail misalignment and the quality of the ballast as the most influential factors in determining buckling temperatures. The study uses a numerical model, validated through experimental results, to conduct a parametric analysis. The parametric study identified ballast strength as the most critical parameter. When comparing the weak ballast condition (no crib ballast) to the complete and compacted ballast, an increase of up to 127% in buckling temperatures was observed. Additionally, it was observed that the initial rail imperfection significantly influences buckling temperatures. On the other hand, the other evaluated parameters such as rail profile and torsional stiffness had only a minimal influence on buckling temperatures.