A FFT-based numerical implementation of mesoscale field dislocation mechanics: Application to two-phase laminates
- Univ. de Lorraine, Metz (France)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
In this study, we present an enhanced crystal plasticity elasto-viscoplastic fast Fourier transform (EVPFFT) formulation coupled with a phenomenological Mesoscale Field Dislocation Mechanics (MFDM) theory here named MFDM-EVPFFT formulation. In contrast with classic CP-EVPFFT, the model is able to tackle plastic flow and hardening due to polar dislocation density distributions or geometrically necessary dislocations (GNDs) in addition to statistically stored dislocations (SSDs). The model also considers GND mobility through a GND density evolution law numerically solved with a recently developed filtered spectral approach, which is here coupled with stress equilibrium. The discrete Fourier transform method combined with finite differences is applied to solve both lattice incompatibility and Lippmann-Schwinger equations in an augmented Lagrangian numerical scheme. Numerical results are presented for two-phase laminate composites with plastic channels and elastic second phase. It is shown that both GND densities and slip constraint at phase boundaries influence the overall and local hardening behavior. In contrast with the CP-EVPFFT formulation, a channel size effect is predicted on the shear flow stress with the present MFDM-EVPFFT formulation. The size effect originates from the progressive formation of continuous screw GND pile-ups from phase boundaries to the channel center. The effect of GND mean free path on local and global responses is also examined for the two-phase composite.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- LDRD; USDOE
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1493559
- Report Number(s):
- LA-UR--18-29918
- Journal Information:
- International Journal of Solids and Structures, Journal Name: International Journal of Solids and Structures Vol. 184; ISSN 0020-7683
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
A numerical study of reversible plasticity using continuum dislocation mechanics
Particle interspacing effects on the mechanical behavior of a Fe–TiB2 metal matrix composite using FFT-based mesoscopic field dislocation mechanics