PhD opportunities

Multiscale computational approach for severe deformation processes in crystalline aggregates

Thesis proposal

Area of expertiseMechanics
Doctoral SchoolSMI - Sciences des Mtiers de l'Ingnieur
SupervisorM. Samuel FOREST
Co-supervisorM. Arjen ROOS
Research unitCentre of materials
ContactFOREST Samuel
KeywordsCrystal plasticity, Strain gradient plasticity, Large deformations, Finite element
AbstractThe PhD student will work on a finite deformation crystal plasticity model implemented in the implicit finite element code Zset (common code for MINES ParosTech-SafranTech). He will identify the material parameters for the titanium alloy for which experimental results are available within the project, using simulations of representative volume elements of polycrystals. The model will be also implemented in an explicit code for comparison. Finite element simulations will be performed at large strains in order to investigate the possibility of remeshing and field transfer in the context of crystal plasticity.

In a second step, the crystal plasticity framework will be extended to incorporate the effect of Geometrically Necessary Dislocations (GND) that arise in the presence of strong strain gradients. Two types of strain gradient crystal plasticity models will be considered. The first one is an available strain gradient crystal plasticity model incorporating the gradient of cumulative slip in the formulation. The corresponding implicit code is already available at finite strains. This first approach will be extended to incorporate the full dislocation density tensor (GND tensor) defined as the curl of the plastic deformation field. Size effects associated with grain size and strong strain gradients induced by the loading will be investigated and compared to experimental results obtained within the project.

The last stage will be devoted to the identification of a homogenized polycrystal model at large strains from the simulations of the polycrystalline aggregates. This reduced model will be used to determine the effect of the crystallographic texture and its evolution during straining. A first version of the model is available and will be extended to incorporate suitable constitutive laws including dislocation densities and characteristic lengths deduced from the full field simulations. The results of the homogenization model will serve forthe calibration of more macroscopic models not based on crystal plasticity.
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)
Good analytical, synthesis, innovation and communication skills.
Qualities of adaptability and creativity. Teaching skills. Motivation for research activity.
Coherent professional project.

The ESR (Early Stage Researcher) may be a national of a Member State, of an Associated Country or of any Third Country.
The ESR must not have resided or carried out her/his main activity (work, studies, etc.) in the country of her/his host organization for more than 12 months in the 3 years immediately prior to her/his recruitment.
Holds a Masters degree or equivalent, which formally entitles to embark on a Doctorate.
Does not holds a PhD degree.

Excellent Master degree in mechanical engineering, material science, computer science or related disciplines
Strong interest in computational mechanics related to material science and working knowledge in the field of metallic alloys, fields measuring
Significant laboratory experience in finite element computing and coding (C++)
Strong background in plasticity theory and computation
Familiarity with lab equipment, including chemical handling procedures and attention to detail as well as environmental, health and safety (EHS) requirements
Excellent communication skills and willingness to work in collaborative projects with multiple partners
Very good English language skills
Self-motivation and the ability to achieve goals independently as well as to contribute effectively to the team

Applicants should supply the following :

- a detailed resume
- 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

to be sent to
FundingContrat de recherche
PartnershipPartenaire industriel : Safran Tech within Horizon 2020 ITN Project ENABLE

Type de financement : Horizon 2020 ITN Project ENABLE