Abazari Amir Musa, Safavi Seyed Mohsen, Rezazadeh Ghader, Villanueva Luis Guillermo
Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Advanced NEMS Group, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
Sensors (Basel). 2015 Nov 11;15(11):28543-62. doi: 10.3390/s151128543.
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.
对微纳机械系统（M/NEMS）的实验表明，它们在弯曲载荷作用下的行为在许多情况下与使用欧拉 - 伯努利理论和胡克定律的经典预测不同。这种异常响应通常被视为材料特性对结构尺寸，特别是厚度的依赖性。一个能够对这种尺寸效应进行定量理解和预测的理论模型对于M/NEMS的设计至关重要。在本文中，我们总结并分析了文献中可以找到的五种理论：晶界理论（GBT）、表面应力理论（SST）、残余应力理论（RST）、偶应力理论（CST）和表面弹性理论（SET）。通过将这些理论与实验数据进行比较，我们提出了一种CST和SET的简化模型组合，该组合能恰当地拟合所有考虑的情况，从而提供一个简单的（双参数）模型，可用于预测纳米尺度下的力学性能。
