AN ATOMISTIC-CONTINUUM MULTISCALE METHOD FOR MODELING THE THERMOMECHANICAL BEHAVIOR OF HETEROGENEOUS NANOSTRUCTURES

M Jahanshahi and AR Khoei and N Jafarian and N Heidarzadeh, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, 16, 441-464 (2018).

DOI: 10.1615/IntJMultCompEng.2018027760

In this paper, a computational hierarchical multiscale method is presented to investigate the effect of temperature on mechanical behavior of heterogeneous nanomaterials. The embedded-atom method many- body interatomic potential is employed to investigate the complex interaction between the atoms of copper-aluminum (Cu-Al) alloy at various temperature levels. The thermomechanical properties of Cu-Al alloy are studied at various percentages of Cu-Al. The Nose-Hoover thermostat is proposed for the molecular dynamics analysis. In order to evaluate the equivalent lattice parameter, a weighted average value is used between the lattice parameters of Cu and Al single crystals. The strain energy of the heterogeneous nanostructure is obtained for the multiscale analysis by fitting the polynomial of appropriate order to the data obtained from the representative volume element (RVE) subjected to various types of loading. The variations of ultimate stress, elastic constants, and bulk moduli are computed for the RVEs containing different percentages of Cu-Al alloy at various temperature levels. In order to perform a bridge between the atomistic model and continuum domain, the mechanical properties obtained from the molecular dynamics analysis are transferred to the macroscale level within the multiscale analysis. Finally, several numerical examples are solved to assess the applicability and efficiency of the proposed computational algorithm for studying the behavior of heterogeneous nanostructures in different temperatures.

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