Simulation of the evolution of rail corrugation using a rotating flexible wheelset model

[EN] This paper presents a simulation tool designed for predicting the wear pattern on the running surface of the rails and for studying the evolution of rail corrugation after thousands of wheelset passages. This simulation tool implements a cyclic track model, a rotating flexible wheelset model, a wheel-rail contact model and a wear model. The vehicle-track system is modelled by using a substructuring technique, by which the vehicle, the rails and the sleepers are treated independently of each other and are coupled by the forces transmitted through the wheel-rail contact and the railpad. The vehicle model takes only account of the wheelset since the sprung masses of the vehicle are not relevant in the frequency range analysed. The wheelset model considers the flexibility of the wheelset and the effects associated with rotation. By using the Campbell diagram, two cases have been identified in which the combined effect of two different modes may give rise to higher wheel-rail contact forces and wear. © 2011 Taylor & Francis.The authors gratefully acknowledge the support for this work provided by the Project TRA2010-15669 (Ministerio de Ciencia e Innovacion) and the valuable help of P. Torstensson from Chalmers University, who suggested the use of the Campbell diagram in this investigation.Vila Tortosa, MP.; Fayos Sancho, J.; Baeza González, LM. (2011). Simulation of the evolution of rail corrugation using a rotating flexible wheelset model. Vehicle System Dynamics. 49(11):1749-1769. https://doi.org/10.1080/00423114.2011.552619S17491769491

Dynamics of damped rotating solids of revolution through an Eulerian modal approach

This article presents a technique for modelling the dynamic response of rotating flexible solids with internal modal damping. The method is applicable to solids with geometry of revolution that rotate around their main axis at constant spinning velocity. The model makes use of an Eulerian modal coordinate system which adopts the vibration modes in a non-rotating frame as basis functions. Due to the coordinate system, the technique is particularly suitable for studying the dynamic interaction between rotating solids and non-rotating structures and permits to obtain Frequency Response Functions. The current investigation presents the development of the proposed technique from a previous Lagrangian model, and consequently the mathematical relationships between the two coordinate sets are found. The approach has been adopted to study the dynamics of a simply supported cylinder including damping in order to obtain the receptance function and the modal properties of the rotating solid.The authors gratefully acknowledge the support for this work provided by the Project TRA2010-15669 (Ministerio de Ciencia e Innovacion).Martínez Casas, J.; Fayos Sancho, J.; Denia Guzmán, FD.; Baeza González, LM. (2012). Dynamics of damped rotating solids of revolution through an Eulerian modal approach. Journal of Sound and Vibration. 331(4):868-882. https://doi.org/10.1016/j.jsv.2011.10.003S868882331

New implant to improve the quality of life of people with transfemoral amputations

[EN] Nowadays, the use of prostheses for transfemoral amputees is painful, and users have poor control of leg movements. Still, the possibility to use an exoprostheses has a direct impact on the quality of life of amputees. This paper presents the project developed by TEQUIR to design a new concept of prosthesis that enables amputees to use a prosthetic leg, with a more natural and comfortable support. This innovation will have a direct impact on improving the quality of life of transfemoral amputees.[ES] En la actualidad, el uso de prótesis externas para amputados transfemorales es doloroso y los usuarios tienen un control deficiente de los movimientos de la pierna. Aun así, la posibilidad de emplear una exoprótesis tiene una repercusión directa en la calidad de vida de los amputados. En este artículo se presenta el proyecto desarrollado por TEQUIR para diseñar un nuevo concepto de prótesis que permita a los amputados emplear una pierna ortopédica con un apoyo más natural y confortable. Esta innovación tendrá un impacto directo en la mejora de la calidad de vida de los amputados transfemorales.Proyecto cofinanciado por el Centro de Desarrollo Tecnológico Industrial (CDTI), y por el Programa de Fomento de la Investigación Técnica (PROFIT) 2005 del Ministerio de Industria, Turismo y Comercio.Giménez Pla, JF.; Bresó Peris, MM.; Fayos Sancho, J.; Atienza Vicente, CM.; Solera Navarro, MJ. (2013). Implantes que mejoran la calidad de vida de personas con amputaciones transfemorales. Revista de biomecánica. 60:55-57. http://hdl.handle.net/10251/38521S55576

Analysis of the backward bending modes in damped rotating beams

[EN] This article presents a study of the backward bending mode of a simply supported rotating Rayleigh beam with internal damping. The study analyses the natural frequency behaviour of the backward mode according to the internal viscous damping ratio, the slenderness of the beam and its spin speed. To date, the behaviour of the natural frequency of the backward mode is known to be a monotonically decreasing function with spin speed due to gyroscopic effects. In this article, however, it is shown that this behaviour of the natural frequency may not hold for certain damping and slenderness conditions, and reaches a minimum value (concave function) from which it begins to increase. Accordingly, the analytical expression of the spin speed for which the natural frequency of the backward mode attains the minimum value has been obtained. In addition, the internal damping ratio and slenderness intervals associated with such behaviour have been also provided.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors gratefully acknowledge the financial support of Ministerio de Ciencia, Innovacion y Universidades Agencia Estatal de Investigacion and the European Regional Development Fund (project TRA2017-84701-R), as well as Generalitat Valenciana (project Prometeo/2016/007) and European Commission through the project 'RUN2Rail - Innovative RUNning gear soluTiOns for new dependable, sustainable, intelligent and comfortable RAIL vehicles' (Horizon 2020 Shift2Rail JU call 2017, grant number 777564)Martínez Casas, J.; Denia Guzmán, FD.; Fayos Sancho, J.; Nadal, E.; Giner Navarro, J. (2019). Analysis of the backward bending modes in damped rotating beams. Advances in Mechanical Engineering. 11(4):1-13. https://doi.org/10.1177/1687814019840474S113114Zorzi, E. S., & Nelson, H. D. (1977). Finite Element Simulation of Rotor-Bearing Systems With Internal Damping. Journal of Engineering for Power, 99(1), 71-76. doi:10.1115/1.3446254Ku, D.-M. (1998). FINITE ELEMENT ANALYSIS OF WHIRL SPEEDS FOR ROTOR-BEARING SYSTEMS WITH INTERNAL DAMPING. Mechanical Systems and Signal Processing, 12(5), 599-610. doi:10.1006/mssp.1998.0159Dimentberg, M. F. (2005). Vibration of a rotating shaft with randomly varying internal damping. Journal of Sound and Vibration, 285(3), 759-765. doi:10.1016/j.jsv.2004.11.025Vatta, F., & Vigliani, A. (2008). Internal damping in rotating shafts. Mechanism and Machine Theory, 43(11), 1376-1384. doi:10.1016/j.mechmachtheory.2007.12.009Rosales, M. B., & Filipich, C. P. (1993). Dynamic Stability of a Spinning Beam Carrying an Axial Dead Load. Journal of Sound and Vibration, 163(2), 283-294. doi:10.1006/jsvi.1993.1165Mazzei, A. J., & Scott, R. A. (2003). Effects of internal viscous damping on the stability of a rotating shaft driven through a universal joint. Journal of Sound and Vibration, 265(4), 863-885. doi:10.1016/s0022-460x(02)01256-7Ehrich, F. F. (1964). Shaft Whirl Induced by Rotor Internal Damping. Journal of Applied Mechanics, 31(2), 279-282. doi:10.1115/1.3629598Vance, J. M., & Lee, J. (1974). Stability of High Speed Rotors With Internal Friction. Journal of Engineering for Industry, 96(3), 960-968. doi:10.1115/1.3438468Vila, P., Baeza, L., Martínez-Casas, J., & Carballeira, J. (2014). Rail corrugation growth accounting for the flexibility and rotation of the wheel set and the non-Hertzian and non-steady-state effects at contact patch. Vehicle System Dynamics, 52(sup1), 92-108. doi:10.1080/00423114.2014.881513Glocker, C., Cataldi-Spinola, E., & Leine, R. I. (2009). Curve squealing of trains: Measurement, modelling and simulation. Journal of Sound and Vibration, 324(1-2), 365-386. doi:10.1016/j.jsv.2009.01.048Bauer, H. F. (1980). Vibration of a rotating uniform beam, part I: Orientation in the axis of rotation. Journal of Sound and Vibration, 72(2), 177-189. doi:10.1016/0022-460x(80)90651-3Shiau, T. N., & Hwang, J. L. (1993). Generalized Polynomial Expansion Method for the Dynamic Analysis of Rotor-Bearing Systems. Journal of Engineering for Gas Turbines and Power, 115(2), 209-217. doi:10.1115/1.2906696Hili, M. A., Fakhfakh, T., & Haddar, M. (2006). Vibration analysis of a rotating flexible shaft–disk system. Journal of Engineering Mathematics, 57(4), 351-363. doi:10.1007/s10665-006-9060-3Young, T. H., Shiau, T. N., & Kuo, Z. H. (2007). Dynamic stability of rotor-bearing systems subjected to random axial forces. Journal of Sound and Vibration, 305(3), 467-480. doi:10.1016/j.jsv.2007.04.016Wang, J., Hurskainen, V.-V., Matikainen, M. K., Sopanen, J., & Mikkola, A. (2017). On the dynamic analysis of rotating shafts using nonlinear superelement and absolute nodal coordinate formulations. Advances in Mechanical Engineering, 9(11), 168781401773267. doi:10.1177/1687814017732672Lee, C.-W. (1993). Vibration Analysis of Rotors. Solid Mechanics and Its Applications. doi:10.1007/978-94-015-8173-8Genta, G. (1999). Vibration of Structures and Machines. doi:10.1007/978-1-4612-1450-2Cheng, C. C., & Lin, J. K. (2003). Modelling a rotating shaft subjected to a high-speed moving force. Journal of Sound and Vibration, 261(5), 955-965. doi:10.1016/s0022-460x(02)01374-

Biomechanical analysis of The North Face new running footwear

[EN] Nowadays, one of the most popular sports is running. The footwear is the basic component for running, having a big influence in the sport performance and injury prevention. When a runner selects a pair of running shoes analyzes carefully the features of the diverse models commercialized before buying the ones that best fits his or her needs. The North Face has counted on IBV to analyze the biomechanical behavior of different running footwear models.[ES] Uno de los deportes más populares en la actualidad es la carrera, también conocida por su término anglosajón running. El calzado es un componente básico para la práctica del running, teniendo una gran influencia en el rendimiento y la prevención de lesiones. Cuando un corredor selecciona su calzado analiza al detalle las prestaciones de los distintos modelos para adquirir el que mejor se adapte a sus necesidades. THE NORTH FACE ha contado con los servicios del IBV para analizar el comportamiento biomecánico de diferentes modelos de zapatillas de running.Puigcerver Palau, SA.; Gonzalez Garcia, JC.; Piqueras Fiszman, P.; Medina Ripoll, E.; Ballester Fernandez, A.; Fayos Sancho, J.; Solves Camallonga, C.... (2013). Biomecánica aplicada al nuevo calzado de running de The North Face. Revista de biomecánica. 59:23-26. http://hdl.handle.net/10251/38640S23265

Measuring High Speed Trains Passenger's comfort

[EN] High Speed Trains Passenger¿s comfort is one of the key aspects for railway operators, that have the client as the center of their activities. ALSTOM, with the purpose of considering these needs, has developed, together with IBV, a tool for diagnose the comfort of their vehicles based on experimental studies.[ES] El confort de los pasajeros de alta velocidad es uno de los aspectos de mayor interés de los operadores ferroviarios que tienen al cliente como centro de sus actividades. ALSTOM, con la finalidad de tener en cuenta estas necesidades ha desarrollado, en colaboración con el Instituto de Biomecánica (IBV), una herramienta de diagnóstico del confort de sus vehículos basada en estudios experimentales.Mateo Martínez, B.; Solaz Sanahuja, JS.; Pujol, C.; Altesa Cabanas, J.; Signes Pérez, E.; Garcés Pérez, L.; Fayos Sancho, J.... (2013). Medir el confort en trenes de alta velocidad. Revista de biomecánica. 60:4-6. http://hdl.handle.net/10251/38683S466

Dinámica estructural de cuerpos de revolución rotatorios: aplicación al eje de un vehículo ferroviario

Fayos Sancho, J. (2008). Dinámica estructural de cuerpos de revolución rotatorios: aplicación al eje de un vehículo ferroviario [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1994Palanci

Dynamic model of a railway wheelset for corrugation problem analysis

[EN] In the present work a model of flexible shafts is adapted for modelling the railway wheelset. The dynamic properties of the solid are obtained from a solid finite element model of a real wheelset. The model adopts an Eulerian coordinate set for numerical efficiency. Results of the crossed-receptance and mobility functions are presented, where the excitation is the vertical wheel-rail contact force and the displacement (or velocity) is measured in the wheel-rail contact plane. These results let us know that the gyroscopic effect may contribute to define the wavelength-fixing mechanism in some corrugation problems, even if the train speed is low.This work was sponsored by Projects T79/2006 (Ministerio de Fomento - Metro de Madrid- CDM) and TRA2007-67167 (Ministerio de Educación y Ciencia - FEDER).Vila Tortosa, MP.; Rovira, A.; Fayos Sancho, J.; Baeza González, LM. (2009). Dynamic model of a railway wheelset for corrugation problem analysis. Noise & Vibration Worldwide. 40(11):10-18. doi:10.1260/095745609790251579S1018401

Análisis MEF de una prótesis metacarpo-falángica

Numerical modeling represents a powerful tool that biomechanics experts apply in the development process of joint prostheses. In particular, finite elements method allows identifying the possible failure causes of an implant, considering the load conditions and the characteristics of its materials. The Institute of Biomechanics of Valencia (IBV) carried out a study of the biomechanical behavior of a metacarpophalangeal prosthesis (MCP), to evaluate the effect of volar luxation and ulnar deviation on the prosthesis model.Las técnicas de modelado numérico representan una potente herramienta que los expertos en biomecánica utilizan en el proceso de desarrollo de prótesis articulares. En particular, el método de los elementos finitos permite determinar las posibles causas de fracaso de un implante, teniendo en cuenta las condiciones de carga y las características de los materiales que lo constituyen. El Instituto de Biomecánica de Valencia (IBV) ha realizado un estudio del comportamiento mecánico de una prótesis metacarpo-falángica (MCP), con el fin de determinar el efecto de la luxación palmar y de la desviación cubital sobre el modelo analizado

Evaluación del confort en los asientos de motocicletas

Over the last few years the customization of products has been the target of the "Custom-Fit" project in which a methodology for seat customization has been generated. A new system has been developed to evaluate user comfort and to increase user satisfaction while driving. In the future, consumers will have seats responding to their comfort needs without compromising safety requirements. Customfit project is now in its final year of execution.LA PERSONALIZACIÓN DE PRODUCTOS HA SIDO DURANTE LOS ÚLTIMOS AÑOS EL PRINCIPAL reto del proyecto "Custom-Fit". El proyecto ha permitido desarrollar métodos de captura de la información de los usuarios, mediante técnicas de última generación para la personalización de productos, como asientos de motocicletas de alta cilindrada, prótesis de miembro inferior, implantes dentales y cascos de motocicleta, entre otros. El proceso definido permite rediseñar los productos y optimizar el comportamiento de los materiales utilizados en las zonas de interacción con el usuario con el objetivo de aumentar el confort y la satisfacción global proporcionada por el producto. El proyecto se encuentra en su fase final y se dispone ya de resultados aplicables a nuevos procesos en la personalización de los asientos de las motocicletas