Dynamic bow snap-through in electrostatically actuated microbeams under prestress tuning

A curved bistable microbeam, subjected to electrostatic loading from an electrode facing its concave side, may exhibit bow snap-through ($BST$) at nearly half the voltage ($\approx \! 54\%$) when compared to actuation from the convex side. Previously, it was shown that introducing prestress can enable $BST$ where it is otherwise unattainable. The current work extends the $BST$ condition to include dynamic actuation, thus establishing dynamic bow snap-through ($DBST$) as a viable and sustainable form of actuation, since it can reduce actuation by $\approx \! 10 \! - \! 16\%$. To enable analytical derivation while retaining generality across various loading scenarios, the analysis employs an undamped single-degree-of-freedom reduced-order model obtained via Galerkin's decomposition. The resulting formulation yields a necessary condition for $DBST$, expressed in terms of beam geometry, prestress, and initial conditions, forming a unified condition. Subsequent analysis shows that suddenly applied actuations, combined with prestress, can enable $BST$ over a wider range of parameters, whereas excessive kinetic energy and/or prestress can suppress $DBST$. The proposed condition provides practical design guidance for energy-efficient, low-voltage and non-volatile bistable devices.