A polynomial chaos expansion based molecular dynamics study for probabilistic strength analysis of nano-twinned copper

A Mahata and T Mukhopadhyay and S Adhikari, MATERIALS RESEARCH EXPRESS, 3, 036501 (2016).

DOI: 10.1088/2053-1591/3/3/036501

Nano-twinned structures are mechanically stronger, ductile and stable than its non-twinned form. Wehave investigated the effect of varying twin spacing and twin boundary width (TBW) on the yield strength of the nano-twinned copper in a probabilistic framework. An efficient surrogate modelling approach based on polynomial chaos expansion has been proposed for the analysis. Effectively utilising 15 sets of expensive molecular dynamics simulations, thousands of outputs have been obtained corresponding to different sets of twin spacing and twin width using virtual experiments based on the surrogates. One of the major outcomes of this work is that there exists an optimal combination of twin boundary spacing and twin width until which the strength can be increased and after that critical point the nanowires weaken. This study also reveals that the yield strength of nanotwinned copper is more sensitive toTBWthan twin spacing. Such robust inferences have been possible to be drawn only because of applying the surrogate modelling approach, which makes it feasible to obtain results corresponding to 40 000 combinations of different twin boundary spacing and twin width in a computationally efficient framework.

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