OICC Press Journal of Solid Mechanics 2008-7683 16 3 2024 10 12 A new3D elasticity numerical solution for nonlinear thermo-mechanical bending of orthotropic annular/circular micro/nanoplates using re-modified couple stress & SAPM 246 267 10.60664/jsm.2024.1130439 EN Amirreza Golkarian Ph. D. Student, Science & Research branch, Islamic Azad University, Tehran, Iran Mehrdad Jabbarzadeh Department of Mechanical Engineering, Mashhad branch, Islamic Azad University, Mashhad, Iran Journal Article 2024 10 12 In this research, a new 3D elasticity numerical solution based on the Semi-Analytical Polynomial Method (SAPM) is presented for the nonlinear bending analysis of orthotropic annular/circular micro/nanoplates resting on a Winkler-Pasternak elastic foundation, utilizing re-modified couple stress theory. This is the first report of a 3D elasticity numerical solution specifically based on re-modified couple stress theory. Moreover, while previous 3D analytical solutions based on couple stress theory have primarily focused on the bending of rectangular plates with simply supported edges, this study investigates the nonlinear bending of circular plates under various boundary conditions. Additionally, the variation in thickness under different types of loading (mechanical, thermal, and thermo-mechanical) is reported for the first time. The effects of boundary conditions, couple stress scale parameters, aspect ratio, thickness, loading, and the elastic foundation are examined. Both the increasing and decreasing impacts of scale parameters on deflection are observed in this study.