OICC Press Journal of Solid Mechanics 2008-7683 11 5 2019 12 30 Pull-In Instability of MSGT Piezoelectric Polymeric FG-SWCNTs Reinforced Nanocomposite Considering Surface Stress Effect 759 777 EN A Ghorbanpour Arani Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran----Institute of Nanoscience & Nanotechnology, University of Kashan, Kashan, Iran B Rousta Navi Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran M Mohammadimehr Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran S Niknejad Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran A.A Ghorbanpour Arani School of Mechnical Engineering, College of Engineering, University of Tehran, Tehran, Iran A Hosseinpour Department of Mechanical Engineering and Engineering Science,University of North Carolina at Charlotte, USA Journal Article 2019 12 30 In this paper, the pull-in instability of piezoelectric polymeric nanocomposite plates reinforced by functionally graded single-walled carbon nanotubes (FG-SWCNTs) based on modified strain gradient theory (MSGT) is investigated. Various types of SWCNTs are distributed in piezoelectric polymeric plate and also surface stress effect is considered in this research. The piezoelectric polymeric nanocomposite plate is subjected to electro-magneto-mechanical loadings. The nonlinear governing equations are derived from Hamilton's principle. Then, pull-in voltage and natural frequency of the piezoelectric polymeric nanocomposite plates are calculated by Newton-Raphson method. There is a good agreement between the obtained and other researcher results. The results show that the pull-in voltage and natural frequency increase with increasing of applied voltage, magnetic field, FG-SWCNTs orientation angle and small scale parameters and decrease with increasing of van der Waals and Casimir forces, residual surface stress constant. Furthermore, highest and lowest pull-in voltages are belonging to FG-X and FG-O distribution types of SWCNTs.