Advances Techniques for Time-Domain Modelling of High-Frequency Train/Track Interaction

[EN] The aim of the present Thesis is to develop models for the study of very high-frequency phenomena associated with the coupling 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 increase the computational velocity 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.[ES] El 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 despreciar. Como consecuencia, el coeficiente de fricción se considera constante. La flexibilidad se introduce en las subestructuras ferroviarias a través del método de los Elementos Finitos (EF) para cubrir el rango de las altas frecuencias. La Tesis adopta un modelo de eje montado rotatorio que toma ventaja computacional de su simetría rotacional. También desarrolla un modelo de carril flexible y cíclico que fija la fuerza de contacto en un punto espacial de la malla mediante el método de los Elementos Móviles (EM). Se utiliza un enfoque modal para reducir significativamente el número de grados de libertad del problema global; las ecuaciones de movimiento resultantes en coordenadas modales se desacoplan mendiante una técnica de diagonalización para aumentar la velocidad computacional del integrador temporal. Las simulaciones en condiciones de curva en el dominio del tiempo se llevan a cabo en condiciones de fricción constante con el objetivo de estudiar si el modelo de interacción propuesto puede reproducir las características del chirrido en curva para diferentes radios de curva y coeficientes de fricción.[CAT] L'objectiu de la present Tesi és desenvolupar models per a l'estudi de fenòmens de molt alta freqüència associats amb la dinàmica acoblada d'un vehicle ferroviari amb la via. Aquests models permeten simular el soroll de rodament encara que, en particular, aquest treball es proposa abordar el fenomen del soroll grinyolant produït quan el tren negocia un radi de curvatura estret. La interacció roda/carril és la font predominant de l'emissió de soroll en les operacions ferroviàries. El contacte acobla la roda i el carril a través d'una àrea molt reduïda que es caracteritza per una dinàmica fortament no lineal i no estacionària. El problema de contacte roda/carril s'estudia mitjançant la teoria variacional de Kalker i el descens local del coeficient de fricció s'introdueix per mitjà d'una regularització de la llei de Coulomb, què demostra que la seua influència en les corbes de fluència es pot suposar insignificant. Per tant, s'utilitza un coeficient de fricció constant per a modelar el contacte. La flexibilitat s'introdueix en les subestructures de ferrocarril a través del mètode d'Elements Finits (EF) per tal de cobrir el rang d'alta freqüència. La present tesi adopta un model d'eix muntat rotatori que s'aprofita de la seua la simetria rotacional per a augmentar la eficiència computacional. També desenvolupa un model de carril flexible i cíclic que fixa la força de contacte en un punt espacial de la malla a través del mètode dels Elements Mòbils (EM). S'empra un enfocament modal per reduir significativament el nombre de graus de llibertat del problema global, al temps que s'implementa una tècnica diagonalització que permet desacoblar les equacions modals de moviment per a augmentar la velocitat computacional de l'integrador temporal. Les simulacions en les condicions de corba en el domini del temps es duen a terme per a condicions de fricció constant per tal d'estudiar si el model d'interacció proposat pot reproduir les característiques del soroll grinyolant per a diferents radis de corba i coeficients de fricció.Giner Navarro, J. (2017). Advances Techniques for Time-Domain Modelling of High-Frequency Train/Track Interaction [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90637TESI

On the calculation of the Kalker's creep coefficients for non-elliptical contact areas

[EN] FastSim is the most widely used tangential contact method due to its accuracy and computational efficiency. However, its use is limited to elliptic contact areas, as it needs results from Kalker’s Linear Theory, a Hertzian contact theory, to obtain the so-called elastic parameters. This makes FastSim unable to face some of the current railway challenges, such as wear, corrugation, Rolling Contact Fatigue (RCF), wheel flats, etc. Taking this limitation into account, in the present work, an alternative methodology to Kalker’s Linear Theory is proposed, which will enable FastSim to deal with non-Hertzian conditions.The authors gratefully acknowledge the financial support of Agencia Estatal de Investigación and European Regional Development Fund (grant PRE2018-084067 and project TRA2017-84701-R).Gómez-Bosch, J.; Giner-Navarro, J.; Carballeira, J. (2022). On the calculation of the Kalker's creep coefficients for non-elliptical contact areas. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 288-294. https://doi.org/10.4995/YIC2021.2021.12313OCS28829

Working on Critical Thinking skills using the computer lab works of an Engineering subject

[EN] A practical intervention was devised in order to promote and to assess Critical Thinking in undergraduate students of Engineering. First, in collaboration with specialists in education, the concept of Critical Thinking, and its skills and dispositions on which to focus on, was determined. Second, a teaching strategy was designed in order to be as effective as possible, considering the limitations of the intervention. This strategy took advantage of the computer lab sessions where discussion and questioning encouraged the development of Critical Thinking. Then, the instruments to assess the acquired skills and attitudes of the students were developed. Finally, a quantitative analysis of the results was conducted in order to evaluate the validity and reliability of the strategy. This paper presents a full description of the intervention carried on for two years. Besides the desired effects on the students performance, some conclusions regarding the development of appropriate instruments to deal with a large group of students are drawn. This intervention has proven to be effective in order to help the students to develop their Critical Thinking skills, and it is particularly suitable for large groups.This research was funded by the Universitat Politècnica de València through the project PIME/2018/DPTO. IMM.Giner-Navarro, J.; Sonseca, Á.; Martínez-Casas, J.; Carballeira, J. (2022). Working on Critical Thinking skills using the computer lab works of an Engineering subject. Multidisciplinary Journal for Education, Social and Technological Sciences. 9(2):23-45. https://doi.org/10.4995/muse.2022.1790823459

Optimization of the Perturbation Amplitude for EIS Measurements Using a Total Harmonic Distortion Based Method

[EN] Ohm's generalized law defines the concept of impedance. This law, and thus the definition itself, are only valid if the system fulfills the linearity condition. However, electrochemical systems are typically highly nonlinear. Consequently, the linearity condition can only be achieved in these systems if a low perturbation amplitude is used for performing EIS measurements. Nevertheless, the use of low amplitude perturbations leads to low signal-to-noise ratios, which result in high measurement errors. The concept of optimum amplitude arises from this tradeoff: the perturbation has to have an amplitude big enough in order to minimize the measurement errors (i.e. maximize the SNR), but at the same time, the perturbation has to have an amplitude small enough to avoid the generation of significant nonlinear effects that would distort the measured EIS spectra. In a previous work, a linearity assessment quantitative method based on the total harmonic distortion parameter was developed. In this work, the aforementioned THD method was applied for the perturbation amplitude selection for EIS measurements in a highly nonlinear model system: the cathodic electrode of an alkaline water electrolyzer. The THD method successfully obtained the optimum amplitudes both, for a constant amplitude strategy and for a frequency dependent strategy. The THD method also allowed to obtain the noise structure and to quantify the nonlinear effects. This method is slightly superior to the U-P method, a method based on the harmonic analysis of the output signal that was developed in earlier works. (C) 2018 The Electrochemical Society.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali+d grant (Ref: ACIF-2013-268).Giner-Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2018). Optimization of the Perturbation Amplitude for EIS Measurements Using a Total Harmonic Distortion Based Method. 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Enhancing the Photovoltaic Performance of Dye-Sensitized Solar Cells with Rare-Earth Metal Oxide Nanoparticles. Journal of The Electrochemical Society, 165(3), H52-H56. doi:10.1149/2.1311802jesGong, C., Hong, X., Xiang, S., Wu, Z., Sun, L., Ye, M., & Lin, C. (2018). NiS2Nanosheet Films Supported on Ti Foils: Effective Counter Electrodes for Quantum Dot-Sensitized Solar Cells. Journal of The Electrochemical Society, 165(3), H45-H51. doi:10.1149/2.0171803jesMitra, D., Trinh, P., Malkhandi, S., Mecklenburg, M., Heald, S. M., Balasubramanian, M., & Narayanan, S. R. (2018). An Efficient and Robust Surface-Modified Iron Electrode for Oxygen Evolution in Alkaline Water Electrolysis. Journal of The Electrochemical Society, 165(5), F392-F400. doi:10.1149/2.1371805jesYoon, S., Kim, J., Lim, J.-H., & Yoo, B. (2018). Cobalt Iron-Phosphorus Synthesized by Electrodeposition as Highly Active and Stable Bifunctional Catalyst for Full Water Splitting. 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Combined effects of Tafel kinetics and Ohmic potential drop on the nonlinear responses of electrochemical systems to low-frequency sinusoidal perturbation of electrode potential – New approach using the Lambert W-function. Journal of Electroanalytical Chemistry, 672, 17-27. doi:10.1016/j.jelechem.2012.03.003Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Non-linear impedance for a two-step electrode reaction with an intermediate adsorbed species. Electrochimica Acta, 42(7), 1053-1072. doi:10.1016/s0013-4686(96)00206-xDiard, J.-P., Le Gorrec, B., & Montella, C. (1997). Deviation from the polarization resistance due to non-linearity I - theoretical formulation. Journal of Electroanalytical Chemistry, 432(1-2), 27-39. doi:10.1016/s0022-0728(97)00213-1Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Deviation of the polarization resistance due to non-linearity II. Application to electrochemical reactions. Journal of Electroanalytical Chemistry, 432(1-2), 41-52. doi:10.1016/s0022-0728(97)00234-9Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Deviation of the polarization resistance due to non-linearity. III—Polarization resistance determination from non-linear impedance measurements. Journal of Electroanalytical Chemistry, 432(1-2), 53-62. doi:10.1016/s0022-0728(97)00233-7Diard, J.-P., Le Gorrec, B., & Montella, C. (1994). Impedance measurement errors due to non-linearities—I. Low frequency impedance measurements. Electrochimica Acta, 39(4), 539-546. doi:10.1016/0013-4686(94)80098-7Diard, J.-P., Le Gorrec, B., & Montella, C. (1994). Theoretical formulation of the odd harmonic test criterion for EIS measurements. Journal of Electroanalytical Chemistry, 377(1-2), 61-73. doi:10.1016/0022-0728(94)03624-1Smulko, J., & Darowicki, K. (2003). Nonlinearity of electrochemical noise caused by pitting corrosion. Journal of Electroanalytical Chemistry, 545, 59-63. doi:10.1016/s0022-0728(03)00106-2Darowicki, K. (1997). Linearization in impedance measurements. Electrochimica Acta, 42(12), 1781-1788. doi:10.1016/s0013-4686(96)00377-5Darowicki, K. (1995). The amplitude analysis of impedance spectra. Electrochimica Acta, 40(4), 439-445. doi:10.1016/0013-4686(94)00303-iDarowicki, K. (1995). Frequency dispersion of harmonic components of the current of an electrode process. Journal of Electroanalytical Chemistry, 394(1-2), 81-86. doi:10.1016/0022-0728(95)04065-vVan Gheem, E., Pintelon, R., Hubin, A., Schoukens, J., Verboven, P., Blajiev, O., & Vereecken, J. (2006). Electrochemical impedance spectroscopy in the presence of non-linear distortions and non-stationary behaviour. Electrochimica Acta, 51(8-9), 1443-1452. doi:10.1016/j.electacta.2005.02.096Van Gheem, E., Pintelon, R., Vereecken, J., Schoukens, J., Hubin, A., Verboven, P., & Blajiev, O. (2004). Electrochemical impedance spectroscopy in the presence of non-linear distortions and non-stationary behaviour. Electrochimica Acta, 49(26), 4753-4762. doi:10.1016/j.electacta.2004.05.039Pintelon, R., Louarroudi, E., & Lataire, J. (2015). Nonparametric time-variant frequency response function estimates using arbitrary excitations. Automatica, 51, 308-317. doi:10.1016/j.automatica.2014.10.088Pintelon, R., Louarroudi, E., & Lataire, J. (2013). Detecting and Quantifying the Nonlinear and Time-Variant Effects in FRF Measurements Using Periodic Excitations. IEEE Transactions on Instrumentation and Measurement, 62(12), 3361-3373. doi:10.1109/tim.2013.2267457Popkirov, G. S., & Schindler, R. N. (1995). Effect of sample nonlinearity on the performance of time domain electrochemical impedance spectroscopy. Electrochimica Acta, 40(15), 2511-2517. doi:10.1016/0013-4686(95)00075-pPopkirov, G. S., & Schindler, R. N. (1993). Optimization of the perturbation signal for electrochemical impedance spectroscopy in the time domain. Review of Scientific Instruments, 64(11), 3111-3115. doi:10.1063/1.1144316Giner-Sanz, J. J., Ortega, E. M., & Pérez-Herranz, V. (2015). Total harmonic distortion based method for linearity assessment in electrochemical systems in the context of EIS. Electrochimica Acta, 186, 598-612. doi:10.1016/j.electacta.2015.10.152On the definition of total harmonic distortion and its effect on measurement interpretation. (2005). IEEE Transactions on Power Delivery, 20(1), 526-528. doi:10.1109/tpwrd.2004.839744Mao, Q., & Krewer, U. (2013). Total harmonic distortion analysis of oxygen reduction reaction in proton exchange membrane fuel cells. Electrochimica Acta, 103, 188-198. doi:10.1016/j.electacta.2013.03.194Mao, Q., & Krewer, U. (2012). Sensing methanol concentration in direct methanol fuel cell with total harmonic distortion: Theory and application. Electrochimica Acta, 68, 60-68. doi:10.1016/j.electacta.2012.02.018Mao, Q., Krewer, U., & Hanke-Rauschenbach, R. (2010). Total harmonic distortion analysis for direct methanol fuel cell anode. Electrochemistry Communications, 12(11), 1517-1519. doi:10.1016/j.elecom.2010.08.022Thomas, S., Lee, S. C., Sahu, A. K., & Park, S. (2014). Online health monitoring of a fuel cell using total harmonic distortion analysis. International Journal of Hydrogen Energy, 39(9), 4558-4565. doi:10.1016/j.ijhydene.2013.12.180Garcia-Antón J. Igual-Muñoz A. Guiñon J. L. Pérez-Herranz V. Herraiz-Cardona I. Ortega E. M. , Horizontal cell for electro-optical analysis of electrochemical processes, ES patent P-2000002526, October 2000.Herraiz-Cardona I. , Desarrollo de nuevos materiales de electrodo para la obtención de hidrógeno a partir de la electrolisis alcalina del agua, PhD Tesis, Valencia, Universitat Politècnica de València (2012).Giner-Sanz, J. J., Ortega, E. M., & Pérez-Herranz, V. (2015). Optimization of the electrochemical impedance spectrosc

Harmonic analysis based method for linearity assessment and noise quantification in electrochemical impedance spectroscopy measurements: Theoretical formulation and experimental validation for Tafelian systems

Electrochemical Impedance Spectroscopy (EIS) is an electrochemical measurement technique that has been applied to a broad range of applications. Three conditions must be fulfilled in order to obtain valid EIS measurements: causality, linearity and stationarity. The non fulfilment of any of these conditions may lead to distorted and biased EIS spectra. Consequently, the verification of the four fundamental conditions is mandatory before accepting any results extracted from an EIS spectrum. In this work, a harmonic analysis based method for linearity assessment and noise quantification in EIS measurements is presented, and validated both from an experimental point of view and from a theoretical point of view, for Tafelian systems. It was shown that the presented method was able to quantitatively assess the nonlinearity of the system; and to quantify and characterize the noise. Moreover, the presented method is able to determine the threshold frequency of the system above which the system does not present significant nonlinear effects even for very large perturbation amplitudes.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali+d grant (Ref: ACIF-2013-268).Giner-Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2016). Harmonic analysis based method for linearity assessment and noise quantification in electrochemical impedance spectroscopy measurements: Theoretical formulation and experimental validation for Tafelian systems. Electrochimica Acta. 211:1076-1091. doi:10.1016/j.electacta.2016.06.133S1076109121

Statistical analysis of the effect of temperature and inlet humidities on the parameters of a semiempirical model of the internal resistance of a polymer electrolyte membrane fuel cell

[EN] he internal resistance of a PEM fuel cell depends on the operation conditions and on the current delivered by the cell. This work's goal is to obtain a semiempirical model able to reproduce the effect of the operation current on the internal resistance of an individual cell of a commercial PEM fuel cell stack; and to perform a statistical analysis in order to study the effect of the operation temperature and the inlet humidities on the parameters of the model. First, the internal resistance of the individual fuel cell operating in different operation conditions was experimentally measured for different DC currents, using the high frequency intercept of the impedance spectra. Then, a semiempirical model based on Springer and co-workers¿ model was proposed. This model is able to successfully reproduce the experimental trends. Subsequently, the curves of resistance versus DC current obtained for different operation conditions were fitted to the semiempirical model, and an analysis of variance (ANOVA) was performed in order to determine which factors have a statistically significant effect on each model parameter. Finally, a response surface method was applied in order to obtain a regression model.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Valid grant (Ref:. ACIF-2013-268)Giner-Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2018). Statistical analysis of the effect of temperature and inlet humidities on the parameters of a semiempirical model of the internal resistance of a polymer electrolyte membrane fuel cell. Journal of Power Sources. 381:84-93. https://doi.org/10.1016/j.jpowsour.2018.01.093S849338

A linear non-Hertzian unsteady tangential wheel-rail contact model

[EN] The increase in computational capacity has considerably reduced the use of linear models for wheel/rail tangential contact, being currently replaced by theories that adopt non-linear formulations able to address the most complex conditions realistically. However, linear formulations are difficult to replace in certain applications such as acoustic problem modelling, in which case a linear formulation of the track-contact-vehicle system is needed. The vibration that appears in this type of problem covers a wide range of audible frequencies, so, in addition to linearity, these theories are required to be non-stationary. The literature in contact mechanics gives response to this problem through models that consider low creepage levels, but it remains to cover other conditions in which the mean creepage is not small, such as when a railway vehicle negotiates a curve. This work presents a new theory of unsteady linear tangential rolling contact for non-Hertzian areas that considers kinematics as the sum of a constant creepage resulting from large stationary forces (such as those that occur when the vehicle negotiates a curve with constant radius) and small variable creepage due to a high-frequency phenomenon (e.g. the dynamic interaction between the vehicle and the track). The model is based on the Variational Theory (i.e. the CONTACT method for tangential problems), from which a linear formulation with variable creepage is deduced. According to this formulation, the non-steady state contact problem can be solved for any shape of the wheel/rail contact region, requiring a much smaller computational effort than the general unsteady CONTACT approach. The results show a satisfactory agreement of the proposed model to the unsteady CONTACT version, hence confirming the soundness of the proposed contact model.The first and third authors acknowledge the financial support through the grants PID2020-118013RB-C21 (funded by MCIN/AEI/10.13039/501100011033) and PROMETEO/2021/046 (funded by Generalitat Valenciana).Baeza González, LM.; Bruni, S.; Giner Navarro, J.; Liu, B. (2023). A linear non-Hertzian unsteady tangential wheel-rail contact model. Tribology International. 181:1-10. https://doi.org/10.1016/j.triboint.2023.10834511018

Hydrogen crossover and internal short-circuit currents experimental characterization and modelling in a proton exchange membrane fuel cell

[EN] Open circuit losses encompass a set of phenomena that reduce PEM fuel cell (PEMFC) efficiency, especially at low current densities. Properly modelling these losses is crucial for obtaining PEMFC models that reproduce accurately the experimental behaviour of PEMFCs operating at low current densities. The open circuit losses can be disaggregated into three distinct contributions: mixed potential, hydrogen crossovers and internal short-circuits. The aim of this work is to obtain a model for the anodic and the cathodic pressure effects on the hydrogen crossovers and the internal short-circuits in a commercial PEMFC. In order to achieve this goal, the hydrogen crossovers and the internal short-circuit were measured experimentally on a commercial PEMFC by linear voltammetry. The measurements were performed at a given temperature and gas inlet humidification level, for different anodic and cathodic pressures.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali+d grant (Ref: ACIF-2013-268).Giner-Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2014). Hydrogen crossover and internal short-circuit currents experimental characterization and modelling in a proton exchange membrane fuel cell. International Journal of Hydrogen Energy. 39(25):13206-13216. https://doi.org/10.1016/j.ijhydene.2014.06.157S1320613216392

Harmonic Analysis Based Method for Perturbation Amplitude Optimization for EIS Measurements

[EN] The impedance concept is defined by Ohm's generalized law. Ohm's law requires the fulfilment of 3 conditions in order to be valid: causality, linearity and stability. In general, electrochemical systems are highly nonlinear systems; and therefore, in order to achieve linearity low amplitude perturbations have to be used during EIS measurements. However, small amplitude perturbations lead to low signal-to-noise ratios. Consequently, the quality of an EIS measurement is determined by a trade-off: the perturbation amplitude should be big enough in order to obtain a good signal-to-noise ratio; and at the same time, it should be small enough in order to avoid significant nonlinear effects. The optimum perturbation amplitude corresponds with the maximum perturbation amplitude that ensures a pseudo linear response of the system. In this work, a method for experimentally determining the optimum perturbation amplitude for performing EIS measurements of a given system is presented. The presented method is based on the harmonic analysis of the output signals; and in this work, it was applied to a highly nonlinear system: the cathodic electrode of an alkaline water electrolyser. The presented method allows optimising the perturbation amplitude in both, constant amplitude and frequency dependant amplitude strategies. (c) 2017 The Electrochemical Society. All rights reserved.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali+d grant (Ref: ACIF-2013-268).Giner-Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2017). Harmonic Analysis Based Method for Perturbation Amplitude Optimization for EIS Measurements. Journal of The Electrochemical Society. 164(13):H918-H924. https://doi.org/10.1149/2.1451713jesSH918H92416413Macdonald, D. D. (2006). Reflections on the history of electrochemical impedance spectroscopy. Electrochimica Acta, 51(8-9), 1376-1388. doi:10.1016/j.electacta.2005.02.107Orazem M. E. Tribollet B. , Electrochemical Impedance Spectroscopy, John Wiley & Sons, New Jersey (2008).Giner-Sanz, J. J., Ortega, E. M., & Pérez-Herranz, V. (2015). Montecarlo based quantitative Kramers–Kronig test for PEMFC impedance spectrum validation. International Journal of Hydrogen Energy, 40(34), 11279-11293. doi:10.1016/j.ijhydene.2015.03.135Cascos, V., Aguadero, A., Harrington, G., Fernández-Díaz, M. T., & Alonso, J. A. (2017). Design of Sr0.7R0.3CoO3-δ(R = Tb and Er) Perovskites Performing as Cathode Materials in Solid Oxide Fuel Cells. Journal of The Electrochemical Society, 164(10), F3019-F3027. doi:10.1149/2.0031710jesPang, S., Wang, W., Su, Y., Shen, X., Wang, Y., Xu, K., & Chen, C. (2017). Synergistic Effect of A-Site Cation Ordered-Disordered Perovskite as a Cathode Material for Intermediate Temperature Solid Oxide Fuel Cells. Journal of The Electrochemical Society, 164(7), F775-F780. doi:10.1149/2.0701707jesKiebach, R., Zielke, P., Veltzé, S., Ovtar, S., Xu, Y., Simonsen, S. B., … Küngas, R. (2017). On the Properties and Long-Term Stability of Infiltrated Lanthanum Cobalt Nickelates (LCN) in Solid Oxide Fuel Cell Cathodes. Journal of The Electrochemical Society, 164(7), F748-F758. doi:10.1149/2.0361707jesChen, J., Liu, Q., Wang, B., Li, F., Jiang, H., Liu, K., … Wang, D. (2017). Hierarchical Polyamide 6 (PA6) Nanofibrous Membrane with Desired Thickness as Separator for High-Performance Lithium-Ion Batteries. Journal of The Electrochemical Society, 164(7), A1526-A1533. doi:10.1149/2.0971707jesHwang, C., Lee, K., Um, H.-D., Lee, Y., Seo, K., & Song, H.-K. (2017). Conductive and Porous Silicon Nanowire Anodes for Lithium Ion Batteries. Journal of The Electrochemical Society, 164(7), A1564-A1568. doi:10.1149/2.1241707jesZhang, Y., Chen, F., Yang, D., Zha, W., Li, J., Shen, Q., … Zhang, L. (2017). High Capacity All-Solid-State Lithium Battery Using Cathodes with Three-Dimensional Li+Conductive Network. Journal of The Electrochemical Society, 164(7), A1695-A1702. doi:10.1149/2.1501707jesMalifarge, S., Delobel, B., & Delacourt, C. (2017). Determination of Tortuosity Using Impedance Spectra Analysis of Symmetric Cell. Journal of The Electrochemical Society, 164(11), E3329-E3334. doi:10.1149/2.0331711jesPaulraj, A. R., Kiros, Y., Skårman, B., & Vidarsson, H. (2017). Core/Shell Structure Nano-Iron/Iron Carbide Electrodes for Rechargeable Alkaline Iron Batteries. Journal of The Electrochemical Society, 164(7), A1665-A1672. doi:10.1149/2.1431707jesStein, M., Mistry, A., & Mukherjee, P. P. (2017). Mechanistic Understanding of the Role of Evaporation in Electrode Processing. Journal of The Electrochemical Society, 164(7), A1616-A1627. doi:10.1149/2.1271707jesMurbach, M. D., & Schwartz, D. T. (2017). Extending Newman’s Pseudo-Two-Dimensional Lithium-Ion Battery Impedance Simulation Approach to Include the Nonlinear Harmonic Response. Journal of The Electrochemical Society, 164(11), E3311-E3320. doi:10.1149/2.0301711jesGiner-Sanz, J. J., Ortega, E. M., & Pérez-Herranz, V. (2017). Experimental Quantification of the Effect of Nonlinearities on the EIS Spectra of the Cathodic Electrode of an Alkaline Electrolyzer. Fuel Cells, 17(3), 391-401. doi:10.1002/fuce.201600137Katić, J., Metikoš-Huković, M., Šarić, I., & Petravić, M. (2017). Electronic Structure and Redox Behavior of Tin Sulfide Films Potentiostatically Formed on Tin. Journal of The Electrochemical Society, 164(7), C383-C389. doi:10.1149/2.0371707jesYang, J., Yang, Y., Balaskas, A., & Curioni, M. (2017). Development of a Chromium-Free Post-Anodizing Treatment Based on 2-Mercaptobenzothiazole for Corrosion Protection of AA2024T3. Journal of The Electrochemical Society, 164(7), C376-C382. doi:10.1149/2.1191707jesTakabatake, Y., Kitagawa, Y., Nakanishi, T., Hasegawa, Y., & Fushimi, K. (2017). Grain Dependency of a Passive Film Formed on Polycrystalline Iron in pH 8.4 Borate Solution. Journal of The Electrochemical Society, 164(7), C349-C355. doi:10.1149/2.1011707jesQi, J., Gao, L., Li, Y., Wang, Z., Thompson, G. E., & Skeldon, P. (2017). An Optimized Trivalent Chromium Conversion Coating Process for AA2024-T351 Alloy. Journal of The Electrochemical Society, 164(7), C390-C395. doi:10.1149/2.1371707jesZhang, Q., Kercher, A. K., Veith, G. M., Sarbada, V., Brady, A. B., Li, J., … Marschilok, A. C. (2017). Lithium Vanadium Oxide (Li1.1V3O8) Coated with Amorphous Lithium Phosphorous Oxynitride (LiPON): Role of Material Morphology and Interfacial Structure on Resulting Electrochemistry. Journal of The Electrochemical Society, 164(7), A1503-A1513. doi:10.1149/2.0881707jesMoya, A. A. (2016). Electrochemical Impedance of Ion-Exchange Membranes with Interfacial Charge Transfer Resistances. The Journal of Physical Chemistry C, 120(12), 6543-6552. doi:10.1021/acs.jpcc.5b12087García-Osorio, D. A., Jaimes, R., Vazquez-Arenas, J., Lara, R. H., & Alvarez-Ramirez, J. (2017). The Kinetic Parameters of the Oxygen Evolution Reaction (OER) Calculated on Inactive Anodes via EIS Transfer Functions:•OH Formation. Journal of The Electrochemical Society, 164(11), E3321-E3328. doi:10.1149/2.0321711jesWei, Q., Yan, X., Kang, Z., Zhang, Z., Cao, S., Liu, Y., & Zhang, Y. (2017). Carbon Quantum Dots Decorated C3N4/TiO2Heterostructure Nanorod Arrays for Enhanced Photoelectrochemical Performance. Journal of The Electrochemical Society, 164(7), H515-H520. doi:10.1149/2.1281707jesMachado, S., Calaça, G. N., da Silva, J. P., de Araujo, M. P., Boeré, R. T., Pessôa, C. A., & Wohnrath, K. (2017). Electrochemical Characterization of a Carbon Ceramic Electrode Modified with a Ru(II) Arene Complex and Its Application as Voltammetric Sensor for Paracetamol. Journal of The Electrochemical Society, 164(6), B314-B320. doi:10.1149/2.0191707jesBalasubramanian, P., Thirumalraj, B., Chen, S.-M., & Barathi, P. (2017). Electrochemical Determination of Isoniazid Using Gallic Acid Supported Reduced Graphene Oxide. Journal of The Electrochemical Society, 164(7), H503-H508. doi:10.1149/2.1021707jesJiang, J. (2017). High Temperature Monolithic Biochar Supercapacitor Using Ionic Liquid Electrolyte. Journal of The Electrochemical Society, 164(8), H5043-H5048. doi:10.1149/2.0211708jesWang, K.-Y., Chiu, Y.-K., & Cheng, H.-C. (2017). Electrochemical Capacitors of Horizontally Aligned Carbon Nanotube Electrodes with Oxygen Plasma Treatment. Journal of The Electrochemical Society, 164(7), A1587-A1594. doi:10.1149/2.1251707jesChang, C., Yang, X., Xiang, S., Lin, X., Que, H., & Li, M. (2017). Nitrogen and Sulfur Co-Doped Glucose-Based Porous Carbon Materials with Excellent Electrochemical Performance for Supercapacitors. Journal of The Electrochemical Society, 164(7), A1601-A1607. doi:10.1149/2.1341707jesLasia A. , Electrochemical Impedance Spectrscopy and its applications, Springer, London (2014).Gray M. G. Goodman J. W. , Electrochemical Impedance Spectrscopy and its applications, Springer, New York (1995).Barsoukov E. Macdonald J. R. , Impedance Spectroscopy. Theory, experiment and applications, John Wiley & Sons, New Jersey (2005).Macdonald, D. D., Sikora, E., & Engelhardt, G. (1998). Characterizing electrochemical systems in the frequency domain. Electrochimica Acta, 43(1-2), 87-107. doi:10.1016/s0013-4686(97)00238-7Schönleber, M., Klotz, D., & Ivers-Tiffée, E. (2014). A Method for Improving the Robustness of linear Kramers-Kronig Validity Tests. Electrochimica Acta, 131, 20-27. doi:10.1016/j.electacta.2014.01.034Garland, J. E., Pettit, C. M., & Roy, D. (2004). Analysis of experimental constraints and variables for time resolved detection of Fourier transform electrochemical impedance spectra. 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Electrochimica Acta, 42(12), 1781-1788. doi:10.1016/s0013-4686(96)00377-5Smulko, J., & Darowicki, K. (2003). Nonlinearity of electrochemical noise caused by pitting corrosion. Journal of Electroanalytical Chemistry, 545, 59-63. doi:10.1016/s0022-0728(03)00106-2Diard, J.-P., Le Gorrec, B., & Montella, C. (1994). Impedance measurement errors due to non-linearities—I. Low frequency impedance measurements. Electrochimica Acta, 39(4), 539-546. doi:10.1016/0013-4686(94)80098-7Diard, J.-P., Le Gorrec, B., & Montella, C. (1994). Theoretical formulation of the odd harmonic test criterion for EIS measurements. Journal of Electroanalytical Chemistry, 377(1-2), 61-73. doi:10.1016/0022-0728(94)03624-1Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Deviation from the polarization resistance due to non-linearity I - theoretical formulation. Journal of Electroanalytical Chemistry, 432(1-2), 27-39. doi:10.1016/s0022-0728(97)00213-1Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Deviation of the polarization resistance due to non-linearity II. Application to electrochemical reactions. Journal of Electroanalytical Chemistry, 432(1-2), 41-52. doi:10.1016/s0022-0728(97)00234-9Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Deviation of the polarization resistance due to non-linearity. III—Polarization resistance determination from non-linear impedance measurements. Journal of Electroanalytical Chemistry, 432(1-2), 53-62. doi:10.1016/s0022-0728(97)00233-7Diard, J.-P., Le Gorrec, B., & Montella, C. (1997). Non-linear impedance for a two-step electrode reaction with an intermediate adsorbed species. Electrochimica Acta, 42(7), 1053-1072. doi:10.1016/s0013-4686(96)00206-xVan Gheem, E., Pintelon, R., Vereecken, J., Schoukens, J., Hubin, A., Verboven, P., & Blajiev, O. (2004). Electrochemical impedance spectroscopy in the presence of non-linear distortions and non-stationary behaviour. 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Mechanistic equivalent circuit modelling of a commercial polymer electrolyte membrane fuel cell

[EN] Electrochemical impedance spectroscopy (EIS) has been widely used in the fuel cell field since it allows deconvolving the different physic-chemical processes that affect the fuel cell performance. Typically, EIS spectra are modelled using electric equivalent circuits. In this work, EIS spectra of an individual cell of a commercial PEM fuel cell stack were obtained experimentally. The goal was to obtain a mechanistic electric equivalent circuit in order to model the experimental EIS spectra. A mechanistic electric equivalent circuit is a semiempirical modelling technique which is based on obtaining an equivalent circuit that does not only correctly fit the experimental spectra, but which elements have a mechanistic physical meaning. In order to obtain the aforementioned electric equivalent circuit, 12 different models with defined physical meanings were proposed. These equivalent circuits were fitted to the obtained EIS spectra. A 2 step selection process was performed. In the first step, a group of 4 circuits were preselected out of the initial list of 12, based on general fitting indicators as the determination coefficient and the fitted parameter uncertainty. In the second step, one of the 4 preselected circuits was selected on account of the consistency of the fitted parameter values with the physical meaning of each parameter.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali + d grant (Ref: ACIF-2013-268).Giner-Sanz, JJ.; Ortega Navarro, EM.; Pérez-Herranz, V. (2018). Mechanistic equivalent circuit modelling of a commercial polymer electrolyte membrane fuel cell. Journal of Power Sources. 379:328-337. https://doi.org/10.1016/j.jpowsour.2018.01.066S32833737