We study the mechanical oscillations for a novel model of a graphene-based electrostatic parallel plates micro actuator introduced by Wei et al.(2017), considering damping effects when a periodic voltage with alternating current is applied. Our analysis starts from recent results about this MEMS model with constant voltage, and provides new insights on the periodic mechanical responses for a variable input voltage. We derive sufficient conditions on the system physical components for which periodic oscillations with constant sign exist together with their stability properties. Specifically, under some conditions, the existence of three periodic solutions is established, one of them is negative and the others are positive in sign. The positive one nearby the origin is asymptotically locally stable, whilst the other two are unstable. Additionally, we prove that no further constant sign periodic solutions can be found. The existence of periodic solutions is approached from direct and reverse order Lower and Upper Solutions Method, and the stability assertions are derived from the Liapounoff-Zukovskii criteria for Hill's equations and the linearization principle. Theoretical results are complemented by numerical simulations and numerical continuation results. Furthermore, these numerical simulations evidence the robustness of the graphene-based MEMS model over the traditional ones.