On the importance of surface elastic contributions to the flexural rigidity of nanowires

Recently published in JMPS:

<http://dx.doi.org/10.1016/j.jmps.2012.07.009>

In the past 5 or so years, analytical studies of surface effects on the mechanical properties of nanostructures such as nanowires have been performed predominantly using one-dimensional models like the Young-Laplace model.   While many such analytical studies have been performed, what has been lacking until now is a systematic study of such analytical models as compared to benchmark atomistic studies for a range of nanomechanical boundary value problems. 

This work performs such a study, and also develops a new theoretical model to calculate the flexural rigidity of nanowires from three-dimensional elasticity theory that incorporates the effects of surface stress and surface elasticity.  It is very similar to a seminal work by Dingreville et al <http://dx.doi.org/10.1016/j.jmps.2005.02.012>, but is different in that it incorporates, through the second moment, the heterogeneous nature of elasticity across the nanowire cross section due to the effects of free surfaces.  We use this approach to study the boundary value problems of surface-stress-induced axial relaxation, transverse vibrations and buckling.  The benchmark comparisons demonstrate the need for a three-dimensional continuum formulation while pointing out the errors introduced by taking a one-dimensional model.