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https://hdl.handle.net/10784/29295

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Examinando Artículos por Autor "Barbosa, J."

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    Full scale fatigue test performed to the bolster beam of a railway vehicle
    (Springer-Verlag France, 2018-02-01) Gutiérrez-Carvajal, R.E.; Betancur, G.R.; Barbosa, J.; Castañeda, L.F.; Zaja¸c, G.; Gutiérrez-Carvajal, R.E.; Betancur, G.R.; Barbosa, J.; Castañeda, L.F.; Zaja¸c, G.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecatrónica y Diseño de Máquinas
    Many structural elements are exposed to conditions of load that are difficult to consider during the design stage, such as environment uncertainties, random impacts, overloads and inherent material idealization amongst others, hence, miss-estimating its life-time cycle. One way to test those designs is to construct a representative full-scale specimen and test it under the most critical load conditions in a controlled laboratory. Herein, we present a case of study of the fatigue test performed over a bolster beam redesigned in Universidad EAFIT belonging to a railway vehicle. The test was composed by three stages, each one testing a different load hypothesis. The bolster beam was instrumented at the most critical locations, following the results of a FEM analysis previously computed. As results, the most critical welds were identified and the total damage computed for an equivalent operation of eighteen-years, and also the behaviour of the specimen in presence of extreme longitudinal loads. © 2016, Springer-Verlag France.
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    Hydraulic and rotor-dynamic interaction for performance evaluation on a Francis turbine
    (Springer-Verlag France, 2017-08-01) Garcia, M.; Laín, S.; Orrego, S.; Barbosa, J.; Quintero, B.; Garcia, M.; Laín, S.; Orrego, S.; Barbosa, J.; Quintero, B.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecatrónica y Diseño de Máquinas
    This paper proposes a new methodology to evaluate the technical state of a Francis turbine installed in a hydroelectric plant by coupling computational fluid dynamics (CFD) and rotor-dynamic analysis. CFD simulations predicted the hydraulic performance of the turbine. The obtained field forces, due to the fluid-structure interaction over the blades of the runner, were used as boundary condition in the shaft rotor-dynamic numerical model, which accurately predicted the dynamic behavior of the turbine's shaft. Both numerical models were validated with in situ experimental measurements. The CFD model was validated measuring the pressure fluctuations near the rotor-stator interaction area and the torque and radial force in the shaft using strain gages. The rotor-dynamic model was validated using accelerometers installed over the bearings supporting the shaft. Results from both numerical models were in agreement with experimental measurements and provided a full diagnose of the dynamic working condition of the principal systems of the turbine. Implementation of this methodology can be applied to further identify potential failure and improve future designs.