Modelling the Size Effects on the Mechanical Properties of Micro/Nano Structures

Sensors

卷:15

Luis Guillermo Villanueva¹  Seyed Mohsen Safavi²  Amir Musa Abazari²  Ghader Rezazadeh³ 

[1] Advanced NEMS Group, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland;

[2] Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran;

[3] Department of Mechanical Engineering, Urmia University, Urmia 57561-51818, Iran;

关键词: size effect;    Young’s modulus;    residual stress;    couple stress;    grain boundary;    surface elasticity;    surface stress;    length scale parameter;   

DOI  :  10.3390/s151128543

来源: DOAJ

【 摘 要 】

Experiments on micro- and nano-mechanical systems (M/NEMS) have shown that their behavior under bending loads departs in many cases from the classical predictions using Euler-Bernoulli theory and Hooke’s law. This anomalous response has usually been seen as a dependence of the material properties on the size of the structure, in particular thickness. A theoretical model that allows for quantitative understanding and prediction of this size effect is important for the design of M/NEMS. In this paper, we summarize and analyze the five theories that can be found in the literature: Grain Boundary Theory (GBT), Surface Stress Theory (SST), Residual Stress Theory (RST), Couple Stress Theory (CST) and Surface Elasticity Theory (SET). By comparing these theories with experimental data we propose a simplified model combination of CST and SET that properly fits all considered cases, therefore delivering a simple (two parameters) model that can be used to predict the mechanical properties at the nanoscale.

【 授权许可】

Unknown