Multiphysic topology optimization of electromechanical microdevices considering pull-in voltage using an electrostatic force filter

Electrostatic actuation is often used in microsystems as it is relatively easy to implement and provides a short response time. However, because of the non-linearity of electrostatic forces, these devices may suffer from an unstable behavior called pull-in effect. Previous work of the authors intended to delay pull-in effect by maximizing pull-in voltage studying a simplified problem where the optimization domain was purely mechanical. The present paper generalizes the approach by considering a multiphysic optimization domain. However, the generalization of the optimization problem is not straightforward as local pull-in modes appear after a few optimization iterations. Therefore, the paper investigates several solutions to prevent the appearance of local pull-in modes.