Abstract
A concurrent multiscale model coupling discrete dislocation dynamics to the finite element method is developed to investigate the plastic mechanism of materials at micron/submicron length scales. In this model, the plastic strain is computed in discrete dislocation dynamics (DDD) and transferred to the finite element method (FEM) to participate in the constitutive law calculation, while the FEM solves the complex boundary problem for DDD simulation. The implementation of the whole coupling scheme takes advantage of user subroutines in the software ABAQUS. The data structures used for information transferring are introduced in detail. Moreover, a FE mesh-based regularization method is proposed to localize the discrete plastic strain to continuum material points. Uniaxial compression tests of single crystal micropillars are performed to validate the developed model. The results indicate the apparent dependence of yield stress on sample size, and its underlying mechanisms are also analyzed.
Highlights
The effect of sample size or shape on material deformation behavior [1–3] has received attention for decades
The key point of the 2D-discrete continuous model (DCM) is that the plastic strain calculated by discrete dislocation dynamics (DDD) directly participates in the constitutive law of the finite element method (FEM)
The DDD module looks to the FEM module to solve the boundary conditions and the FEM module turns to DDD for plastic strain, which determines the constitutive law of the FEM
Summary
The effect of sample size or shape on material deformation behavior [1–3] has received attention for decades. It is necessary to employ a suitable simulation method to reveal the underlying deformation mechanisms of crystal materials at the micro/nano-scale. The plastic deformation of crystals results from its dislocation activities To overcome those limitations, DDD has been proposed by many researchers to capture the size effect and uncover its underlying mechanisms. DDD has been proposed by many researchers to capture the size effect and uncover its underlying mechanisms It omits the direct atomic interactions and takes dislocation as the intrinsic carrier of plastic strain. A concurrent multiscale model coupling DDD to the FEM is developed to investigate the plastic mechanism of materials at micron/submicron length scales.
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