Influence of surface energy on the non-linear pull-in instability of nano-switches

• The non-linear pull-in instability of nano-switches with surface energy is studied.
• Surface energy and geometrically non-linear strain are considered simultaneously.
• The effect of surface energy on pull-in voltage depends on the size of nano-switch.
• The effect of Casimir force on pull-in voltage weakens as the initial gap increases.

This paper investigates the pull-in instability of a nano-switch under electrostatic and intermolecular Casimir forces. The analysis is based on the geometrically non-linear Euler–Bernoulli beam theory with consideration of the surface energy. Through differential quadrature method (DQM), the pull-in voltages of the nano-switch are obtained. Results show that the effect of surface energy and geometrically non-linear deformation on the pull-in voltage depends on the length, height and initial gap of the nano-switch. In addition, the effect of intermolecular Casimir force on the pull-in voltage weakens as the initial gap increases.