Method for obtaining the wheel-rail contact location and its application to the normal problem calculation through CONTACT

[EN] This work presents a robust methodology for calculating inter-penetration areas between railway wheel and rail surfaces, the profiles of which are defined by a series of points. The method allows general three-dimensional displacements of the wheelset to be considered, and its characteristics make it especially suitable for dynamic simulations where the wheel-rail contact is assumed to be flexible. The technique is based on the discretization of the geometries of the surfaces in contact, considering the wheel as a set of truncated cones and the rail as points. By means of this approach, it is possible to reduce the problem to the calculation of the intersections between cones and lines, the solution for which has a closed-form expression. The method has been used in conjunction with the CONTACT algorithm in order to solve the static normal contact problem when the lateral displacement of the wheelset, its yaw angle and the vertical force applied in the wheelset centroid are prescribed. The results consist of smooth functions when the dependent coordinates are represented as a function of the independent ones, lacking the jump discontinuities that are present when a rigid contact model is adopted. Example results are shown and assessed for the normal contact problem for different lateral and yaw positions of the wheelset on the track.This work was supported by the financial contribution of the European Union’s Shift2Rail programme (RUN2Rail project, grant number 777564), the Spanish Ministry of Economy, Industry and Competitiveness and the European Regional Development Fund (projects TRA2013-45596-C2-1-R and TRA2017-84701-R).Baeza González, LM.; Thompson, DJ.; Squicciarini, G.; Denia, FD. (2018). Method for obtaining the wheel-rail contact location and its application to the normal problem calculation through CONTACT. Vehicle System Dynamics. 56(11):1734-1746. https://doi.org/10.1080/00423114.2018.1439178S173417465611Garg, V. K., & Dukkipati, R. V. (1984). Wheel–Rail Rolling Contact Theories. Dynamics of Railway Vehicle Systems, 103-134. doi:10.1016/b978-0-12-275950-5.50009-2Wickens, A. H. (1965). The dynamic stability of railway vehicle wheelsets and bogies having profiled wheels. International Journal of Solids and Structures, 1(3), 319-341. doi:10.1016/0020-7683(65)90037-5DE PATER, A. D. (1988). The Geometrical Contact between Track and Wheelset. Vehicle System Dynamics, 17(3), 127-140. doi:10.1080/00423118808968898Yang G. Dynamic analysis of railway wheelsets and complete vehicle systems (PhD thesis). Delft: Delft University of Technology; 1993.Negretti, D. (2012). A third-order approximation method for three-dimensional wheel–rail contact. Vehicle System Dynamics, 50(3), 431-448. doi:10.1080/00423114.2011.595804Shabana AA, Zaazaa KE, Escalona JL, et al. Modeling two-point wheel/rail contacts using constraint and elastic-force approaches. In: Paidoussis MP, editor. ASME 2002 International Mechanical Engineering Congress and Exposition; 2002 Nov 17–22; New Orleans, Louisiana: American Society of Mechanical Engineers, Rail Transportation Division (Publication) RTD, p. 35–50.Netter, H., Schupp, G., Rulka, W., & Schroeder, K. (1998). NEW ASPECTS OF CONTACT MODELLING AND VALIDATION WITHIN MULTIBODY SYSTEM SIMULATION OF RAILWAY VEHICLES. Vehicle System Dynamics, 29(sup1), 246-269. doi:10.1080/00423119808969563Pombo, J., Ambrósio, J., & Silva, M. (2007). A new wheel–rail contact model for railway dynamics. Vehicle System Dynamics, 45(2), 165-189. doi:10.1080/00423110600996017Polach, O. (2010). Characteristic parameters of nonlinear wheel/rail contact geometry. Vehicle System Dynamics, 48(sup1), 19-36. doi:10.1080/00423111003668203Santamaría, J., Vadillo, E. G., & Gómez, J. (2006). A comprehensive method for the elastic calculation of the two-point wheel–rail contact. Vehicle System Dynamics, 44(sup1), 240-250. doi:10.1080/00423110600870337Cuperus, J. L., & Venter, G. (2016). Numerical simulation and parameterisation of rail–wheel normal contact. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 231(4), 419-430. doi:10.1177/0954409716631009Chollet, H., Sébès, M., Maupu, J. L., & Ayasse, J. B. (2013). The VOCO multi-body software in the context of real-time simulation. Vehicle System Dynamics, 51(4), 570-580. doi:10.1080/00423114.2013.768771Pascal, J.-P., & Soua, B. (2016). Solving conformal contacts using multi-Hertzian techniques. Vehicle System Dynamics, 54(6), 784-813. doi:10.1080/00423114.2016.1161201Piotrowski, J., & Chollet, H. (2005). Wheel–rail contact models for vehicle system dynamics including multi-point contact. Vehicle System Dynamics, 43(6-7), 455-483. doi:10.1080/00423110500141144Vollebregt EAH, Weidemann C, Kienberger A. Use of “CONTACT” in multi-body vehicle dynamics and profile wear simulation: initial results. in: S. Iwinicki (Ed.) 22nd International Symposium on Dynamics of Vehicles on Roads and Tracks (IAVSD2011), Manchester: Manchester Metropolitan University; 2011.Liu, B., Bruni, S., & Vollebregt, E. (2016). A non-Hertzian method for solving wheel–rail normal contact problem taking into account the effect of yaw. Vehicle System Dynamics, 54(9), 1226-1246. doi:10.1080/00423114.2016.1196823Kalker, J. J. (1990). Three-Dimensional Elastic Bodies in Rolling Contact. Solid Mechanics and Its Applications. doi:10.1007/978-94-015-7889-9Pombo, J., & Ambrosio, J. (2005). A computational efficient general wheel-rail contact detection method. Journal of Mechanical Science and Technology, 19(S1), 411-421. doi:10.1007/bf02916162Kaiser, I., & Popp, K. (2006). Interaction of elastic wheelsets and elastic rails: modelling and simulation. Vehicle System Dynamics, 44(sup1), 932-939. doi:10.1080/00423110600907675Falomi, S., Malvezzi, M., & Meli, E. (2011). Multibody modeling of railway vehicles: Innovative algorithms for the detection of wheel–rail contact points. Wear, 271(1-2), 453-461. doi:10.1016/j.wear.2010.10.039Meli, E., Magheri, S., & Malvezzi, M. (2011). Development and implementation of a differential elastic wheel–rail contact model for multibody applications. Vehicle System Dynamics, 49(6), 969-1001. doi:10.1080/00423114.2010.504854Burgelman N. The wheel–rail contact problem in vehicle dynamic simulation, in: Railahead Group [PhD thesis]. Technische Universiteit Delft; 2016.Ren, Z., Iwnicki, S. D., & Xie, G. (2011). A new method for determining wheel–rail multi-point contact. Vehicle System Dynamics, 49(10), 1533-1551. doi:10.1080/00423114.2010.539237Yang, X., Gu, S., Zhou, S., Zhou, Y., & Lian, S. (2015). A method for improved accuracy in three dimensions for determining wheel/rail contact points. Vehicle System Dynamics, 53(11), 1620-1640. doi:10.1080/00423114.2015.1066508Johnson, K. L. (1985). Contact Mechanics. doi:10.1017/cbo9781139171731European Standards, Railway applications – testing for the acceptance of running characteristics of railway vehicles – testing of running behaviour and stationary tests, in: EN 14363:2005

Numerical mode matching for sound propagation in silencers with granular material

[EN] This work presents an efficient numerical approach based on the combination of the mode matching technique and the finite element method (FEM) to model the sound propagation in silencers containing granular material and to evaluate their acoustic performance through the computation of transmission loss (TL). The methodology takes into account the presence of three-dimensional (3D) waves and the corresponding higher order modes, while reducing the computational expenditure of a full 3D FEM calculation. First, the wavenumbers and transversal pressure modes associated with the silencer cross section are obtained by means of a two-dimensional FEM eigenvalue problem, which allows the consideration of arbitrary transversal geometries and material heterogeneities. The numerical approach considers the possibility of using different filling levels of granular material, giving rise to cross sections with abrupt changes of properties located not only in the usual central perforated passage, but also in the transition between air and material, that involves a significant change in porosity. After solving the eigenvalue problem, the acoustic fields (acoustic pressure and axial velocity) are coupled at geometric discontinuities between ducts through the compatibility conditions to obtain the complete solution of the wave equation and the acoustic performance (TL). The granular material is analysed as a potential alternative to the traditional dissipative silencers incorporating fibrous absorbent materials. Sound propagation in granular materials can be modelled through acoustic equivalent properties, such as complex and frequency dependent density and speed of sound. TL results computed by means of the numerical approach proposed here show good agreement with full 3D FEM calculations and experimental measurements. As expected, the numerical mode matching outperforms the computational expenditure of the full 3D FEM approach. Different configurations have been studied to determine the influence on the TL of several parameters such as the size of the material grains, the filling level of the chamber, the granular material porosity and the geometry of the silencer cross section.Project supported by a 2016 BBVA Foundation, Spain Grant for Researchers and Cultural Creators. The BBVA Foundation takes no responsibility for the opinions, remarks or content included in the project and/or the results thereof, which are the sole responsibility of the authors. Support of Generalitat Valenciana (Conselleria d'Educacio, Investigacid, Cultura i Esport), Spain through project Prometeo/2016/007 is also acknowledged.Sánchez Orgaz, EM.; Denia Guzmán, FD.; Baeza González, LM.; Kirby, R. (2019). Numerical mode matching for sound propagation in silencers with granular material. Journal of Computational and Applied Mathematics. 350:233-246. https://doi.org/10.1016/j.cam.2018.10.030S233246350Denia, F. D., Sánchez-Orgaz, E. M., Martínez-Casas, J., & Kirby, R. (2015). Finite element based acoustic analysis of dissipative silencers with high temperature and thermal-induced heterogeneity. Finite Elements in Analysis and Design, 101, 46-57. doi:10.1016/j.finel.2015.04.004Astley, R. J. (1996). FE mode-matching schemes for the exterior Helmholtz problem and their relationship to the FE-DtN approach. Communications in Numerical Methods in Engineering, 12(4), 257-267. doi:10.1002/(sici)1099-0887(199604)12:43.0.co;2-8Glav, R. (1996). THE POINT-MATCHING METHOD ON DISSIPATIVE SILENCERS OF ARBITRARY CROSS-SECTION. Journal of Sound and Vibration, 189(1), 123-135. doi:10.1006/jsvi.1996.0009GLAV, R. (2000). THE TRANSFER MATRIX FOR A DISSIPATIVE SILENCER OF ARBITRARY CROSS-SECTION. Journal of Sound and Vibration, 236(4), 575-594. doi:10.1006/jsvi.2000.2994Kirby, R. (2003). Transmission loss predictions for dissipative silencers of arbitrary cross section in the presence of mean flow. The Journal of the Acoustical Society of America, 114(1), 200-209. doi:10.1121/1.1582448Kirby, R. (2009). A comparison between analytic and numerical methods for modelling automotive dissipative silencers with mean flow. Journal of Sound and Vibration, 325(3), 565-582. doi:10.1016/j.jsv.2009.03.032Fang, Z., & Ji, Z. L. (2014). Numerical Mode Matching Approach for Acoustic Attenuation Predictions of Double-Chamber Perforated Tube Dissipative Silencers with Mean Flow. Journal of Computational Acoustics, 22(02), 1450004. doi:10.1142/s0218396x14500040Yang, L., Ji, Z. L., & Wu, T. W. (2015). Transmission loss prediction of silencers by using combined boundary element method and point collocation approach. Engineering Analysis with Boundary Elements, 61, 265-273. doi:10.1016/j.enganabound.2015.08.004Denia, F. D., Sánchez-Orgaz, E. M., Baeza, L., & Kirby, R. (2016). Point collocation scheme in silencers with temperature gradient and mean flow. Journal of Computational and Applied Mathematics, 291, 127-141. doi:10.1016/j.cam.2015.02.007Kirby, R. (2008). Modeling sound propagation in acoustic waveguides using a hybrid numerical method. The Journal of the Acoustical Society of America, 124(4), 1930-1940. doi:10.1121/1.2967837Denia, F. D., Martínez-Casas, J., Carballeira, J., Nadal, E., & Fuenmayor, F. J. (2018). Computational performance of analytical methods for the acoustic modelling of automotive exhaust devices incorporating monoliths. Journal of Computational and Applied Mathematics, 330, 995-1006. doi:10.1016/j.cam.2017.03.010Allard, J. F., & Atalla, N. (2009). Propagation of Sound in Porous Media. doi:10.1002/9780470747339Li, J., Zhao, S., & Ishihara, K. (2013). Study on acoustical properties of sintered bronze porous material for transient exhaust noise of pneumatic system. Journal of Sound and Vibration, 332(11), 2721-2734. doi:10.1016/j.jsv.2012.12.031Cobo, P., & Simón, F. (2016). A comparison of impedance models for the inverse estimation of the non-acoustical parameters of granular absorbers. Applied Acoustics, 104, 119-126. doi:10.1016/j.apacoust.2015.11.006Kirby, R., & Lawrie, J. B. (2005). A point collocation approach to modelling large dissipative silencers. Journal of Sound and Vibration, 286(1-2), 313-339. doi:10.1016/j.jsv.2004.10.016Murphy, J. E., & Chin‐Bing, S. A. (1989). A finite‐element model for ocean acoustic propagation and scattering. The Journal of the Acoustical Society of America, 86(4), 1478-1483. doi:10.1121/1.398708Pierce, A. D. (1990). Wave equation for sound in fluids with unsteady inhomogeneous flow. The Journal of the Acoustical Society of America, 87(6), 2292-2299. doi:10.1121/1.399073Selamet, A., & Ji, Z. L. (1998). ACOUSTIC ATTENUATION PERFORMANCE OF CIRCULAR EXPANSION CHAMBERS WITH OFFSET INLET/OUTLET: I. ANALYTICAL APPROACH. Journal of Sound and Vibration, 213(4), 601-617. doi:10.1006/jsvi.1998.1514Selamet, A., Xu, M. B., Lee, I.-J., & Huff, N. T. (2005). Analytical approach for sound attenuation in perforated dissipative silencers with inlet/outlet extensions. The Journal of the Acoustical Society of America, 117(4), 2078-2089. doi:10.1121/1.1867884Denia, F. D., Selamet, A., Fuenmayor, F. J., & Kirby, R. (2007). Acoustic attenuation performance of perforated dissipative mufflers with empty inlet/outlet extensions. Journal of Sound and Vibration, 302(4-5), 1000-1017. doi:10.1016/j.jsv.2007.01.005Payri, F., Broatch, A., Salavert, J. M., & Moreno, D. (2010). Acoustic response of fibrous absorbent materials to impulsive transient excitations. Journal of Sound and Vibration, 329(7), 880-892. doi:10.1016/j.jsv.2009.10.015P. Glover, Petrophysics MSc Course Notes, MSc Lecture Notes, University of Leeds

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

Rolling noise reduction through GA-based wheel shape optimization techniques

[EN] Railway rolling noise is nowadays a major source of acoustic pollution in urban areas, with nearly up to 12 million people daily affected in Europe by this phenomenon [1]. Hence, the search for ways of decreasing such noise radiation has become a highly active and significant research field. Following this approach, a Genetic Algorithms-based shape optimization of the railway wheel [2] is developed with the aim of minimizing rolling noise. Different approaches are considered to address the problem, such as directly minimizing radiated Sound poWer Level (SWL) or using the maximization of the natural frequencies if computational efficiency is especially critical. A parametric Finite Element model is implemented for the wheel based on the most relevant geometric parameters in rolling noise radiation. For the acoustic calculation, the sound radiation models used in the TWINS software [3] are adopted, which also accounts for the whole dynamics of the wheel/rail system. Furthermore, for every candidate wheel proposed, a structural analysis is computed in order to check design feasibility in accordance with the corresponding standard [4]. In all cases, new geometries for the wheel cross section are achieved that reduce the radiated rolling noise.This study has been supported by the Agencia Estatal de Investigación and the European Regional Development Fund (project TRA2017-84701-R).Garcia-Andrés, X.; Gutiérrez-Gil, J.; Andrés, VT.; Martínez-Casas, J.; Denia, FD. (2022). Rolling noise reduction through GA-based wheel shape optimization techniques. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 304-312. https://doi.org/10.4995/YIC2021.2021.12577OCS30431

Assessment of oral and written communication competences in the European Higher Education Area: a proposal of evaluation methodologies

[EN] he international accreditation for the Master and Bachelor degrees offered at our university, together with the demands of the employers, have made it clear that the students’ curricula should specify not only what they have studied, but also what they are actually able to do. Although the competence based curricula approach has been used in the development of the new programmes for the Master and Bachelor degrees within the European Higher Education Area in recent years, the assessment of these competences is still a pending task. This work presents an ‘outcomes’ approach for the assessment of the oral and written communication skills within subjects related to mechanical and materials engineering. In particular, this paper proposes some rubrics developed in order to quantify the level of achievement. These rubrics are based on the evaluation of some learning outcomes that can be observed by using different strategies during the course. Conclusions about preliminary results and the difficulties found in order to create these tools are also described here.Sonseca, A.; Sahuquillo, O.; Martinez-Casas, J.; Carballeira, J.; Denia Guzmán, FD.; Rodenas, J.; Rodenas (2015). Assessment of oral and written communication competences in the European Higher Education Area: a proposal of evaluation methodologies. En 1ST INTERNATIONAL CONFERENCE ON HIGHER EDUCATION ADVANCES (HEAD' 15). Editorial Universitat Politècnica de València. 2-9. https://doi.org/10.4995/HEAD15.2015.485OCS2

Assessment of problem-solving skills in subjects related to mechanical and materials engineering

[EN] The international accreditation for the Master and Bachelor degrees offered at our university, together with the demands of the employers, have made it clear that students’ curricula should specify not only what they have studied, but also what they are actually able to do. Although the competence based curricula approach has been used in the development of the new programmes for Master and Bachelor degrees within the European Higher Education Area in recent years, the assessment of generic competences is still a pending task. This work presents an ‘outcomes’ approach for the assessment of the problem-solving capacity in subjects related to mechanical and materials engineering. In particular, this paper proposes a scale in order to quantify the level of achievement and shows some tools developed for this purpose. These tools are based on the evaluation of some learning outcomes that can be observed by using different strategies during the course. Conclusions about preliminary results and the difficulties found in order to create these tools and the scale are also described here.The authors acknowledge the financial contribution of Universitat Politècnica de València through the project PIME/2014/A/012/B.Martínez Casas, J.; Sahuquillo, O.; Sonseca Olalla, A.; Carballeira, J.; Denia Guzmán, FD.; Marco Alacid, O. (2015). Assessment of problem-solving skills in subjects related to mechanical and materials engineering. En 1ST INTERNATIONAL CONFERENCE ON HIGHER EDUCATION ADVANCES (HEAD' 15). Editorial Universitat Politècnica de València. 288-295. https://doi.org/10.4995/HEAD15.2015.48628829

Use of a PBL-approach to develop and to assess generic competences in a Master's degree in Mechanical Engineering

[EN] This paper presents the work carried out within the framework of an educational innovation and improvement project developed during the last two years in the Master's Degree in Mechanical Engineering at the Technical University of Valencia (UPV). One of the main objectives of this project is the development and implementation of new methodologies for the evaluation of generic competences. Among these new methodologies, there is an approach through project-based learning, which allows for the incorporation of the assessment of some generic competences that was not done previously in a proper way. Therefore, several subjects have been coordinated, a new type of Master¿s Thesis has been proposed, with the collaboration of a company, and new assessment tools have been designed.The authors acknowledge the financial contribution by the Universitat Politècnica de València through the project PIME/2018/DPTO.IMM.Carballeira, J.; Tur Valiente, M.; Besa Gonzálvez, AJ.; Albelda Vitoria, J.; Tarancón Caro, JE.; Martínez Casas, J.; Denia Guzmán, FD.... (2020). Use of a PBL-approach to develop and to assess generic competences in a Master's degree in Mechanical Engineering. IATED Academy. 4913-4916. https://doi.org/10.21125/edulearn.2020.1286S4913491

Virtual test method of structure-borne sound for a metro bogie

[EN] 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.The work presented in this paper has received funding from the Shift2Rail Joint Undertaking under the European Union's Horizon 2020 research and innovation programme under grant agreement no. 777564. The contents of this publication only reflect the authors¿ view and the Joint Undertaking is not responsible for any use that may be made of the information contained in the paper. Provision of vehicle data from CAF Spain is gratefully acknowledged.Xie, G.; Rissman, M.; Bouvet, P.; Liu, X.; Thompson, DJ.; Baeza González, LM.; Moreno, J.... (2021). Virtual test method of structure-borne sound for a metro bogie. Springer Nature. 186-193. https://doi.org/10.1007/978-3-030-70289-2_18186193Thompson, D.: Railway Noise and Vibration: Mechanism, Modelling and Means, 1st edn. Elsevier, Oxford (2009)Thompson, D., Hemsworth, B., Vincent, N.: Experimental validation of the TWINS prediction program for rolling noise, part 1: description of the model and method. J. Sound Vib. 193, 123–135 (1996)Report: Deliverable 4.2 – Complete virtual test method for structure-borne and airborne noise transmission, EU Shift2Rail/H2020 project RUN2rail (2019)MSC NASTRAN Quick reference guide (2018

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-

Propiedades acústicas del hormigón poroso a base de áridos ligeros de arlita y vermiculita

[EN] The use of sustainable materials is becoming a common practice for noise abatement in building and civil engineering industries. In this context, many applications have been found for porous concrete made from lightweight aggregates. This work investigates the acoustic properties of porous concrete made from arlite and vermiculite lightweight aggregates. These natural resources can still be regarded as sustainable since they can be recycled and do not generate environmentally hazardous waste. The experimental basis used consists of different type specimens whose acoustic performance is assessed in an impedance tube. Additionally, a simple theoretical model for granular porous media, based on parameters measurable with basic experimental procedures, is adopted to predict the acoustic properties of the prepared mixes. The theoretical predictions compare well with the absorption measurements. Preliminary results show the good absorption capability of these materials, making them a promising alternative to traditional porous concrete solutions.[ES] El uso de materiales sostenibles se está convirtiendo en una práctica común para la reducción de ruido en las industrias de la edificación e ingeniería civil. Este trabajo investiga las propiedades acústicas de hormigón poroso fabricado a partir de áridos ligeros de arlita y vermiculita. Estos recursos naturales todavía pueden considerarse sostenibles ya que pueden ser reciclados y no generan residuos peligrosos para el medio ambiente. La base experimental utilizada se compone de especímenes de diferente tipo cuyas prestaciones acústicas se evalúan en un tubo de impedancia. Adicionalmente, se ha adoptado un modelo teórico simple para medios porosos granulares, basado en parámetros medibles con procedimientos experimentales básicos, con objeto de predecir las propiedades acústicas de las mezclas preparadas. Las predicciones teóricas muestran una buena concordancia con las medidas de absorción. Los resultados preliminares demuestran la buena capacidad absorbente de estos materiales, haciendo de ellos una alternativa prometedora a las soluciones de hormigón poroso tradicionales.Carbajo San Martín, J.; Esquerdo Lloret, TV.; Ramis Soriano, J.; Nadal Gisbert, AV.; Denia Guzmán, FD. (2015). Acoustic properties of porous concrete made from arlite and vermiculite lightweight aggregates. Materiales de Construcción. 65(320):1-11. doi:10.3989/mc.2015.01115S11165320Tutikian, B. F., Nunes, M. F. O., Leal, L. C., & Marquetto, L. (2012). Hormigón ligero con agregado reciclado de EVA para atenuación del ruido de impacto. Materiales de Construcción, 63(310), 309-316. doi:10.3989/mc.2012.06911Krezel, Z. A., & McManus, K. (2000). Recycled aggregate concrete sound barriers for urban freeways. Waste Management Series, 884-892. doi:10.1016/s0713-2743(00)80097-5Kim, H. K., & Lee, H. K. (2010). 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