Nonlinear beam formulation incorporating surface energy and size effect:application in nano-bridges

作     者：A.KOOCHI H.HOSSEINI-TOUDESHKY M.ABADYAN 

作者机构：Department of Aerospace EngineeringAmirkabir University of TechnologyTehran 15875-4413Iran Mechanical Engineering GroupShahrekord BranchIslamic Azad UniversityShahrekord ***Iran 

出 版 物：《Applied Mathematics and Mechanics(English Edition)》 (应用数学和力学（英文版）)

年 卷 期：2016年第37卷第5期

页      面：583-600页

核心收录：

学科分类：080805[工学-电工理论与新技术] 0808[工学-电气工程] 07[理学] 070205[理学-凝聚态物理] 08[工学] 080202[工学-机械电子工程] 080401[工学-精密仪器及机械] 080501[工学-材料物理与化学] 0804[工学-仪器科学与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0811[工学-控制科学与工程] 0702[理学-物理学] 

主　　题：surface energy size effect nonlinear beam formulation electromechanicalnano-bridge pull-in instability 

摘      要：A nonlinear beam formulation is presented based on the Gurtin-Murdoch surface elasticity and the modified couple stress theory. The developed model theoretically takes into account coupled effects of the energy of surface layer and microstructures size- dependency. The mid-plane stretching of a beam is incorporated using von-Karman nonlinear strains. Hamilton＇s principle is used to determine the nonlinear governing equation of motion and the corresponding boundary conditions. As a case study, pull-in instability of an electromechanical nano-bridge structure is studied using the proposed formulation. The nonlinear governing equation is solved by the analytical reduced order method （ROM） as well as the numerical solution. Effects of various parameters including surface layer, size dependency, dispersion forces, and structural damping on the pull- in parameters of the nano-bridges are discussed. Comparison of the results with the literature reveals capability of the present model in demonstrating the impact of nano- scale phenomena on the pull-in threshold of the nano-bridges.