Examinando por Autor "Urda, Pedro"
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Ítem Analysis of the two-point wheel-rail contact scenario using the knife-edge-equivalent contact constraint method(ELSEVIER, 2020) Fernández-Aceituno, Javier; Urda, Pedro; Briales, Eduardo; Escalona, José LuisThis paper presents a rigid contact approach to analyse the two-point wheel-rail contact scenario using the simplified constraint-based contact method called Knife-edge Equivalent Contact method (KEC-method). The proposed approach makes use of the computationally efficient online solution of the KEC constraints, where a single-point rail is in contact with an equivalent wheel profile, and provides an exact relation between the location of the contact points in the equivalent and real profiles. In this context, the two-point contact scenario can be easily dealt by linearly softening the KEC-constraints in the vicinity of the two-point contact, that gives a continuous and unique contact point solution between each wheel-rail pair and avoids finite contact point jumps between tread and flange. This allows an efficient kinematic solution of the two-point contact scenario. However, to properly ac- count for a dynamic equivalence of the two-point contact scenario in the computation of the tangential contact forces, the reaction force acting on the wheel when the contact point lies on the tread-flange transition, is transformed into two contact forces acting on the tread and flange respectively maintaining the resultant equilibrium of forces at the wheel.Ítem Artificial neural networks applied to the measurement of lateral wheel-rail contact force: A comparison with a harmonic cancellation method(ELSEVIER, 2020) Urda, Pedro; Fernández-Aceituno, Javier; Muñoz-Moreno, Sergio; Escalona, José LuisThis paper presents a method for the experimental measurement of the lateral wheel-rail contact force based on Artificial Neural Networks (ANN). It is intended to demonstrate how an Artificial Intelligence (AI) method proves to be a valid alternative to other approaches based on sophisticated mathematical models when it is applied to the wheel-rail contact force measurement problem. This manuscript addresses the problem from a computational and experimental approach. The artificial intelligence algorithm has been experimentally tested in a real scenario using a 1:10 instrumented scaled railway vehicle equipped with a dynamometric wheelset running on a 5-inch-wide track. The obtained results show that the ANN approach is an easy and computationally efficient method to measure the applied lateral force on the instrumented wheel that requires the use of fewer sensors.Ítem Design and manufacture of a scaled railway track with mechanically variable geometry(NATURE RESEARCH, 2022) Chamorro, Rosario; Fernández-Aceituno, Javier; Urda, Pedro; del-Pozo, Enrique; Escalona, José LuisThe objective of this article is to present the design and manufacture of a scaled railroad track to be used as a laboratory track for the study of different railway applications. It could be a guideline for future laboratory railroad tracks. The ideal concept was based on possible future studies and, according to them, design requirements have been specified. The main characteristic of the track is that its geometry can be mechanically modified and irregularities can be introduced under controlled conditions in any kind of track sections: straight, curved and transition ones. Finally, the current installed track is shown and the performed quality controls are described.Ítem Measurement of railroad track irregularities using an automated recording vehicle(ELSEVIER, 2021) Urda, Pedro; Fernández-Aceituno, Javier; Muñoz-Moreno, Sergio; Escalona, José LuisThis paper presents the design, construction and experimental validation of a scaled railway vehicle for the automated and quick survey of the geometry of an experimental scaled track. The method, that can be extended to full scale tracks, validates the measurements of the automated recording vehicle (ARV) by comparison with respect to a precise but slow manual measuring method (MMM). The two-axle vehicle, which is powered by a brushless DC motor, has its leading axle instrumented with a LVDT, an inclinometer, a reflector and a precisIon encoder. These sensors, together with the help of a total station, allow the measurement of the scaled track geometry and its irregularities following an optimization procedure that first determines the ideal track centreline. The ARV has been tested on a scaled track and its measurements are validated with the MMM results showing a good agreement between both approaches.Ítem Railway multibody simulation with the knife-edge-equivalent wheel–rail constraint equations(SPRINGER, 2020) Escalona, José Luis; Fernández-Aceituno, Javier; Urda, Pedro; Balling, OleThis paper describes a new numerical procedure for the modelling and simulation of the wheel–rail contact in railway dynamic simulations. The method is called knifeedge- equivalent contact constraint method, or simply KEC-method. Using this method, the wheel–rail contact is modelled as rigid or constraint-based using a set of kinematic constraints that eliminates one-degree of freedom of relative wheel–rail motion. The KECmethod uses a transformed but equivalent wheel profile in contact with a single-point rail. This equivalent profile has the property of producing the same wheelset-rail relative kinematics as the real wheel–rail profiles. The method can be used efficiently online while achieving better computational times than using contact lookup tables. Compared with existing constraint methods, the KEC-method has the following advantages: (1) simplification of the wheel–rail contact constraints, (2) simplified wheel–rail profiles, (3) online solution of the contact constraints, (4) reduction of the number of surface parameters, and (5) increased computational efficiency. A comparative study with respect to the use of efficient contact lookup tables in the simulation of Metro de Sevilla (metropolitan train in the city of Sevilla) shows that this contact method is appropriate to simulate the dynamics of a railway vehicle efficiently.