A CONTINUUM MECHANICAL SURROGATE MODEL FOR ATOMIC BEAM STRUCTURES

MG Schmidt and AE Ismail and RA Sauer, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, 13, 413-442 (2015).

DOI: 10.1615/IntJMultCompEng.2015013568

Starting from a fully atomistic system, we outline a general approach to obtain an approximate continuum surrogate model incorporating specific kinematic state variables. The continuum mechanical system is furnished with a hyperelastic material model. We then adapt the procedure to slender structures with beam-like character, such as silicon nanowires or carbon nanotubes. The surrogate model can be described as a geometrically exact beam, which can be treated numerically using finite elements. Based on molecular dynamics simulations, we show how to obtain for a given atomistic beam system both a set of suitable deformed states as well as generalized stress and strain measures. Finally, we benchmark the obtained continuum model by assessing its accuracy for a beam coming into contact with an infinite Lennard-Jones wall.

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