Size effects on stability and self-instability of non-uniform nanobeams with consideration of surface effects

Micro & nano letters

article

Abbas Assadi¹  Mostafa Nazemizadeh¹ 

[1] Faculty of Mechanics, Malek-Ashtar University of Technology

关键词: buckling;    Young's modulus;    beams (structures);    nanostructured materials;    internal stresses;    elasticity;    aluminium;    silicon;    elemental semiconductors;    surface stress;    size effect;    step-wise nanobeam;    size effects;    nonuniform nanobeams;    size-dependent stability;    surface elasticity theory;    buckling;    negative surface residual stresses;    positive surface residual stresses;    Young's modulus;    self-instability;    governing equation;    boundary conditions;    Al;    Si;   

DOI  :  10.1049/mnl.2020.0262

学科分类：计算机科学（综合）

来源: Wiley

【 摘 要 】

In this work, size-dependent stability and self-instability of non-uniform nanobeams are studied with consideration of the surface elasticity theory. The nanobeams are modelled as step-wise beams and the governing equation of the nanobeam is solved for different boundary conditions. At first, a backward formulation is developed to calculate the effective Young's modulus to compare it with experimental results. Wide ranges of numerical results are presented for buckling load and self-instability of Al and Si nanobeams with positive and negative surface properties. The obtained results indicate that the selection of the number of steps in the presence of surface effects has a considerable impact on the mechanical behaviour of non-uniform nanobeams. In addition, the aspect ratio of one section of a step-wise nanobeam with negative surface residual stresses can make the whole structure self-instable. The results for effective Young's modulus are compared with previous experiments and satisfactory agreement is illustrated.

【 授权许可】

CC BY|CC BY-ND|CC BY-NC|CC BY-NC-ND