Discrete action micro-actuator optimization

Abstract

Micro-electro-mechanical systems (MEMS) devices are widely used in industry. The micro-actuator is an important component of such devices, transforming external influence into mechanical displacement. The development of a design technique to derive the optimal design parameters for a micro-actuator is a problem of current interest. The present paper describes a technique for determining geometric parameters for a simplified micro-actuator structure (a hemispherical shell), such that under a prescribed critical pressure it will undergo a specified discrete deflection. Such a deflection is commonly referred to as "snap-through". A mathematical model and a Finite Element procedure for the mechanical analysis of a flexible thin-walled shell under large deformation are proposed. Initially the snap-through is modelled as a quasi-static effect, but subsequently, the influence of the inertia is also considered. The optimization procedure was performed using the PSE/MACROS optimization program. The results for an example model numerical optimization are shown.