Acoustic metamaterial plates for elastic wave absorption and structural vibration suppression

A 3D absolute nodal coordinate finite element model to compute the initial configuration of a railway catenary

The ambient temperature effect may result in limitations of vibration-based SHM approaches for civil engineering structures. This paper addresses the issue of discriminating changes in modal parame...

https://hal.inria.fr/inria-00164852/document

Merging Sensor Data from Multiple Temperature Scenarios for Vibration Monitoring of Civil Structures

This paper aims to provide an overview of the present status of research in pantograph–overhead line interaction and to outline future research challenges. A review of currently used modelling and ...

Pantograph–catenary interaction: recent achievements and future research challenges

The standard approach to railway vehicle dynamic analysis includes running the vehicle multibody models in rigid railway tracks. The wheel–rail contact, independently of the rolling contact model used, is either handled online or via lookup tables. This traditional approach disregards the coupling effects between the railway vehicle dynamics and the railway track flexibility. In this work the assumption of rigidity of the railway track is relaxed and a finite element model of the complete track, i.e. rails, pads, sleepers, ballast and infrastructure, is used to represent the track geometry and flexibility. A rail–wheel contact model that evaluates the contact conditions and forces is used online. The dynamics of the railway vehicle is described using a multibody methodology while the track structure is described using a finite element approach. Due to the fact that not only the multibody and the finite element dynamic analysis use different integration algorithms but also because the vehicle and track models are simulated in different, codes a co-simulation procedure is proposed and demonstrated to address the coupled dynamics of the system. This approach allows us to analyze the vehicle dynamics in a flexible track with a general geometry modeled with finite elements, i.e. including curvature, cant, vertical slopes and irregularities, which is another novel contribution. The methodology proposed in this work is demonstrated in an application, in which the railway vehicle–track interaction shows the influence of the vehicle dynamics on the track dynamics and vice versa.

/pdf/a-co-simulation-approach-to-the-wheel-rail-contact-with-32ctr050g3.pdf

A co-simulation approach to the wheel–rail contact with flexible railway track

This paper presents recent developments undertaken by SNCF Innovation & Research Department on numerical modelling of pantograph catenary interaction. It aims at describing an efficient co-simulation process between finite element (FE) and multibody (MB) modelling methods. FE catenary models are coupled with a full flexible MB representation with pneumatic actuation of pantograph. These advanced functionalities allow new kind of numerical analyses such as dynamic improvements based on innovative pneumatic suspensions or assessment of crash risks crossing areas that demonstrate the powerful capabilities of this computing approach.

/pdf/pantograph-catenary-dynamic-optimisation-based-on-advanced-1ebt8872y2.pdf

Pantograph catenary dynamic optimisation based on advanced multibody and finite element co-simulation tools

Experimentally, modal damping is known to allow a relatively accurate representation of damping for wide frequency ranges. For transient simulation of full finite element models, viscous damping is very often the only formulation that is associated with an acceptable computation time. In the absence of a proper material damping model, it is common to assume Rayleigh damping, where the viscous matrix is a linear combination of the mass and stiffness, or piece-wise Rayleigh damping. This representation very often results in modal damping ratios that do not correspond to the physical reality that can be tested. One thus introduces an implicit representation of the viscous matrix that allows transient time simulation with minor time penalty, while using a much more appropriate damping representation. Modal amplitudes are also considered to postprocess time simulations and analyze damping levels. When studying vibrations induced by the passage of pantographs under a catenary, the high modal density of catenaries and the load moving over a large part of the model is a strong motivation to use full model transient analysis. Modal damping is shown to be a practical tool to analyze the properties of this complex system.

https://hal.archives-ouvertes.fr/hal-00589953/document

Using modal damping for full model transient analysis. Application to pantograph/catenary vibration

Classically Component Mode Synthesis has been used to couple models from different sources (mixed test and analysis, different companies, different software, ...) or reduce models. The focus of this paper is on using component modes in a design cycle. Component modes are the natural representation in the lowest part design cycle. In NVH applications, it is well known that coupling at the system level makes understanding of the impact of component design changes difficult. The paper details and uses the disjoint component synthesis method. Like classical CMS this synthesis method considers reduced component models and couples these models to obtain a system level synthesis. The first novel aspect is that a physical interface is assumed to exist between components. Synthesis thus becomes a trivial application of model assembly. The second novel aspect is that components are reduced using component modes and the trace of nominal system modes, thus allowing exact predictions for the nominal design. Illustrations of the methodology are given for an automotive brake application.

/pdf/using-component-modes-in-a-system-design-process-2ak04w250j.pdf

Using component modes in a system design process

OSCAR (Outil de Simulation du CAptage pour la Reconnaissance des defauts) is the pantograph–catenary dynamic software developed by Societe Nationale des Chemins de fer Francais (SNCF) since 2004. A three-dimensional finite element (FE) mesh allows the modelling of any catenary type: alternating current (AC) or direct current (DC) designs, and conventional or high-speed lines. It is a representative of the real overhead line geometry, with contact wire (CW) irregularities, staggered alignment of the CW, dropper spacing, wire tension, etc. Nonlinearities, such as slackening of droppers and unilateral contact between the pantograph and the CW, are taken into account. Several pantograph models can be used, with a complexity level growing from the three-lumped-mass model to the multibody model. In the second case, a cosimulation between the FE method catenary and the multibody pantograph models has been developed. Industrial features for pre- and post-treatments were developed to increase robustness of results...

/pdf/oscar-statement-of-methods-fx76270u6v.pdf

OSCAR statement of methods

OpenFEM est une boite a outils elements finis, developpee par SDTools et l'INRIA, dans l'environnement de calculs matriciels MATLAB. Cette librairie, distribuee avec une licence libre de type LGPL, fournit des outils de generations de modeles, d'elements multi-physiques, de pre- et post-traitement. La Structural Dynamics Toolbox est un produit commercial sous MATLAB qui integre OpenFEM comme moteur de calcul element fini.

https://hal.archives-ouvertes.fr/hal-01422253/document

Jean-Philippe Bianchi

Papers

Pantograph catenary dynamic optimisation based on advanced multibody and finite element co-simulation tools

Using modal damping for full model transient analysis. Application to pantograph/catenary vibration

Using component modes in a system design process

OSCAR statement of methods

Structural Dynamics Toolbox et OpenFEM