Advances in Materials Science and Engineering (Jan 2017)

Coupling Strategies Investigation of Hybrid Atomistic-Continuum Method Based on State Variable Coupling

  • Qian Wang,
  • Xiao-Guang Ren,
  • Xin-Hai Xu,
  • Chao Li,
  • Hong-Yu Ji,
  • Xue-Jun Yang

DOI
https://doi.org/10.1155/2017/1014636
Journal volume & issue
Vol. 2017

Abstract

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Different configurations of coupling strategies influence greatly the accuracy and convergence of the simulation results in the hybrid atomistic-continuum method. This study aims to quantitatively investigate this effect and offer the guidance on how to choose the proper configuration of coupling strategies in the hybrid atomistic-continuum method. We first propose a hybrid molecular dynamics- (MD-) continuum solver in LAMMPS and OpenFOAM that exchanges state variables between the atomistic region and the continuum region and evaluate different configurations of coupling strategies using the sudden start Couette flow, aiming to find the preferable configuration that delivers better accuracy and efficiency. The major findings are as follows: (1) the C→A region plays the most important role in the overlap region and the “4-layer-1” combination achieves the best precision with a fixed width of the overlap region; (2) the data exchanging operation only needs a few sampling points closer to the occasions of interactions and decreasing the coupling exchange operations can reduce the computational load with acceptable errors; (3) the nonperiodic boundary force model with a smoothing parameter of 0.1 and a finer parameter of 20 can not only achieve the minimum disturbance near the MD-continuum interface but also keep the simulation precision.