Behavioural analysis of the pull-in dynamic transition

Abstract

A careful analysis of the dynamics of the pull-in displacement reveals a metastable transient interval for devices with a Q factor lower than 1.2. The duration of this metastable regime could be up to 20 ms for the structure used in this work, depending on the damping. For typical device dimensions this regime dominates pull-in dynamics. This paper explicitly focuses on the metastable regime. The results of numerical simulations are confirmed with measurement results with the purpose of providing a better understanding of the underlying mechanisms. This may contribute to both improved actuator design and enhanced sensitivity of pressure sensors and accelerometers operating on pull-in time interval measurement. The sensitivity of the pull-in time to external accelerations is 6 × 10−2 s/ms−2 (∼0.6 ms mg−1) for current devices and can be increased by design.

Dynamic simulation of a peristaltic micropump considering coupled fluid flow and structural motion

“…This would likely only require two-dimensional discretization of the fluid chamber domain and therefore be reasonably efficient. Inclusion of post-pull-in electrostatics of diaphragm motion is another possibility for improving the model accuracy [37]. Improved model efficiency, on the other hand, could be accomplished with the development of a full analytical model.…”

Dynamics of a Micro Electrical Mechanical System Subject to Thermoelastic and Squeeze-Film Damping

“…In the latter case the goal is often that of accurately determining [12] and controlling [13] the static and the dynamic pull-in threshold, which could or could not be an unwanted phenomenon depending on the application at hand, and in fully understanding the overall dynamical behaviour in order to improve the performances of the system [1].…”

Time-based micro-g accelerometer with improved damper geometry

“…Repeatedly bringing the microstructure to pull-in, while measuring the pull-in time, enables the measurement of the external acceleration. The advantages of this approach are the low-noise (the nonmechanical noise is set primarily by the resolution of the time measurement, which can be made very high, and therefore, the only noise source is the mechanical-thermal noise) and the low requirements for the capacitive sensing circuit [7]. The main disadvantages are the increase in the system complexity and the low system bandwidth.…”