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Static and Dynamic Analysis of Electrostatically Actuated Highly-Curved Arches
Saibaa, Zakaria
Saibaa, Zakaria
Date
2025-11
Author
Advisor
Type
Thesis
Degree
Citations
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35.232-2025.80a Zakaria Saibaa.pdf
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Description
A Master of Science thesis in Mechanical Engineering by Zakaria Saibaa entitled, “Static and Dynamic Analysis of Electrostatically Actuated Highly-Curved Arches”, submitted in November 2025. Thesis advisor is Dr. Mehdi Ghommem and thesis co-advisor is Dr. Nouha Alcheikh. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
This thesis investigates the linear and nonlinear dynamic behavior of a highly curved, electrostatically actuated MEMS arch resonator and demonstrates its application as a tunable, high-sensitivity pressure sensor. The device is designed based on a comprehensive parametric study of curvature, thickness, and length with an ultimate goal to bring the first antisymmetric and symmetric modes into close proximity and exploit their associated interactions. A finite element (FEM) model is developed and validated. The microbeam’s dynamic response is characterized experimentally using a Laser Doppler Vibrometer setup. In the linear regime, the close spacing between the first two modes facilitates the activation of mode localization when the structure is under varying pressure levels. Tracking the differential frequency between the first antisymmetric and first symmetric modes yields a pressure sensitivity of 174.6 ppm/Torr in the (100 - 760 Torr) range with excellent linearity (R² = 0.9916), significantly exceeding the sensitivities associated with the individual modes. Amplitude-based metric further enhances the sensing performance, reaching 1144.33 ppm/Torr (R² = 0.9951) in the 100-400 Torr range. At lower pressures, the device transitions into a nonlinear regime where a distinct secondary (superharmonic) resonance associated with the third mode emerges. This nonlinear resonance exhibits significantly stronger pressure dependence, achieving sensitivities as high as 1.7×10⁴ ppm/Torr (R² = 0.9901) for differential frequency metrics within the 7–20 Torr pressure range. Moreover, the onset and disappearance of the superharmonic response are shown to be tunable through DC voltage electrostatic loading, enabling active control over the operating range and offering an additional degree of adaptability for sensing applications. Overall, this work demonstrates a single-structure MEMS resonator capable of tunable sensitivity, wide dynamic range, and high stability across linear and nonlinear regimes, establishing it as a strong candidate for compact, high-performance vacuum pressure sensing applications.