An atomistic-continuum multiscale analysis for heterogeneous nanomaterials and its application in nanoporous gold foams

AR Sameti and AR Khoei, APPLIED MATHEMATICAL MODELLING, 107, 353-378 (2022).

DOI: 10.1016/j.apm.2022.02.029

In this paper, an atomistic-continuum homogenization multiscale method is developed to study the nonlinear behavior of heterogeneous nanomaterials. The atomistic representative volume element (RVE) with vacancy and/or void defects are analyzed by employing the fully atomistic method, in which the nucleation, migration, and elimination of dislocation, as well as the dislocation-vacancy interaction, are captured. The coarse-scale material domain is modeled within the framework of the nonlinear finite element method, and the impression of nanoscale material defects is investigated by upscaling the stress tensor and tangent modulus from the atomistic RVE based on the Hill- Mandel principle. The principle of inter-scale kinematic compatibility is implemented using the periodic boundary condition. The mechanical behavior of atomistic RVE under various deformation modes is elucidated through stress - strain and dislocation density - strain curves. Due to the random nature of defects on the atomistic scale, a statistical procedure is exerted to numerically investigate the effect of influential parameters on the RVE mechanical behavior. Finally, the impression of vacancy and/or nanoscale void defects on the multiscale simulation of coarse-scale materials is illustrated in several numerical examples. The obtained results of the multiscale analysis is also verified with experimental data. Moreover, the compaction behavior of nanoporous gold foam is studied through the proposed multiscale method that highlights a good agreement with the fully atomistic analysis. (c) 2022 Elsevier Inc. All rights reserved.

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