Imam Hussein University Aerospace Mechanics 2645-5323 21 1 2025 05 22 Analysis of Static behavior, Frequency, and Capacitance of Three Plates Microswitch Using Modified Couple Stress Theory Analysis of Static behavior, Frequency, and Capacitance of Three Plates Microswitch Using Modified Couple Stress Theory 97 108 209631 10.47176/MAJ.2025.1466 FA Karamat Malekzadeh Fard Professor, Faculty of Aerospace Engineering, Malek-e-Ashtar University of Technology, Tehran, Iran 0000-0002-4725-6949 Hamed Mobki Ph.D., Faculty of Mechanical Engineering, Urmia University, Urmia, Iran Alireza Pourmoayed Corresponidng author: Associate Professor, Faculty of Mechanical Engineering, Khatamul-Anbiya Air Defense University, Tehran, Iran 0000-0002-7217-4582 Journal Article 2024 10 22 Considering the importance of the effects of the characteristic length parameter in studying the stability of microswitches, this paper discusses and studies the stability of microswitches by considering this effect and using the improved coupled stress theory. The microswitch studied in this paper is a three-plane microswitch in which the microbeam is suspended between two fixed electrodes. Recently, such microswitches have attracted the attention of some researchers and research has been conducted on the analysis of the static and dynamic behavior of these switches. For this purpose, the governing equation for the dynamic and static behavior of the microswitch is presented using the coupled stress theory and the classical beam theory. To solve the governing equation, which is a nonlinear equation; the stepwise linearization method is used. The results governing the static behavior of the microswitch and the determination of the instability voltage under different voltage ratio conditions are determined and compared using both the coupled stress theory and the classical beam theory. In addition to the above, how the frequency and capacitance of the microswitch change with respect to the applied voltage change are presented and compared using the coupled stress theory and the classical beam theory. Considering the importance of the effects of the characteristic length parameter in studying the stability of microswitches, this paper discusses and studies the stability of microswitches by considering this effect and using the improved coupled stress theory. The microswitch studied in this paper is a three-plane microswitch in which the microbeam is suspended between two fixed electrodes. Recently, such microswitches have attracted the attention of some researchers and research has been conducted on the analysis of the static and dynamic behavior of these switches. For this purpose, the governing equation for the dynamic and static behavior of the microswitch is presented using the coupled stress theory and the classical beam theory. To solve the governing equation, which is a nonlinear equation; the stepwise linearization method is used. The results governing the static behavior of the microswitch and the determination of the instability voltage under different voltage ratio conditions are determined and compared using both the coupled stress theory and the classical beam theory. In addition to the above, how the frequency and capacitance of the microswitch change with respect to the applied voltage change are presented and compared using the coupled stress theory and the classical beam theory. https://maj.ihu.ac.ir/article_209631_fb8420a9fbc9d072cb27147452d58267.pdf