https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 15 May 2026 01:50:02 GMT 2026-05-15T01:50:02Z http://hdl.handle.net/10985/8236 Introduction of variability in pantograph-catenary dynamic simulations VO VAN, Olivier; MASSAT, Jean-Pierre; LAURENT, Christophe; BALMES, Etienne Currently, pantograph-catenary dynamic simulations codes are mainly based on deterministic approaches. However, the contact force between catenary and pantograph depends on many key parameters that are not always quantified precisely. To get a better chance of addressing extreme or combinations of critical conditions, methodologies to consider variability are thus necessary. Aerodynamic forces and geometrical irregularities of catenaries are thought to be significant sources of variability in measurement and this paper proposes methods to take them into account. Results are compared with measurements to see the importance of the considered parameters with respect to global variability observed in measurements. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/8236 2013-01-01T00:00:00Z VO VAN, Olivier MASSAT, Jean-Pierre LAURENT, Christophe BALMES, Etienne Currently, pantograph-catenary dynamic simulations codes are mainly based on deterministic approaches. However, the contact force between catenary and pantograph depends on many key parameters that are not always quantified precisely. To get a better chance of addressing extreme or combinations of critical conditions, methodologies to consider variability are thus necessary. Aerodynamic forces and geometrical irregularities of catenaries are thought to be significant sources of variability in measurement and this paper proposes methods to take them into account. Results are compared with measurements to see the importance of the considered parameters with respect to global variability observed in measurements. http://hdl.handle.net/10985/9224 Introduction of variability into pantograph–catenary dynamic simulations VO VAN, Olivier; MASSAT, Jean-Pierre; LAURENT, Christophe; BALMES, Etienne Currently, pantograph-catenary dynamic simulations are mainly based on deterministic approaches. However, the contact force between catenary and pantograph depends on many key parameters that are not always quantified precisely and can vary in time and space. To get a better chance of addressing extreme or combined critical conditions, methodologies to consider variability are thus necessary. Aerodynamic forces and geometrical irregularities of catenaries are thought to be significant sources of variability in measurement and this paper proposes methods to take them into account. Results are compared with measurements to correlate the effect of the considered parameters with experimentally observed variability. Finally, a virtual certification example is shown, with a study of the influence of speed on the impact of variability. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/9224 2014-01-01T00:00:00Z VO VAN, Olivier MASSAT, Jean-Pierre LAURENT, Christophe BALMES, Etienne Currently, pantograph-catenary dynamic simulations are mainly based on deterministic approaches. However, the contact force between catenary and pantograph depends on many key parameters that are not always quantified precisely and can vary in time and space. To get a better chance of addressing extreme or combined critical conditions, methodologies to consider variability are thus necessary. Aerodynamic forces and geometrical irregularities of catenaries are thought to be significant sources of variability in measurement and this paper proposes methods to take them into account. Results are compared with measurements to correlate the effect of the considered parameters with experimentally observed variability. Finally, a virtual certification example is shown, with a study of the influence of speed on the impact of variability. http://hdl.handle.net/10985/11802 Waves, modes and properties with a major impact on dynamic pantograph-catenary interaction VO VAN, Olivier; MASSAT, Jean-Pierre; BALMES, Etienne Understanding the dynamic behavior of the pantograph-catenary system is crucial for design improvement, but many factors inuence the contact force, which is the main design objective. To give a proper un-derstanding of dynamic characteristics, the paper uses a combination of mass drop tests on a catenary, analytic models and parametric _nite element model simulations allowing a ne analysis of the inuence of train speed. The _rst contributor to contact force variations is the geometry of the catenary under gravity loading. This parameter is however shown to be insu_cient to explain higher frequency e_ects. The second contributor is the propagation of waves in the contact and messenger wires. The inuence of wave dis-persion is _rst demonstrated, which emphasizes the importance of considering the bending sti_ness. Wave compensation by droppers and reections at the mast are then shown to be important. Characteristic times associated with wave group velocities are _nally used to explain the series of harmonic contributions visible in spectra in the catenary and pantograph frames. Finally, modes are shown to play a role particularly when their frequencies coincide with other contributions. The notion of mode groups, associated wave velocities and relevant design variables are discussed. Several observations pave the way for future work on catenary design. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/11802 2017-01-01T00:00:00Z VO VAN, Olivier MASSAT, Jean-Pierre BALMES, Etienne Understanding the dynamic behavior of the pantograph-catenary system is crucial for design improvement, but many factors inuence the contact force, which is the main design objective. To give a proper un-derstanding of dynamic characteristics, the paper uses a combination of mass drop tests on a catenary, analytic models and parametric _nite element model simulations allowing a ne analysis of the inuence of train speed. The _rst contributor to contact force variations is the geometry of the catenary under gravity loading. This parameter is however shown to be insu_cient to explain higher frequency e_ects. The second contributor is the propagation of waves in the contact and messenger wires. The inuence of wave dis-persion is _rst demonstrated, which emphasizes the importance of considering the bending sti_ness. Wave compensation by droppers and reections at the mast are then shown to be important. Characteristic times associated with wave group velocities are _nally used to explain the series of harmonic contributions visible in spectra in the catenary and pantograph frames. Finally, modes are shown to play a role particularly when their frequencies coincide with other contributions. The notion of mode groups, associated wave velocities and relevant design variables are discussed. Several observations pave the way for future work on catenary design. http://hdl.handle.net/10985/26071 Non-linear viscoelastic damping: designing tests needed for transient simulation of a rail track ETIENNE, BALMES; MARTIN, Guillaume; VO VAN, Olivier Viscoelastic materials are widely used in many industries for their ability to undergo large deformation and dissipate energy. Pads placed between rail and sleeper experience large deformation when the train passes. This is important for load distribution to the sleepers. They also strongly contribute to vibration damping, and thus to lowering noise emissions associated with rail/wheel contact. There is thus a need to have a model that allows transient simulation in a regime accounting for dependence of the behavior on time history including multiple time scales. The study revisits the design and exploitation of test sequences combining steps, ramps, stepped sine and sweeps in frequency and amplitude. Illustrations are given for full scale tests of rail-spleeper pads. Sun, 01 Sep 2024 00:00:00 GMT http://hdl.handle.net/10985/26071 2024-09-01T00:00:00Z ETIENNE, BALMES MARTIN, Guillaume VO VAN, Olivier Viscoelastic materials are widely used in many industries for their ability to undergo large deformation and dissipate energy. Pads placed between rail and sleeper experience large deformation when the train passes. This is important for load distribution to the sleepers. They also strongly contribute to vibration damping, and thus to lowering noise emissions associated with rail/wheel contact. There is thus a need to have a model that allows transient simulation in a regime accounting for dependence of the behavior on time history including multiple time scales. The study revisits the design and exploitation of test sequences combining steps, ramps, stepped sine and sweeps in frequency and amplitude. Illustrations are given for full scale tests of rail-spleeper pads. http://hdl.handle.net/10985/10975 Sensitivity analysis of catenary geometry on current collection quality VO VAN, Olivier; BALMES, Etienne; CAPITAINE, Arnaud; LORANG, Xavier A global sensitivity analysis is led on catenary parameters such as dropper lengths, height of the messenger wire at masts and mechanical tensions in the wires thanks to the Sobol indices. All parameters are defined using experimental measurements. A set of geometric and dynamic criteria is selected as output and the contribution of theinput parameters to the output variability is quantified. It is shown that the dynamicinteraction is mainly sensitive to the mechanical tensions in contact and messenger wires whereas existing geometric criteria are mainly dependent on height of messenger wire at masts. Moreover, selected geometric criteria available using geometry measurements are hardly correlated with dynamic criteria. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/10975 2016-01-01T00:00:00Z VO VAN, Olivier BALMES, Etienne CAPITAINE, Arnaud LORANG, Xavier A global sensitivity analysis is led on catenary parameters such as dropper lengths, height of the messenger wire at masts and mechanical tensions in the wires thanks to the Sobol indices. All parameters are defined using experimental measurements. A set of geometric and dynamic criteria is selected as output and the contribution of theinput parameters to the output variability is quantified. It is shown that the dynamicinteraction is mainly sensitive to the mechanical tensions in contact and messenger wires whereas existing geometric criteria are mainly dependent on height of messenger wire at masts. Moreover, selected geometric criteria available using geometry measurements are hardly correlated with dynamic criteria. http://hdl.handle.net/10985/8596 Statistical identification of geometric parameters for high speed train catenary VO VAN, Olivier; BALMES, Etienne; MASSAT, Jean-Pierre Pantograph/catenary interaction is known to be strongly dependent on the static geometry of the catenary, this research thus seeks to build a statistical model of this geometry. Sensitivity analyses provide a selection of relevant parameters affecting the geometry. After correction for the dynamic nature of the measurement, provide a database of measurements. One then seeks to solve the statistical inverse problem using the maximum entropy principle and the maximum likelihood method. Two methods of multivariate density estimations are presented, the Gaussian kernel density estimation method and the Gaussian parametric method. The results provide statistical information on the significant parameters and show that the messenger wire tension of the catenary hides sources of variability that are not yet taken into account in the model. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8596 2014-01-01T00:00:00Z VO VAN, Olivier BALMES, Etienne MASSAT, Jean-Pierre Pantograph/catenary interaction is known to be strongly dependent on the static geometry of the catenary, this research thus seeks to build a statistical model of this geometry. Sensitivity analyses provide a selection of relevant parameters affecting the geometry. After correction for the dynamic nature of the measurement, provide a database of measurements. One then seeks to solve the statistical inverse problem using the maximum entropy principle and the maximum likelihood method. Two methods of multivariate density estimations are presented, the Gaussian kernel density estimation method and the Gaussian parametric method. The results provide statistical information on the significant parameters and show that the messenger wire tension of the catenary hides sources of variability that are not yet taken into account in the model. http://hdl.handle.net/10985/10918 Damping characterization of a high speed train catenary VO VAN, Olivier; BALMES, Etienne; LORANG, Xavier Catenary damping has long been a tuning parameter in pantograph-catenary dynamic interaction models. As the computed contact force is highly sensitive to the choice of damping model or coefficients, it became critical to measure it independently of the pantograph. Original tests have been conducted on a real catenary and damping identification shows a very low level of damping for a large frequency range. A fitted Rayleigh model and a combined modal and Rayleigh model are proposed and compared with a reference damping model found in literature as well as with the tests. Finally, the consequences on a typical contact force simulation are analysed and the most relevant model is chosen. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/10918 2015-01-01T00:00:00Z VO VAN, Olivier BALMES, Etienne LORANG, Xavier Catenary damping has long been a tuning parameter in pantograph-catenary dynamic interaction models. As the computed contact force is highly sensitive to the choice of damping model or coefficients, it became critical to measure it independently of the pantograph. Original tests have been conducted on a real catenary and damping identification shows a very low level of damping for a large frequency range. A fitted Rayleigh model and a combined modal and Rayleigh model are proposed and compared with a reference damping model found in literature as well as with the tests. Finally, the consequences on a typical contact force simulation are analysed and the most relevant model is chosen.