Dynamic Behavior of a Class of Casimir Actuated NEM Switches

Dynamic behavior of a cantilever type nano-switch actuated by pure Casimir force is investigated. Residual surface stress, surface elasticity and intermolecular forces are included in Euler–Bernoulli beam model. Knudsen number dependent squeeze-film air damping model and an asperity-based contact model are incorporated. The proposed model is inherently nonlinear due to interactions between the different nonlinear physics. An approximate analytical approach based on Galerkin’s method has been employed for predicting transient dynamic responses, since no exact solutions are available. Predicted responses show that the beam tip hits the substrate and bounces before making a permanent contact. Actuation of the switch via pure Casimir force is demonstrated for certain length and gap combinations. Initial contact time which governs the switch performance, and the deflections under non-closure condition are also quantified. This study is envisaged to provide useful insights for the future design of Casimir actuated NEM switches.