Surface effects in various bending-based test methods for measuring the elastic property ofnanowires

Abstract

The size-dependent elastic property of nanowires induced by the surface effect isinvestigated by using the core–shell model. The overall effective elastic moduli ofnanowires with regular polygonal cross-sections are unified into a simple and explicitrelation. It is found that the effect of surface elasticity on the elastic moduli can bewell characterized by two dimensionless material and geometric parameters withclear physical meaning. Finite element simulations demonstrate that the derivedtheoretical relation is applicable for all the vibration, bending, and buckling testmethods for measuring the mechanical properties of nanowires. The analyticalresult is also validated by comparing it with relevant experimental measurements.This study is helpful not only for interpreting various phenomena associatedwith size-dependent mechanical properties of nanowires but also for developingand evaluating test techniques for material characterization at the nanoscale.