Post-Doctorants


Offre de post-doctorat : Modeling and simulation of cable transport systems : INRIA and STRMTG, Grenoble, France.
Starting date between November 2017 up to January 2018 (30/10/2017)

Keywords:
cable transport system, nonlinear dynamics, contact, friction, impacts, flexible multi-body systems, modeling and simulation, software development.

Context:
The recent development of cable transport systems, especially in view of urban applications requires new research to better qualify their mechanical behaviors to improve their safety and performance. The study of the dynamics of cable in interaction with their supports (towers or pylons) by means of sheaves (pulley assemblies) is of utmost importance for the understanding of the global mechanical response of ropeways. Most of the practical study of such systems are generally based on strong assumptions: a) in a first approach, the dimensioning is made under static assumptions, neglecting the dynamics of the cable and b) the support are also considered to be perfect boundary conditions (clamped or bilateral frictionless prismatic joint). The goal of this long-term collaboration between STRMTG and INRIA is to improve the numerical simulation of cable transport systems into two di-rections. Firstly, the dynamics of the cable together with suspended moving pendulums that model the vehicles will taken into account. Secondly, a more accurate modeling of support including unilateral contact conditions, impacts and Coulomb’s friction will be developed. The main objective is to model the dynamics of the cable (oscillations of the line and the vehicles) and to understand the influence of the passage of a vehicle over a tower, by modeling contact and friction in sheaves. The final goal is to develop a numerical model and software code by extending the ability of Siconos, in order to simulate cable transport systems with various levels of accuracy in the modeling.

Objectives:
After a careful study of the literature, the objectives of the post-doc will be:
− to develop a numerical model of the dynamics a translating cable with moving suspended pen-dulums over two simple supports. In this step, the dynamics of terms of waves propagation (existence and stability) will be studied in details.
− to extend the previous step towards multiple supports that takes into account unilateral contact, impact and friction. The influence of the frictional contact boundary conditions will be studied in terms of tension in the rope and amplitude of the oscillations.
− to develop a model of sheaves with fixed pulleys and a moving cable with contact and friction and to study the passage of the grip of the vehicle into the sheaves. The effect of the nonsmooth behavior generated by the contact conditions over the dynamics of the cable will be detailed.
− to improve the model of sheaves by considering the rigid multi-body system that links the pul-leys.

Skills:
The candidate must have a strong background in computational mechanics and nonlinear
dynamics. Furthermore, the candidate must show some abilities to develop scientific computing code
in a standard language (python, C, C++).

Environment:
This post-doc will be supervised by Vincent Acary (INRIA) and M. Weiss (STRMTG). Inria is the French National Institute for computer science and applied mathematics that promotes “scientific excellence for technology transfer and society”. The post-doc candidate will be welcome in the Bipop project team 
, a research team focused on the modeling and the simulation of nonsmooth dynamical systems.
STRMTG is a national technical agency that is part of the French Environment, Energy and the Sea Ministry which is in charge of ropeway and guided transport safety.

Practical aspects:
− Location: INRIA Centre de recherche Grenoble Rhone–Alpes.  Inovallee de Montbonnot, 655, Avenue de l’Europe, 38334 Saint Ismier Cedex.
− Duration : 18 months.
− Salary: around 2150 euros net per months&



Application:
The applicant must send a CV and recommendation letters to Vincent Acary vincent.acary@inria.fr and Mathieu Weiss mathieu.weiss@developpement-durable.gouv.fr

Description de l’offre

Offre de post-doctorat : Probabilistic models of broadband seismic signals conditioned by direct simulation in the low frequency range and deep learning techniques in the high frequency range à CentraleSupélec, Gif-sur-Yvette, France (16/10/2017)

Duration: 1 year, plus possible renewal for 1 year.
Location: The applicant will join the MSSMat laboratory (http://www.mssmat.ecp.fr), located on the brand new campus of CentraleSupelec, at Gif-sur-Yvette, France.
Net Salary : 2200 euros net per month (possibilities for cheap housing close to campus available upon request).
Qualifications: We seek for candidates with excellent skills in numerical methods, computational science, and probabilistic modeling. An experience in mechanics or wave propagation would be appreciated, but not compulsory.
Application: Applicants should send their curriculum vitae and statement of interest, or questions, to Didier Clouteau (didier.clouteau@centralesupelec.fr), Regis Cottereau (regis&#h2e;&+xv3;ottereau@centralesupelec.fr), Fernando Lopez-Caballero (fernando.lopez-caballero@centralesupelec.fr)

Description de l’offre

Offre de post-doctorat : Solveur transitoire surface libre/structure pour EMR Ă  IRDL FRE CNRS 3744 , Lorient (06/07/2017)

Project Title: Innovative numerical methods for the dynamic behavior of a structure in interaction with a free surface
Research Fields: Computational Fluid Dynamic; Fluid Structure Interaction; free surface; high order numerical method; temporal integration numerical scheme; Renewable Marine Energy
Research Laboratory:  Institut de Recherche Dupuy de LÎme<
Work Place: Lorient, FR
UBL Research Department: Industrie
Heads of the Scientific Project: Jean-Marc Cadou (HDR), Yann Guevel, Gregory Girault
Offer type: postdoctoral researcher 18 months (in which 12 months on UBL funding)
Hiring Institution: Université Bretagne Sud
Monthly net salary: 2 300€
Job Starting Date: possibly from 1 nov. 2017 to 1 mar. 2018<

Description de l’offre

http://irdl.fr/index.php/offre-de-post-doc-ingenieurs-techniciens/

Offre de post-doctorat au LTDS (Ecole Centrale de Lyon) ÉCULLY dans le cadre du projet ARPE : Acoustique et vibRation des Pompes à vidE (14/06/2017)

Sujet : ModĂ©lisation dynamique non linĂ©aire de la chaĂźne cinĂ©matique d’une pompe Ă  vide

Compétences recherchées :
Dynamique non linéaire, vibrations, vibroacoustique.
Modélisation numérique.
Maitrise de MATLAB, qui constitue l’environnement dans lequel les outils logiciels existants sont dĂ©veloppĂ©s.

Durée : septembre 2017 à juin 2018.
Lieu : LTDS (Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69 134 ÉCULLY cedex).
Salaire : entre 2000 et 2200 euros net par mois.

Contact :
Emmanuel RIGAUD emmanuel.rigaud@ec-lyon.fr
Maßtre de Conférences HDR
Directeur du LabCom LADAGE (LA boratoire de Dynamique des engrenAGEs)
LTDS – École Centrale de Lyon – BĂątiment TMM23 36 avenue Guy de Collongue 69134 ECULLY Cedex

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Offre de post-doctorat au LaMCoS (INSA-Lyon) dans le cadre du projet MELTED au LAMCOS, INSA-Lyon (10/03/2017)

Sujet : DĂ©veloppement d’un outil numĂ©rique pour le pilotage virtuel des procĂ©dĂ©s de fabrication additive mĂ©tal par rĂ©duction de modĂšles

Personnes Ă  contacter :
Nawfal BLAL, MCF, LaMCoS (nawfal.blal@insa-lyon.fr)
Thomas ELGUEDJ, MCF HDR LaMCoS (thomas.elguedj@insa-lyon.fr)
Arnaud DUVAL, IR CNRS , LaMCoS (arnaud.duval@insa-lyon.fr)

Contexte :
MELTED (MaĂźtrisE de la quaLiTĂ© des piĂšcEs issues de fabrication aDditive) est un projet financĂ© par l’Institut CARNOT i@L rassemblant diffĂ©rents partenaires acadĂ©miques et industriels de la rĂ©gion Lyol-Saiot%Étienne. Il est dĂ©diĂ© aux technologies de fabrication additive de type SLM (Selective Laser Melting) et DMD (Direct Metal Deposition) pour des matĂ©riaux mĂ©talliques, technologies qui permettent de fabriquer des matĂ©riaux innovants sur mesureavec de hautes performances et valeurs ajoutĂ©es. Dans l’objectif de mieux prĂ©dire la qualitĂ© des piĂšces obtenuespar ces procĂ©dĂ©s, il est important de bien apprĂ©hender l’influence des diffĂ©rents paramĂštres mis en jeu (puissance laser, vitesse de balayage, dĂ©bit de poudre…). Des simulations numĂ©riques prĂ©dictives nĂ©cessiteraient des temps de calculs coĂ»teux Ă  cause des aspects non-linĂ©aires et multi-physiques. Le recours Ă  des simulations en temps rĂ©el s’avĂšre ainsi prometteur, efficace et permettrait un gain considĂ©rable en temps de calcul et in fine un pilotage en temps rĂ©el de ces procĂ©dĂ©s.

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Offre de Post-Doctorat au LMA ou au LAMCOS Ă  Marseille (02/03/2017)

Missions principales
Sur la base d’un modĂšle thermomĂ©canique des TTS dĂ©veloppĂ© par le laboratoire LMA dans le code Ă©lĂ©ments finis Aster (thĂšse de GrĂ©gory ANTONI en 2010), les travaux consistent Ă  :

1. Mettre en Ɠuvre le modĂšle dĂ©veloppĂ© et optimiser les algorithmes d’intĂ©grations numĂ©riques associĂ©s
2. Valider ce modÚle numérique à travers une batterie de tests numériques
3. Confronter ce modÚle numérique à des essais expérimentaux qui seront réalisés au sein du laboratoire LAMCOS
4. Proposer des axes d’amĂ©lioration du modĂšle en concertation avec l’équipe d’encadrement

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Post-doctoral position in computational mechanics – ENS Cachan (02/11/2016)

Required Education / Niveau requis : PhD in computational mechanics / applied mathematics
From / Date de début : right away
Duration / Durée : 2 years
Salary : 3136 euros gross per month

Context / Contexte
Domain decomposition methods are well established approaches for solv ing large scale problems on parallel computers. In the field of solid mechanics, non-overlapping approaches such as FETI (Finite Element Tearing and Interconnecting) and BDD (Balancing Domain Decomposition) are recognized as the methods of choice. Given the current trend of increasing computational power by increas ing the number of cores, the adaptation and tuning of these approaches is essential in order to maintain their parallel efficiency while employing large numbers of cores.

Description / Description
In domain decomposition methods, the domain associated with the partial differential equation is decom posed into a possibly large number of subdomains. Local problems are then defined on each subdomain and are solved at each iteration step in order to approximate the inverse of the system’s matrix (stiffness matrix in mechanics for instance). It must be noticed that, in order to obtain a n efficient and scalable parallel algorithm, a coarse problem has to be introduced and solved at each iteration step. Given the evolution of parallel computers to higher core counts, the number of subdomains grows (say several thousands and beyo nd) so that sizes of the local (subdomain) stiffness matrices are reduced. On the one hand, t his notably accelerates the local treatments (mainly factorization of the stiffness matrices). On the other hand, this increases the dimension of the null space and solving the coarse problem will then turn out to constitute a major computational cost. The goal of the post-doctoral internship is to deal with this new challenge by studying novel techniques to solve and approximate the subdomain and the coarse grid problems, and to devise asynchronous scheduling and suitable load balancing strategies. The goal of the project is to help engineers as well as scientists to benefit from the performance of parallel computers with very large number of cores.

Industrial partnership / Partenariat industriel
The post-doctoral position takes part in a wider industrial partnership through the nationally funded project PAMSIM (PArallélisme Massif en SImulation numérique pour la Mécanique aka Massive Parallelism for the Numerical Simulation in Solid Mechanics). In addition to CERFACS, the consortium includes the R&D division of EDF, the LMT laboratory of ENS Cachan and several participating starts-up.

Contact : Ulrich RUEDE, ulrich.ruede@cerfacs.fr

Post-doctoral position en Vibro-acoustique – UniversitĂ© de Cambrige (30/09/2016)

A position exists, for a Research Assistant/Associate in the Department of Engineering, to work on a project funded by the EPSRC concerning the use of experimental data in computational models of noise and vibration. Despite the availability of sophisticated mathematical and computational modelling techniques, some components in a built-up structure can be so complex that it is not possible to produce an ab initio computational model of the whole system, and hence some degree of physical testing is unavoidable. This project will consider how experimental testing can be best performed and utilised in advanced vibro-acoustic models; the experimental work will be based at the University of Salford, while the theoretical and computational work (the current position) will be based at Cambridge. The project has industrial partners (Bentley Motors Ltd, Bruel and Kajaer, Dyson Ltd, and Wave Six LLC) and liaison with these partners will be required throughout the project.

Candidates must have, or be close to obtaining, a PhD in Structural Dynamics.  Expertise in vibration theory and computational methods is a requirement, and some experience of experimental testing is highly desirable.

The post holder will be located in Central Cambridge, Cambridgeshire, UK.

Salary Ranges: Research Assistant: ÂŁ25,023 – ÂŁ28,982, Research Associate: ÂŁ28,982 – ÂŁ37,768.

Fixed-term: The funds for this post are available until 31 May 2019 in the first instance.

Once an offer of employment has been accepted, the successful candidate will be required to undergo a health assessment.

http://www.jobs.ac.uk/job/AOQ395/research-assistant-associate-in-vibration-and-acoustics/

Post-doctoral fellowship proposal at the Laboratoire de Mecanique des Sols, Structures et Materiaux (MSSMat) CentraleSupelec, CNRS « Coupling of numerical solvers for large-scale wavepropagation from source to structure »  (15/09/2016)

Scientific context and objectives

The Spectral Element Method (SEM) is currently very popular for large-scale wave propagation in geophysics, while the Finite Element Method (FEM) is much more widely used for vibration of structures in the context of Earthquake Engineering. This implies in particular that the two communities have developed efficient and validated solvers based on these two methods for their respective cases of interest. These cases of interest consider in particular non-linearities in the mechanical behavior (both for the soil and the structure) and uncertainties in the mechanical parameters. When aiming at computing the full seismic wave propagation path, from the fault to the structure, a natural approach would consist in coupling a SEM solver for the ground and a FEM solver for the structure. However, the space  discretization is different for the two methods (larger elements for high order methods). Likewise, the classical time discretization for the SEM is explicit with very small time steps, while it is implicit for the FEM, with larger time steps. These issues must be mitigated by appropriate numerical treatment at the interface or through a coupling volume. When considering wave propagation over large numbers of processing cores, the questions of synchronous computation and load balancing are essential, and will be of constant concern. The post-doctoral candidate will propose novel approaches for the coupling between SEM and FEM solvers (here SEM3D and Code Aster), and implement them in a High Performance Computing environment.
(…)

Research position

  • Duration : 1 year, plus possible renewal for 1 year.
  • Location : The applicant will join the MSSMat laboratory (http://www.mssmat.ecp.fr), located on the campus of CentraleSupelec, in Ch^atenay-Malabry, France.
  • Net Salary : 2200 euros net per month (possibilities for cheap housing close to campus available upon request).

Qualifications
We seek for candidates with excellent skills in numerical methods and computational science.
An experience in mechanics or wave propagation would be appreciated, but not compulsory.

Application
Applicants should send their curriculum vitae and statement of interest, or questions, to

postdoc_coupling_SINAPS

Post-doctoral position IFPEN « Optimisation des paramĂštres d’une loi matĂ©riau Ă©lasto-viscoplastique utilisĂ©e en calculs de structure » (12/07/2016)

Présentation du sujet :
La production pĂ©troliĂšre reste la premiĂšre source d’Ă©nergie pour les transports et la chimie, et les pĂ©troliers cherchent en permanence Ă  repousser les limites technologiques actuelles pour garantir la production d’hydrocarbures. Cet enjeu impose une meilleure connaissance des matĂ©riaux utilisĂ©s et notamment leur comportement en condition d’utilisation.
Dans ce contexte, IFPEN travaille depuis plusieurs annĂ©es sur la tenue mĂ©canique de la gaine en polymĂšre soumise Ă  un environnement sĂ©vĂšre associĂ© Ă  une pression Ă©levĂ©e de fluide ou de gaz, ainsi qu’à une tempĂ©rature Ă©levĂ©e. Un modĂšle de comportement mĂ©canique permettant de prĂ©dire l’Ă©volution du comportement Ă©lasto-viscoplastique de ce type de matĂ©riau a Ă©tĂ© mis au point. Ce modĂšle de comportement a Ă©tĂ© implĂ©mentĂ© dans un code de calculs de structure par la mĂ©thode des Ă©lĂ©ments finis et a fait ses preuves pour prĂ©dire la dĂ©formation de plusieurs grades de polymĂšres semi-cristallins pour diffĂ©rents Ă©tats de contraintes multiaxiales subis par la structure flexible en service.
Cependant, dans un contexte Ă©conomique concurrentiel, il devient nĂ©cessaire de valider l’utilisation des structures de plus en plus rapidement et facilement. Il est donc nĂ©cessaire pour les matĂ©riaux polymĂšres semi-cristallins de :
‱ Disposer d’une loi de comportement robuste sous des sollicitations toujours plus extrĂȘmes en terme de pression et de tempĂ©rature.
‱ Disposer d’une mĂ©thodologie simple d’identification des paramĂštres de la loi de comportement IFPEN quel que soit le grade de matĂ©riau polymĂšre d’intĂ©rĂȘt.

Profil du candidat :
Le candidat devra avoir une double compĂ©tence Maths/MĂ©ca, voire une thĂšse en mĂ©canique des solides ou sciences des matĂ©riaux, avec une compĂ©tence forte en optimisation et en programmation (Matlab, programmation en C++/Fortran). La connaissance d’un logiciel de
calculs ElĂ©ments Finis sera apprĂ©ciĂ©e (AbaqusTM). Il devra ĂȘtre autonome, pragmatique et ouvert d’esprit.

Lieu :
IFP Energies nouvelles 1-4 avenue de Bois Préau, 92852, Rueil-Malmaison Cedex, FRANCE

Encadrants / Contacts :
Direction Mécanique Appliquée : Dr E. Roguet (eleonore.roguet@ifpen.fr)
Direction Mécatronique et Numérique : Dr Frédéric Delbos (frederic.delbos@ifpen.fr)

Offre en français

Offre en anglais

Post-Doctoral position: « Domain decomposition method for the computation of the effective elastic tensor of random materials », Ecole des Ponts ParisTech (28/06/2016)

Supervisors:
E. CancĂšs (CERMICS, Ecole des Ponts Paristech)
V. Ehrlacher (CERMICS, Ecole des Ponts Paristech)
F. Legoll (Laboratoire Navier, Ecole des Ponts Paristech) | frederic.legoll@enpc.fr | http://navier.enpc.fr/LEGOLL-Frederic

Keywords:
random materials, homogenization, parallel computation, domain decomposition.

The aim of this project is to develop an efficient and original numerical method to compute the effective elastic properties of random heterogeneous materials.

We focus on heterogeneous elastic materials containing small inclusions embedded in a matrix. We assume that these inclusions are randomly distributed in the material. The effective elastic properties of the material are then deterministic, and their computation by a full-field method requires the resolution of an auxiliary problem defined over the entire space. Classical methods consist in considering a large (but finite) statistical elementary volume, on which the auxiliary problem, complemented with appropriate boundary conditions (for instance, periodic boundary conditions), is solved.

In this project, we consider another type of auxiliary problem, defined over the whole space, where the statistical elementary volume is embedded in an exterior infinite homogeneous material. The new problem, which has initially been introduced in a completely different setting, can be seen as a generalization of the Eshelby problem. In some previous work, we have shown, in collaboration with Benjamin Stamm (Aachen university, Germany), how such auxiliary problems can be used to approximate the effective thermal conduction properties.

In this project, the candidate will extend the range of application of the method in order to (i) compute the effective properties of polydisperse materials, (ii) compute the effective mechanical properties of microstructured materials (only thermal problems have been considered until now), …

Announcement.pdf