Plastic activity in nanoscratch molecular dynamics simulations of pure aluminum

Atomistic models for friction suffer from the severe length- and time-scale restrictions of molecular dynamics. Even when they yield good qualitative results, it is difficult to draw meaningful quantitative conclusions from them. In this presentation, a novel approach to quantify the scratching work and the energy associated with plastic activity is used. The approach is combined with a statistical criterion to determine the significance of simulation box size, microstructure and sliding rate effects on the friction coefficient. These two methods are applied to a large parametric molecular dynamics study of single-asperity aluminum nano-scratch on mono-crystalline and poly-crystalline substrates. The results show that the simulation size effects are a considerable obstacle to understanding the atomistic origins of friction -- using present-day computing hardware -- as they have a strong influence on the core mechanisms of sliding friction, therefore motivating the development of 3D multi-scale methods for a hybrid nano- and micro-scale description of plasticity.


Presented at:
Society of Engineering Science 49th Annual Technical Meeting, Atlanta, Georgia, USA, October 10-12, 2012
Year:
2012
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 Record created 2013-02-06, last modified 2018-03-17

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