Effect of the centrifugal force on the electromechanical instability of U-shaped and double-sided sensors made of cylindrical nanowires

Abstract

Beam-type micro/nano-electromechanical systems (MEMS/NEMS) are increasingly used in several branches of engineering and science, i.e. mechanics, chemistry, optics, biology, photonics, electronics, etc. Modeling of the electromechanical stability of NEMS is crucial for the reliable design, fabrication and operation of these devices. Many researchers have investigated the pull-in instability of NEMS devices [1-5]. Although there are many articles focused on modeling the pull-in instability of the conventional NEMS with a simple beam-type electrode [6, 7], few efforts have been made for modeling this phenomenon in less conventional systems such as the U-shaped and double-sided NEMS. In this regard, the present research is devoted to the theoretical study of the electromechanical performance of U-shaped and double-sided cantilever NEMS sensors. The U-shaped configuration consists of two parallel cantilever micro/nano-beams with a rigid plate attached to their free ends. Recently, several studies have investigated the limitations and potential of the U-shaped MEMS/ NEMS as sensors [8], actuators [9], and switches [8-11]. Qian et al. [10] developed a U-shaped nanoelectromechanical switch consisting of a capacitive plate supported by two silicon nanowires. They presented several remarkable advantages of the U-shaped switch such as decreasing the Abstract The U-shaped and double-sided nanostructures are promising for developing miniature angular speed sensors. While the electromechanical instability of conventional beam-type nanostructures has been extensively addressed in the literature, few researchers have investigated this phenomenon in the double-sided and U-shaped sensors. In this regard, the present work demonstrates the effect of the centrifugal force on the pull-in performance of the double-sided and U-shaped sensors fabricated from cylindrical nanowire and operated in the van der Waals (vdW) regime. Based on the modified couple stress theory, the size-dependent constitutive equations of the sensors are derived. The governing equations are solved by two different approaches, i.e. the analytic Duan-Adomian method and the numerical differential quadrature method. The influences of the vdW and centrifugal forces, geometric Communicated by Eduardo Alberto Fancello.

Dynamic instability analysis of U-shaped electromechanical nano-sensor operated in vdW regime

“…The U-shaped NEMS are made of two parallel cantilever micro/nano-beams with a rigid plate attached to theirs free ends. The U-shaped MEMS/NEMS are used for developing new generation of miniature sensors, actuators and switches [7][8][9][10]. Qian et al applied a U-shaped NEMS consist of a capacitive rigid plate supported by two silicon nanowires.…”