PhD opportunities

Simulation of plastic strain localization by Discrete Dislocation Dynamics and crystal plasticity

Thesis proposal

Area of expertiseMechanics
Doctoral SchoolSystems Engineering, Materials, Mechanics, Energy
SupervisorM. Henry PROUDHON
Research unitCentre of materials
ContactPROUDHON Henry
http://www.mat.mines-paristech.fr/Accueil/Propositions-de-theses/
Starting dateOctober 1st 2020
KeywordsDislocation dynamics, crystal plasticity, plastic strain localization, HPC simulation
AbstractUnderstanding the deformation processes leading to the failure of polycrystalline structural materials is one of the key challenges in materials science. Significant progress has been achieved over the past decades, thanks to both cutting-edge experimental characterization techniques and computational methods [1-3]. Still, the localization of plasticity in slip bands and the propagation of plasticity through a polycrystalline aggregate are not fully understood. The investigation of such phenomena is the goal of the ANR project 3DPolyPlast starting in march 2020.

Within the 3DiPolyPlast, this open position will particularly focus on objectives 3 and 4. The electron- and synchrotron-based characterizations carried out in the 2 other Ph. D. projects will be compared to the simulation results performed on digital copies (clones) of the measured 3D grain microstructures. In the proposed multi-scale simulation approach, Discrete Dislocations (DD) simulations will be used in order to better model the individual and collective behaviour of dislocations at the mesoscale. Stress concentration at the origin of strain localization in slip bands is naturally reproduced by DD simulations. Modeling the boundaries in such simulations is non-trivial and will be addressed in the framework of the Discrete-Continuous Model (DCM) which couples crystal plasticity finite element calculations carried out on the full polycrystalline aggregate with DD simulations inside a single grain. This method is based on continuum elasticity theory, which provides the description of the elastic strain field induced by dislocations, their mutual interaction and their interaction with an external stress field [4]. The strong advantage of this method is that stress concentration at the origin of strain localization in slip bands [5] can be accurately simulated by DD calculations.
ProfileEngineer and / or Master of Science - Good level of general and scientific culture. Good level of knowledge of French (B2 level in french is required) and English. (B2 level in english is required) Excellent analytical, synthesis, innovation and communication skills. Qualities of adaptability and creativity. Teaching skills. Motivation for research activity. Coherent professional project.

You must show an appetite for large scale simulations of material behaviour and a will to deeply understand the processes behind material deformation. You will be part of a national project regrouping 4 recognized institutes in the field; 3 different PhD student will interact within the project. The Ph. D. candidate is expected to communicate within the project, at relevant conferences and to publish in international journals. Mastering English writing and very good communication skills is mandatory.

Applicants should supply the following :
a detailed resume
a copy of the identity card or passport
a covering letter explaining the applicants motivation for the position
detailed exam results
two references : the name and contact details of at least two people who could be contacted
to provide an appreciation of the candidate
Your notes of M1, M2
level of English equivalent TOEIC

to be sent to recrutement_these@mat.mines-paristech.fr
FundingFinancement par crdits ANR