Buckling behavior of nanowires predicted by a new surface energy density model

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• 作者：Yin Yao ; Shaohua Chen
• 刊名：Acta Mechanica
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：227
• 期：7
• 页码：1799-1811
• 全文大小：1,598 KB
• 刊物类别：Engineering
• 刊物主题：Theoretical and Applied Mechanics
  Mechanics, Fluids and Thermodynamics
  Continuum Mechanics and Mechanics of Materials
  Structural Mechanics
  Vibration, Dynamical Systems and Control
  Engineering Thermodynamics and Transport Phenomena
  
• 出版者：Springer Wien
• ISSN：1619-6937
• 卷排序：227

文摘

The axial buckling behavior of nanowires is investigated with a new continuum theory, in which the surface effect of nanomaterials is characterized by the surface energy density. Only the surface energy density of bulk materials and the surface relaxation parameter are involved, instead of the surface elastic constants in the classical surface elasticity theory. Two kinds of nanowires with different boundary conditions are discussed. It is demonstrated that the new continuum theory can predict the buckling behavior of nanowires very well. Similar to the prediction of the classical elasticity theory, the critical compressive load of axial buckling of nanowires predicted by the new continuum theory increases with an increasing characteristic length, such as the diameter or height of nanowires. With the same aspect ratio, a nanowire with a rectangular cross section possesses a larger critical buckling load than that with a circular one. However, the surface effect could enhance the critical buckling load not only for a fixed–fixed nanowire but also for a cantilevered one in contrast to the classical elastic model. All the results predicted by the new continuum theory agree well with predictions by the surface elasticity models. The present research not only verifies the validation of the new continuum theory, but also gives a much more convenient characterization of buckling behaviors of nanowires. This should be helpful for the design of nanodevices based on nanomaterials, for example, nanobeams in NEMS or high-precision instruments.