https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 13 Jul 2026 06:26:02 GMT 2026-07-13T06:26:02Z http://hdl.handle.net/10985/10854 Wave damping and evanescence: how to combine the spatial and temporal visions of the same problem? 1 BALMES, Etienne; RÉBILLAT, Marc; ARLAUD, Elodie It is proposed to analyze the forced response of periodic structures using a 2D Fourier transform using continuous time and discrete space. The simple example of compression waves is used to show that this response can be used to define poles in the wavenumber domain corresponding to evanescent waves or poles in the frequency domain corresponding to damped periodic modes. Link with classical computational methods based on FEM models of cells was done for both the periodic solution and wave based approach (SAFE, WFE). Two examples are analyzed in more detail: a simple train track model exhibiting a band-gap and the more complex case of a honeycomb panel where cell wall bending occurs within the band of interest. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/10854 2016-01-01T00:00:00Z BALMES, Etienne RÉBILLAT, Marc ARLAUD, Elodie It is proposed to analyze the forced response of periodic structures using a 2D Fourier transform using continuous time and discrete space. The simple example of compression waves is used to show that this response can be used to define poles in the wavenumber domain corresponding to evanescent waves or poles in the frequency domain corresponding to damped periodic modes. Link with classical computational methods based on FEM models of cells was done for both the periodic solution and wave based approach (SAFE, WFE). Two examples are analyzed in more detail: a simple train track model exhibiting a band-gap and the more complex case of a honeycomb panel where cell wall bending occurs within the band of interest. http://hdl.handle.net/10985/11295 A reduced track model to understand the dynamic behavior of the track ARLAUD, Elodie; COSTA D'AGUIAR, Sofia; BALMES, Etienne Nowadays, trends in railways are for more traffic at higher speed, whereas infrastructures remain basically unchanged. As track design has evolved over the years based on experience, the introduction of numerical models could be a tool to gain better understanding of track behaviour and improve track design. Dynavoie software is a finite element model which aims to offer a comprehensive view of the track, taking into account all the components of the system, from the rail to the soil. This global approach is a specificity of the software, as well as the low computation time due to the reduction strategy. This paper presents model validation steps in the frequency domain, computing a receptance test and comparing it to another model presented in the literature. A characterisation of the railway substructure based on this test is then proposed. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/11295 2014-01-01T00:00:00Z ARLAUD, Elodie COSTA D'AGUIAR, Sofia BALMES, Etienne Nowadays, trends in railways are for more traffic at higher speed, whereas infrastructures remain basically unchanged. As track design has evolved over the years based on experience, the introduction of numerical models could be a tool to gain better understanding of track behaviour and improve track design. Dynavoie software is a finite element model which aims to offer a comprehensive view of the track, taking into account all the components of the system, from the rail to the soil. This global approach is a specificity of the software, as well as the low computation time due to the reduction strategy. This paper presents model validation steps in the frequency domain, computing a receptance test and comparing it to another model presented in the literature. A characterisation of the railway substructure based on this test is then proposed. http://hdl.handle.net/10985/18597 Receptance of railway tracks at low frequency: Numerical and experimental approaches ARLAUD, Elodie; COSTA D'AGUIAR, Sofia; BALMES, Etienne This paper presents numerical simulations and experimental studies on the frequency domain behavior of railway track below 100 Hz, focusing on the link between the substructure properties of the track and its global dynamic response. A numerical method in the frequency domain is first proposed and used to understand the frequency response of a railway track with a French High Speed Line (HSL) design. Then, low-frequency receptance measurements, performed in a specific HSL test site with different designs, are presented. These experimental results are used to characterize a change in the track substructure. Further analysis of the full track responses associated with peaks visible in the receptance test is conducted using numerical simulations. In the considered test case, these simulations demonstrate the existence of the superstructure and ballast resonance on relatively soft mats. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/18597 2016-01-01T00:00:00Z ARLAUD, Elodie COSTA D'AGUIAR, Sofia BALMES, Etienne This paper presents numerical simulations and experimental studies on the frequency domain behavior of railway track below 100 Hz, focusing on the link between the substructure properties of the track and its global dynamic response. A numerical method in the frequency domain is first proposed and used to understand the frequency response of a railway track with a French High Speed Line (HSL) design. Then, low-frequency receptance measurements, performed in a specific HSL test site with different designs, are presented. These experimental results are used to characterize a change in the track substructure. Further analysis of the full track responses associated with peaks visible in the receptance test is conducted using numerical simulations. In the considered test case, these simulations demonstrate the existence of the superstructure and ballast resonance on relatively soft mats. http://hdl.handle.net/10985/18600 A general superelement generation strategy for piecewise periodic media PINAULT, Hadrien; ARLAUD, Elodie; BALMES, Etienne Structures composed of repetitions of multiple identical cells are common and have been the object of a large body of literature on waveguides, periodic media, and cyclic symmetry. Starting from a cell model, possibly with a large number of Degrees of Freedom both inside the cell and on its edges, the objective of this paper is to propose a Ritz-Galerkin reduction procedure retaining the standard second order model form and periodicity properties of the original model, while controlling accuracy in terms of model bandwidth and reproduction of the forced response to applied loads. The procedure is classically decomposed in two phases: subspace learning and basis generation. For the learning phase, Wave Finite Element (WFE) and periodic computations are presented as alternatives. The latter are then preferred for their easier control on the reduced model accuracy using classical modal synthesis and the simple choice of few target wavelengths. For the basis generation phase, constraints needed to generate a periodic superelement are defined and numerical procedures to generate a basis verifying those constraints are proposed. The validity of the reduction is demonstrated for the case of a cell with random elastic properties presenting bandgaps, local modes and wavemode crossing. Accurate predictions of modes and damped forced response are given for both the infinite and finite cases, using frequency and time simulations. The proposed analysis illustrates tracking of waveshapes, evaluation of significant waves by computation of the forced response in the frequency/wavenumber domain and interpretation of the relation between the infinite and finite forced responses. The case of a railway track with edges and transitions between multiple periodic zones is finally used to illustrate scalability issues. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18600 2020-01-01T00:00:00Z PINAULT, Hadrien ARLAUD, Elodie BALMES, Etienne Structures composed of repetitions of multiple identical cells are common and have been the object of a large body of literature on waveguides, periodic media, and cyclic symmetry. Starting from a cell model, possibly with a large number of Degrees of Freedom both inside the cell and on its edges, the objective of this paper is to propose a Ritz-Galerkin reduction procedure retaining the standard second order model form and periodicity properties of the original model, while controlling accuracy in terms of model bandwidth and reproduction of the forced response to applied loads. The procedure is classically decomposed in two phases: subspace learning and basis generation. For the learning phase, Wave Finite Element (WFE) and periodic computations are presented as alternatives. The latter are then preferred for their easier control on the reduced model accuracy using classical modal synthesis and the simple choice of few target wavelengths. For the basis generation phase, constraints needed to generate a periodic superelement are defined and numerical procedures to generate a basis verifying those constraints are proposed. The validity of the reduction is demonstrated for the case of a cell with random elastic properties presenting bandgaps, local modes and wavemode crossing. Accurate predictions of modes and damped forced response are given for both the infinite and finite cases, using frequency and time simulations. The proposed analysis illustrates tracking of waveshapes, evaluation of significant waves by computation of the forced response in the frequency/wavenumber domain and interpretation of the relation between the infinite and finite forced responses. The case of a railway track with edges and transitions between multiple periodic zones is finally used to illustrate scalability issues. http://hdl.handle.net/10985/10976 Numerical Study of Railway Track Dynamics : Case of a Transition Zone ARLAUD, Elodie; COSTA D'AGUIAR, Sofia; BALMES, Etienne; FAUSSURIER, Guillaume The main objective of this paper is to present an innovative numerical tool to represent the track and platform dynamic behavior under passing trains. Dynavoie is currently being developed for engineering purposes at SNCF. It is specifically designed to correctly reproduce the track and platform dynamic behaviors in the time domain. This model is based on the Finite Element Method (FEM), adapted to the railway track using model reduction techniques. Taking advantage of the periodicity of the track introduced by the regular sleeper spacing, one or several basic slices containing all the geometric properties of the structure can be identified. Static and periodic responses of these slices are computed. Then, reduction is performed using these deformations.Thus the number of degrees of freedom of the model is highly reduced. This reduction induces a decrease in computation time with limited accuracy loss in the representation of track dynamics. The methodology will be further described in this paper. The second novelty of this work is to use this model to analyze the dynamic behavior of a transition zone located in a French high speed line. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/10976 2016-01-01T00:00:00Z ARLAUD, Elodie COSTA D'AGUIAR, Sofia BALMES, Etienne FAUSSURIER, Guillaume The main objective of this paper is to present an innovative numerical tool to represent the track and platform dynamic behavior under passing trains. Dynavoie is currently being developed for engineering purposes at SNCF. It is specifically designed to correctly reproduce the track and platform dynamic behaviors in the time domain. This model is based on the Finite Element Method (FEM), adapted to the railway track using model reduction techniques. Taking advantage of the periodicity of the track introduced by the regular sleeper spacing, one or several basic slices containing all the geometric properties of the structure can be identified. Static and periodic responses of these slices are computed. Then, reduction is performed using these deformations.Thus the number of degrees of freedom of the model is highly reduced. This reduction induces a decrease in computation time with limited accuracy loss in the representation of track dynamics. The methodology will be further described in this paper. The second novelty of this work is to use this model to analyze the dynamic behavior of a transition zone located in a French high speed line. http://hdl.handle.net/10985/10916 Validation of a reduced model of railway track allowing long 3D dynamic calculation of train-track interaction ARLAUD, Elodie; COSTA D'AGUIAR, Sofia; BALMES, Etienne In order to face challenges of increased traffic and speed on their infrastructures, railway companies need to develop numerical tools able to predict the dynamic behaviour of the track. Currently, two approaches are widely used: the first one is a train-based methodology in which train dynamic is well reproduced but track is only represented as equivalent springs, the second one is a FEM model or FEM/BEM model of track in which the train is simply modeled as a moving load but the complexity of track taken into account. Dynavoie software studied in this work aims to offer a new approach by representing in details both track and train. Understanding train-track interaction requires transients on long track segments, leading to very large finite element models and high computation time. The specificity of Dynavoie software is to use periodic properties of the track to generate a reduced slice model, and then build the track as a combination of these slices. Computation time is then highly reduced. The present work focuses on the initial step of the model reduction where computations in the frequency and wave domains are used. The resulting 3D periodic computations are compared to 2.5D FEM/BEM results from the literature and the content of the receptance curve is discussed in relation with dispersion curves. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/10916 2014-01-01T00:00:00Z ARLAUD, Elodie COSTA D'AGUIAR, Sofia BALMES, Etienne In order to face challenges of increased traffic and speed on their infrastructures, railway companies need to develop numerical tools able to predict the dynamic behaviour of the track. Currently, two approaches are widely used: the first one is a train-based methodology in which train dynamic is well reproduced but track is only represented as equivalent springs, the second one is a FEM model or FEM/BEM model of track in which the train is simply modeled as a moving load but the complexity of track taken into account. Dynavoie software studied in this work aims to offer a new approach by representing in details both track and train. Understanding train-track interaction requires transients on long track segments, leading to very large finite element models and high computation time. The specificity of Dynavoie software is to use periodic properties of the track to generate a reduced slice model, and then build the track as a combination of these slices. Computation time is then highly reduced. The present work focuses on the initial step of the model reduction where computations in the frequency and wave domains are used. The resulting 3D periodic computations are compared to 2.5D FEM/BEM results from the literature and the content of the receptance curve is discussed in relation with dispersion curves.