The aim of the present Thesis is to develop models for the study of very highfrequency phenomena associated with the coupled dynamics of a railway vehicle with the track. Through these models, this Thesis intends to address squeal noise as a particular case of rolling noise when the train negotiates a small radius curve.Wheel/rail interaction is the predominant source of noise emission in railway operations. Rolling contact couples the wheel and the rail through a very small area, characterised by strongly non-linear and non-steady state dynamics that differentiates rolling noise from any other noise problem. Wheel/rail contact problem is studied based on Kalker's variational theory and the local falling behaviour of the coefficient of friction is introduced by means of a regularisation of Coulomb's law. Its implementation shows that the influence of the falling friction on the creep curves can be assumed negligible, thus rolling contact is finally modelled using a constant coefficient of friction.Flexibility is introduced in railway substructures through the Finite Element (FE) method in order to cover the high-frequency range. This work adopts a rotatory wheelset model that takes computational advantage of its rotational symmetry. It also develops a cyclic flexible rail model that fixes the translational contact force in a spatial point of the mesh through a technique called Moving Element (ME) method. A modal approach is used to reduce significantly the number of degrees of freedom of the global problem and a diagonalisation technique permits to decouple the resulting modal equations of motion in order to reduce the computational requirements of the time integrator.Simulations in curving conditions in the time domain are carried out for constant friction conditions in order to study if the proposed interaction model can reproduce squeal characteristics for different curve radii and coefficients of friction.Keywords: train/track dynamic interaction, rotatory wheelset, cyclic track, wheel/rail rolling contact, falling friction, regularisation of Coulomb's law, Moving Element Method, decoupling techniques, curve squeal. iii ResumenEl objetivo de la presente Tesis es desarrollar modelos para el estudio de fenómenos de muy alta frecuencia asociados a la dinámica acoplada de un vehículo ferroviario con la vía. A través de estos modelos, esta Tesis pretende abordar el fenómeno de los chirridos como un caso particular de ruido de rodadura en condiciones de curva cerrada.La interacción rueda/carril es la fuente predominante de ruido en las operaciones ferroviarias. El contacto es el responsable del acoplamiento entre la rueda y el carril a través de un área muy pequeña caracterizada por una dinámica fuertemente no lineal y no estacionaria. El problema de contacto rueda/carril se estudia mediante la teoría variacional de Kalker y la caída local del coeficiente de fricción se introduce por medio de una regularización de la ley de Coulomb, que muestra que su influencia sobre las curvas de fluencia se puede despre...
This paper presents a virtual test method for structure-borne noise generated from railway running gear. This method combines a number of existing tools to form a system approach. The wheelset and bogie frame are modelled using FEM software Nastran to include details of their construction. The primary springs are simplified to standard CBUSH elements in Nastran with point and transfer stiffness modelled by frequency-dependent complex stiffness, which are tuned against measurements. The wheel-rail contact forces due to roughness excitation are obtained by the wheel-rail interaction tool TWINS. The vibration of the full running gear is simulated in Nastran by applying the wheel-rail contact forces. The forces transmitted to the vehicle body through traction bars and dampers are calculated for predicting structure-borne noise.
La Universitat Politècnica de València (UPV) ha desarrollado problemas que definen competencias transversales y específicas para sus estudios de Grado y Máster y para las diferentes asignaturas. En un contexto ingenieril, la competencia “Creatividad, Innovación y Emprendimento (CT-04)” permite a los estudiantes enfrentarse a problemas de naturaleza técnica.El presente trabajo se focaliza en el diseño de una actividad docente basada en la realización de un proyecto industrial donde se promueve la competencia anterior. Esta actividad se ha realizado durante dos cursos académicos en la asignatura "Diseño y Apliación de Equipos Industriales" (Máster Universitario en Ingeniería Industrial). Los estudiantes se enfrentan a un proyecto abierto con múltiples alternativas y deben proponer soluciones para optimizar procesos industriales. Todos los proyectos tienen que implementar técnicas innovadoras y creativas para proporcionar soluciones técnicas.Los trabajos académicos se evalúan siguiendo una rúbrica que establece criterios objetivos. Analizar estos resultados permite establecer una correlación entre la influencia de la competencia en las calificaciones del proyecto y de la asignatura, determinando que la competencia prepara a los estudiantes para conseguir los objetivos que deben adquirirse en la asignatura. Se requiere profundizar más para establecer si las rúbricas propuestas pueden detectar el grado de adquisición de la competencia.
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