[Liste-proml] 8 juin 2012, séminaire du Labex MS2T

Antoine Jouglet antoine.jouglet at hds.utc.fr
Jeu 24 Mai 09:08:45 CEST 2012


L'ambition du Labex MS2T (Maîtrise de Systèmes de Systèmes 
Technologiques : http://www.utc.fr/labexms2t/) est d’accélérer la levée 
des verrous scientifiques dans les domaines du transport et de la 
mobilité, de la sécurité, de l'ingénierie pour la santé et de 
l'environnement, en favorisant l’émergence d’une communauté scientifique 
internationale autour de la maîtrise des systèmes de systèmes 
technologiques ; ce défi scientifique majeur n’a encore été que peu 
abordé par les équipes académiques, et ne peut être conduit qu’à travers 
une approche pluridisciplinaire.
Dans le cadre de ses séminaires, le Labex MS2T, qui réunit  les UMR 
Heudiasyc (Heuristique et diagnostic des systèmes complexes), BMBI 
(Biomécanique et génie biomédical) et  Roberval (Mécanique Acoustique et 
Matériaux) invite des personnalités de ces trois communautés 
scientifiques à venir présenter leurs travaux dans le but de susciter 
une dynamique de recherche autour de la maîtrise des systèmes de 
systèmes technologiques, et en particulier dans les thèmes affichés par 
le Labex : interactions et coopération entre systèmes, gestion des 
incertitudes, optimisation des systèmes de systèmes, thèmes qui sont 
communs aux laboratoires impliqués.

Le prochain séminaire du Labex MS2T, ouvert à tous, aura lieu le 
vendredi 08 juin 2012 à 10h dans l'amphi Bessel.

A cette occasion, nous aurons le plaisir d'écouter un exposé de 
Francisco CHINESTA,  Professeur à l'Ecole Centrale de Nantes et 
responsable du pôle Matériaux et Procédés de fabrication du GeM ( 
Institut de Recherche en Génie Civil et Mécanique, UMR CNRS - Ecole 
Centrale de Nantes - Université de Nantes).

Francisco CHINESTA est titulaire de la Chaire de la Fondation 
d'entreprise EADS, dont l’objectif est de mettre en place des projets de 
recherche en modélisation et simulation numérique avancées des procédés 
de fabrication des structures composites pour l'industrie aéronautique 
et spatiale  et plus généralement de contribuer à relever les nombreux 
et grands défis technologiques de ces secteurs.

Son exposé portera sur le thème  :

Routes to advanced modeling and simulation of complex materials, 
processes and systems – Revolutionizing future Information and 
communication technologies.


Résumé de l'exposé :

Today many problems in science and engineering remain intractable, in 
spite of the impressive progresses attained in mechanical modelling, 
numerical analysis, discretization techniques and computer science 
during the last decade, because their numerical complexity is simply 
unimaginable. We can distinguish different challenging scenarios:

•     The first one concerns models that are defined in high dimensional 
spaces, usually encountered in quantum chemistry and kinetic theory 
descriptions of complex fluids. Model defined in high dimensional spaces 
suffer the so-called curse of dimensionality.
•     The second problem category involves time-dependent problems not 
necessarily defined in high-dimensional spaces, but whose spectrum of 
characteristic times is so wide that standard incremental time 
discretization techniques cannot be applied.
•     Real time simulators are needed in many applications, e.g. 
surgical simulators. Control, malfunctioning identification and 
reconfiguration of systems also need to run in real time.
•     Problems of the fourth category are defined in degenerate 
geometrical domains, as plate or shell-like domains. Standard grid-based 
3D discretization methods then quickly become impractical, in view of 
the compulsory discretization of the small length scales that yield 
extremely fine meshes.
•     Many problems in process control, parametric modeling, inverse 
identification, and process or shape optimization, usually require, when 
approached with standard techniques, the direct computation of a very 
large number of solutions for particular values of the problem 
parameters.
•     Traditionally, Simulation-based Engineering Sciences relied on the 
use of static data inputs to perform the simulations. A new paradigm 
emerged: Dynamic Data-Driven Application Systems (DDDAS) entails the 
ability to dynamically incorporate data into an executing application.
•     Augmented reality is another area in which efficient (fast and 
accurate) simulation is urgently needed. The idea is supplying in real 
time appropriate information to the reality perceived by the user.
•     Light computing platforms (tablets or smartphones) are appealing 
alternatives to heavy computing platforms that in general are expensive 
and whose use requires technical knowledge.

The main challenge is to address the modeling and simulation of “real” 
models encountered in science and engineering with all their complexity 
from the geometrical and constitutive points of view, some of them never 
until now solved because their computational complexity. These models 
should be solved very fast, in some cases in real time, by using light 
computing platforms. Classical simulation techniques fail to fulfill the 
above requirements. An appealing alternative consist of considering 
off-line solutions of parametric models, in which all the sources of 
variability – loads, boundary conditions, material parameters, 
geometrical parameters, etc. - will be considered as extra-coordinates. 
Thus, by solving only once the resulting multidimensional model, we have 
access to the solution of the model for any value of the parameters 
considered as extra-coordinates. Now, from this general solution 
computed only once and off-line we could perform on-line real time 
post-processing, optimization, inverse analysis, analysis of 
sensibilities, stochastic analysis … by using very light computing 
platforms as for example smartphones. We could also adapt the model 
on-line while its simulation is running within the framework of dynamic 
data-driven application systems – DDDAS. The price to be paid is the 
solution of parametric models defined in high dimensional spaces that 
could involve hundreds of coordinates. The use of the Proper Generalized 
Decomposition that we recently proposed and we are intensively 
developing, allows such solution, because thanks to the separated 
representation of the unknown fields the computational complexity scales 
linearly with the dimensionality, instead of growing exponentially which 
is characteristic of mesh-based discretization techniques. This 
off-line-on-line Proper Generalized Decomposition Based Dynamic 
Data-Driven Application Systems could constitute a new paradigm in 
computational sciences and engineering.

Si vous souhaitez avoir des précisions sur le lieu, votre venue à 
Compiègne, veuillez vous adresser à : laurie.herlin at utc.fr


Antoine Jouglet, Anne Virginie Salsac, Catherine Vayssade - Les 
organisateurs des séminaires du Labex MS2T
Laurie Herlin - Assistante Labex



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