Surface stress effects on the nonlinear postbuckling characteristics of geometrically imperfect cylindrical nanoshells subjected to axial compression
Surface stress effects on the nonlinear postbuckling characteristics of geometrically imperfect cylindrical nanoshells subjected to axial compression
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DOI：
10.1016/j.ijengsci.2015.10.010
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发表时间：
2016-02
影响因子：
6.6
通讯作者：
S. Sahmani;M. Bahrami;M. M. Aghdam-M.
中科院分区：
文献类型：
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作者：
S. Sahmani;M. Bahrami;M. M. Aghdam-M.
目前的调查的主要目的是预测的非线性扭转屈曲和后屈曲行为的几何不完善的圆柱形纳米壳，包括表面应力的影响。为此，将Gurtin-Murdoch弹性理论与经典壳理论相结合，利用虚功原理，推导了基于von Karman-Donnell型运动非线性的圆柱形纳米壳的尺寸依赖型控制微分方程.随后，通过考虑横向位移和Airy应力函数作为独立变量，边界层理论被投入使用，该理论将表面应力效应与非线性屈曲前变形、大屈曲后挠度和初始几何缺陷结合起来考虑。最后，采用基于两步奇异摄动技术的高效求解方法，获得了与尺寸相关的纳米壳后屈曲平衡路径。结果表明，在后屈曲载荷最小点后，随着扭转载荷的增加，理想和非理想纳米壳的后屈曲载荷-挠度曲线的差异趋于减小.
The prime aim of the current investigation is to predict the nonlinear torsional buckling and postbuckling behavior of geometrically imperfect cylindrical nanoshells including surface stress effects. To this end, the size-dependent governing differential equations of cylindrical nanoshell based on von Karman–Donnell-type of kinematic nonlinearity are derived using a combination of Gurtin–Murdoch elasticity theory and the classical shell theory, and employing the principle of virtual work. Subsequently, by considering the transverse displacement and Airy stress function as independent variables, a boundary layer theory is put to use which takes surface stress effects into account in conjunction with the nonlinear prebuckling deformations, large postbuckling deflections and initial geometric imperfection. Finally, an efficient solution methodology based on a two-stepped singular perturbation technique is conducted to obtain the size-dependent postbuckling equilibrium paths of nanoshells. It is revealed that after the minimum point of postbuckling load, by increasing the value of applied torsional load, the difference between postbuckling load-deflection curves corresponding to the perfect and imperfect nanoshells tends to decrease.