A theoretical analysis of large deformation of nanobeams with surface energy

Nanobeams are widely used in nano-electro-mechanical systems and biotechnology as actuators, transistors, resonators and sensors. In the present paper, we propose a theory to analyze the large deformation of nanobeams with surface effect by the core–shell model and surface-energy-based model. Adopting Euler–Bernoulli beam model and the principle of minimum potential energy, the nonlinear governing equation as well as the boundary conditions is deducted incorporated surface effects and geometric nonlinear deformation. As an example, the postbuckling of nano-cantilever is studied using our theory. The results agree well with the theoretical analysis of surface effects with surface stress. This study helps to understand the influence of the surface effects on the mechanical behavior of nanodevices and also will help in accurately measuring and manufacturing nanodevices and systems based nanowires.