Surface effects on the elasticity of nanosprings

Nanosprings made of metallic or semiconducting materials hold promise for a wide range of important applications. In this letter, we extend the classical Kirchhoff rod model by incorporating surface effects on the mechanical response of quasi-one-dimensional nanomaterials. The refined model is then employed to derive the elastic constants of a nanospring by accounting for the effect of surface elasticity and residual surface stresses. The results demonstrate that the stiffness of nanosprings may exhibit remarkable dependence on their cross-sections sizes. This study is helpful not only for understanding the size-dependent behavior of nanosprings but also for their applications in micro/nano-electro-mechanical systems.