A FFT-based approach for Mesoscale Field Dislocation Mechanics: application to grain size effect in polycrystals

Stéphane Berbenni (1, 2) , V. Taupin (3) , Ricardo A Lebensohn (3)

1 Labex DAMAS
2 LEM3 - Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux
3 LANL - Los Alamos National Laboratory

A crystal elasto-viscoplastic FFT formulation coupled with the Mesoscale Field Dislocation Mechanics (MFDM) theory is presented. This MFDM-EVPFFT approach accounts for plastic flow and hardening from densities of geometrically necessary dislocations (GND) in addition to statistically stored dislocations (SSD). It is shown on 3D periodic Voronoi polycrystals that GND densities modify both intra-granular incompatible fields and stresses, which are at the origin of a grain size dependent flow stress of the Hall-Petch type.

Mots clés: crystal plasticity; elasto-viscoplastic; field dislocation mechanics; FFT; grain size effect

Domaines: Mécanique [physics.med-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des solides [physics.class-ph]

Stéphane Berbenni, V. Taupin, Ricardo A Lebensohn. A FFT-based approach for Mesoscale Field Dislocation Mechanics: application to grain size effect in polycrystals. CSMA 2019, 14ème Colloque National en Calcul des Structures, May 2019, Giens, France. ⟨hal-02360499⟩