The Effects of Initial Rise and Axial Loads on MEMS Arches

Abstract

Arch microbeams have been utilized and proposed for many uses over the past few years due to their large tunability and bistability. However, recent experimental data have shown different mechanical behaviors of arches when subjected to axial loads, i.e., their stiffness may increase or decrease with applied axial loads. This paper aims to investigate in depth, the influence of the competing effects of initial rise and axial loads on the mechanical behavior of micromachined arches; mainly their static deflection and resonant frequencies. Based on analytical solutions, the static response and eigenvalue problems are analyzed for various values of initial rises and axial loads. Universal curves showing the variation of the first three resonance frequencies of the arch are generated for various values of initial rise under both tensile and compressive axial loads. This study shows that increasing the tensile or compressive axial loads for different values of initial rise may lead to either increase in the stiffness of the beam or initial decrease in the stiffness, which later increases as the axial load is increased depending on the dominant effect of the initial rise of the arch and the axial load. The obtained universal curves represent useful design tools to predict the tunability of arches under axial loads for various values of initial rises. The use of the universal curves is demonstrated with an experimental case study. Analytical formulation is developed to predict the point of minimum where the trend of the resonance frequency versus axial loads changes qualitatively due to the competing effects of axial loads and initial curvature.

Highly sensitive and wide-range resonant pressure sensor based on the veering phenomenon

“…The basic theory behind the frequency tuning comes from the effect of the induced compressive axial load, due to the heating of the arch from electrothermal actuation, which increases the curvature of the arch, and hence its stiffness. An analytical study of this effect was presented in [23]. In addition, we showed in [21] that by carefully choosing the geometrical parameters and the initial shape of the arch, the veering phenomenon (avoided-crossing) among the first two symmetric modes can be strongly activated [21].…”

Multi-Inputs and Multi-Outputs Mems Resonator for Complex Logic Operations

“…The frequency decreases until it gets to the critical point after which it increases as the voltage increases. As reported in [13], this observed phenomenon is due to the competing effect between the initial curvature of the arch beam and the applied tensile axial load from the selector.…”

A single MEMS resonator for reconfigurable multifunctional logic gates

“…This dominant effect can be attributed to the low initial curvature of the arches compared to their length. Also in [25], we studied the competing effects among the design parameters on the resonance frequencies and the mid-point deflections of an arch beam. Based on the results and analyses in [25], we selected a shallow arch beam that gives required frequency shifts necessary to perform the logic operations.…”

“…Also in [25], we studied the competing effects among the design parameters on the resonance frequencies and the mid-point deflections of an arch beam. Based on the results and analyses in [25], we selected a shallow arch beam that gives required frequency shifts necessary to perform the logic operations. To experimentally characterize the device, we utilize a network Analyze (E5071C) and the setup shown in Figure 2.…”