C. Funfschilling

C. Funfschilling
SNCF · Mechanics and Dynamics

About

48
Publications
12,351
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
435
Citations

Publications

Publications (48)
Article
Full-text available
The speed profile of a train plays an important role in energy consumption and resulting costs. The industrial objective of this work is thus to develop a method to reduce the energy consumed by a train over a journey by playing on the driver commands (traction and braking forces) while respecting punctuality constraints. First, a rigid body approa...
Article
Full-text available
This paper presents a Bayesian calibration method for a simulation-based model with stochastic functional input and output. The originality of the method lies in an adaptation involving the representation of the likelihood function by a Gaussian process surrogate model, to cope with the high computational cost of the simulation, while avoiding the...
Preprint
Full-text available
This might be the first attempt than anyone has ever made to quantify the accuracy of the WHOLE ASSESSMENT PROCESS for railway vehicle running dynamics according to EN 14363 - not of the measurement accuracy of the instrumentation, but of Y/Q, SumY etc. It is based on the DynoTRAIN EU project's vast measurement campaign data in 4 EU countries. More...
Article
This paper presents a review of various works that highlight the importance of introducing the variability of the road-track/vehicle system into dynamic simulations as soon as this latter is meant to be predictive. The first section of the paper presents the Uncertainty Quantification, Verification and Validation method (UQ-VV). This latter propose...
Article
Full-text available
This paper presents a novel method for the state health monitoring of high-speed train suspensions from in-line acceleration measurements by embedded sensors, for maintenance purposes. We propose a model-based method relying on a multibody simulation code. It performs the simultaneous identification of several suspension mechanical parameters. It i...
Article
Full-text available
The objective of the work presented here is a bayesian calibration of parameters describing the mechanical characteristics of high-speed train suspensions for maintenance purposes. This calibration is achieved by comparing simulation results to on-track acceleration measurements. It requires the estimation on the multidimensionnal admissible set of...
Conference Paper
Full-text available
The objective of the work presented here is a bayesian calibration of parameters describing the mechanical characteristics of high-speed train suspensions for maintenance purposes. This calibration is achieved by comparing simulation results to on-track accelerometric measurements. It requires the estimation on the multidimensionnal admissible set...
Conference Paper
Full-text available
The objective of the work presented here is the inverse identification of parameters describing the mechanical characteristics of high-speed train suspensions for maintenance purposes. This identification is achieved by comparing simulation results to on-track accelerometric measurements. It requires the introduction of an output predictive error a...
Article
The European FP7 project DynoTRAIN was set up in order to close important open points in the technical specifications for interoperability of the trans-European rail system and to contribute to European standards. This contribution targeted the reduction of cost of the process for the assessment of running dynamics characteristics that is required...
Article
For the calibration of multi-body models of railway vehicles, the identification of the model parameters from on-track measurement is required. This involves the solution of an inverse problem by minimising the misfit function which describes the distance between model and measurement using optimisation methods. The application of gradient-based op...
Article
Full-text available
There is a great interest to predict the long- term evolution of the track irregularities for a given track stretch of the high-speed train network, in order to be able to anticipate the start off of the maintenance operations. In this paper, a stochastic predictive model, based on big data made up of a lot of experimental measurements performed on...
Article
Full-text available
The influence of the track geometry on the dynamic response of the train is of great concern for the railway companies, because they have to guarantee the safety of the train passengers in ensuring the stability of the train. In this paper, the long-term evolution of the dynamic response of the train on a stretch of the railway track is studied wit...
Article
The present dynamic certification process that is based on experiments has been essentially built on the basis of experience. The introduction of simulation techniques into this process would be of great interest. However, an accurate simulation of complex, nonlinear systems is a difficult task, in particular when rare events (for example, unstable...
Article
This paper describes the work performed in Work Package 6 of the European project DynoTRAIN. Its task was to investigate the effects that uncertainties present within the track and running conditions have on the simulated behaviour of a railway vehicle. Methodologies and frameworks for using virtual simulation and statistical tools, in order to red...
Conference Paper
Full-text available
The paper deals with the statistical inverse problem for the identification of a non- Gaussian tensor-valued random field in high stochastic dimension. Such a random field can represent the parameter of a boundary value problem (BVP). The available experimental data, which correspond to observations, can be partial and limited. A general methodolog...
Article
Full-text available
At its building, the theoretical new railway line is supposed to be made of perfect straight lines and curves. This track geometry is however gradually damaged and regularly subjected to maintenance operations. The analysis of these track irregularities is a key issue as the dynamic behaviour of the trains is mainly induced by the track geometry. I...
Article
French high speed line network is in its majority composed of ballasted track. Nonethe- less in 2007, a new experimental slab track was constructed in the new East European High speed line, from Paris to Strasbourg, operating at 320 km/h. Special transition zones were then designed and constructed in order to provide the correct stiffness tran- sit...
Article
Full-text available
The use of reduced basis has spread to many scientific fields for the past 50 years to condense the statistical properties of stochastic processes. Among these bases, the classical Karhunen –Lòeve basis corresponds to the Hilbertian basis that is constructed as the eigenfunctions of the covariance operator of the stochastic process of interest. The...
Article
Full-text available
This paper aims at estimating the vehicle suspension parameters of a TGV (Train à Grande Vitesse) train from measurement data. A better knowledge of these parameters is required for virtual certification or condition monitoring applications. The estimation of the parameter values is performed by minimising a misfit function describing the distance...
Conference Paper
The European railway system has been ensuring high safety levels compared with other transport modes for many years. Research is thus focused on reducing costs while at least maintaining, and possibly improving, safety. One important driver in this sense is the cost for authorisation of vehicles to enter service. Three research projects, collective...
Article
Full-text available
High speed trains are currently meant to run faster and to carry heavier loads, while being less energy consuming and still respecting the security and comfort certification criteria. To face these challenges, a better understanding of the interaction between the dynamic train behavior and the track geometry is needed. As during its lifecycle, the...
Conference Paper
Full-text available
The study presented here aims at characterizing the influence of the rail wear on the train dynamic response. Rail profiles have been measured on a real track and post-processed in order to be used in a mutlibody simulation of the train's response. Wear modes have been extracted from the measures with a Principal Orthogonal Decomposition (POD). The...
Article
Full-text available
Due to scaling effects, when dealing with vector-valued random fields, the classical Karhunen–Loève expansion, which is optimal with respect to the total mean square error, tends to favorize the components of the random field that have the highest signal energy. When these random fields are to be used in mechanical systems, this phenomenon can intr...
Article
This presentation deals with an innovative approach to analyze complex and nonlinear systems, which are excited by non-Gaussian and non-stationary random fields, by solving of a statistical inverse problem with experimental measurements. The methodology proposed is applied to the case of a railway system: a train is a nonlinear system with many deg...
Article
Full-text available
This paper deals with the identification in high dimensions of a polynomial chaos expansion of random vectors from a set of realizations. Due to numerical and memory constraints, the usual polynomial chaos identification methods are based on a series of truncations that induce a numerical bias. This bias becomes very detrimental to the convergence...
Article
Railway dynamic simulations are increasingly used to predict and analyse the behaviour of the vehicle and of the track during their whole life cycle. Up to now however, no simulation has been used in the certification procedure even if the expected benefits are important: cheaper and shorter procedures, more objectivity, better knowledge of the beh...
Article
A multiscale analysis of the mechanical behavior of bovine Haversian cortical bone is presented in the frame-work of linear elasticity. Cortical bone displays a complex microstructure that includes four phases: Haversian canals, osteons, cement lines, and interstitial bone. Based on close experimental observations, a Monte Carlo algorithm is implem...
Conference Paper
Full-text available
This paper presents a methodology to build representative railway track geometries thanks to a stochastic modelling. This modelling, which has to integrate the statistical and spatial variabilities and dependencies, is a key issue when using simulation for conception, maintenance or certification purposes, as the dynamic behaviour of the trains is...
Conference Paper
The main objective of the study presented here is to evaluate the rolling contact fatigue of the rail for different running conditions. The modeling strategy couples multibody simulations and finite element modelling; the loading applied by the wheel on the rail is evaluated thanks to a railway dynamic simulation. The asymptotic stresses of the rai...
Article
Full-text available
The shear strength properties of a thin three-dimensional railway ballast layer were studied by mean of numerical vertical compression tests. Fresh and recycled ballast digitized grains were used. Vertical strength comes from the increase of face-face contacts, which are more important in fresh ballast. Shape and force anisotropies are equally impo...
Article
In this work first results from an ongoing work on parameter identification for a TGV model are presented. The first step of the study is the modeling of the vehicle with a multi-body system code and the comparison of the simulation results with measurements in the time domain. The suspension characteristics are difficult to determine since they ca...
Article
The main objective of this study is to compare different contact models by the simulation of a derailment case test. The softwares are Vampire, and Vocolin, which can handle a non Hertzian contact, named STRIPES. The study shows that the experimental measurements are globally well predicted by the simulations and similar between codes. Vocolin pred...

Network

Cited By

Projects

Project (1)