General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DES-24-0205
Thesis topic details
Category
Engineering science
Thesis topics
Robust regularized damage mechanics formulations based on the 'Lip-field' approach for the simulation of quasi-brittle materials structures: application to civil engineering structures
Contract
Thèse
Job description
Cracking prediction of concrete structures is a significant challenge in structural mechanics. Models formulated within the framework of continuum damage mechanics are generally used to model these problems. When the material softens, however, the solution to the equilibrium problem is no longer unique. In the context of the finite element method, this leads to a pathological dependence on the finite element mesh used to discretize the computational domain. The Lip-field approach introduces a new way to avoid spurious localizations and recover mesh independence. The idea is to impose a Lipschitz regularity on the internal variables controlling material softening. The solution to the problem is sought by minimizing an incremental potential, which is a function of displacement and damage. Such potential being convex with respect to each of the variables separately, an alternating minimization approach is used to solve the problem. At present, the use of the Lip-field method for solving large-size problems (structural scale) remains quite tricky, mainly due to the prohibitive computational costs of the alternating minimization solver. The aim of the Ph.D. thesis is to propose several improvements to the theoretical and numerical formulation (e.g., parallel computing, new discretization methods) of the problem, aiming to reduce the computation time of each step of the alternating minimization process (and mainly of the constrained minimization problem for computing the damage field). The Lip-field formulation will be applied finally to the simulation of reinforced concrete structures under quasi-static and dynamic loadings.
University / doctoral school
SCIENCES DE L'INGENIERIE ET DES SYSTEMES (SIS)
Ecole Centrale Nantes
Thesis topic location
Site
Saclay
Requester
Position start date
01/09/2024
Person to be contacted by the applicant
RASTIELLO Giuseppe giuseppe.rastiello@cea.fr
CEA
DES/DM2S/SEMT/EMSI
CEA Saclay, bâtiment 603, point courrier n°112, 91191 Gif-sur-Yvette Cedex
01 69 08 91 62
Tutor / Responsible thesis director
MOES Nicolas nicolas.moes@ec-nantes.fr
Ecole Centrale de Nantes
Institut de recherche en Génie Civil et Mécanique, UMR CNRS 6183 (CNRS/École Centrale de Nantes/Université de Nantes)
1 rue de la Noë BP 92101, 44321 Nantes Cedex 3 - FRANCE
02 40 37 68 22
En savoir plus
https://orcid.org/0000-0003-2970-6755
https://scholar.google.com/citations?user=rC0o2lEAAAAJ&hl=en