Patil Sandeep P, Heider Yousef
Institute of General Mechanics, RWTH Aachen University, Templergraben 64, 52062 Aachen, Germany.
Department of Civil Engineering and Engineering Mechanics, Columbia University, New York, NY 10027, USA.
Nanomaterials (Basel). 2019 Jul 22;9(7):1050. doi: 10.3390/nano9071050.
Despite a wide range of current and potential applications, one primary concern of brittle materials is their sudden and swift collapse. This failure phenomenon exhibits an inability of the materials to sustain tension stresses in a predictable and reliable manner. However, advances in the field of fracture mechanics, especially at the nanoscale, have contributed to the understanding of the material response and failure nature to predict most of the potential dangers. In the following contribution, a comprehensive review is carried out on molecular dynamics (MD) simulations of brittle fracture, wherein the method provides new data and exciting insights into fracture mechanism that cannot be obtained easily from theories or experiments on other scales. In the present review, an abstract introduction to MD simulations, advantages, current limitations and their applications to a range of brittle fracture problems are presented. Additionally, a brief discussion highlights the theoretical background of the macroscopic techniques, such as Griffith's criterion, crack tip opening displacement, J-integral and other criteria that can be linked to the fracture mechanical properties at the nanoscale. The main focus of the review is on the recent advances in fracture analysis of highly brittle materials, such as carbon nanotubes, graphene, silicon carbide, amorphous silica, calcium carbonate and silica aerogel at the nanoscale. These materials are presented here due to their extraordinary mechanical properties and a wide scope of applications. The underlying review grants a more extensive unravelling of the fracture behaviour and mechanical properties at the nanoscale of brittle materials.
尽管目前有广泛的应用以及潜在的应用前景，但脆性材料的一个主要问题是它们会突然迅速坍塌。这种失效现象表现为材料无法以可预测和可靠的方式承受拉应力。然而，断裂力学领域的进展，尤其是在纳米尺度上的进展，有助于理解材料的响应和失效本质，从而预测大多数潜在危险。在接下来的内容中，将对脆性断裂的分子动力学（MD）模拟进行全面综述，其中该方法为断裂机制提供了新的数据和令人兴奋的见解，这些是在其他尺度上通过理论或实验难以轻易获得的。在本综述中，将对MD模拟进行简要介绍，包括其优点、当前局限性以及在一系列脆性断裂问题中的应用。此外，简短的讨论将突出宏观技术的理论背景，如格里菲斯准则、裂纹尖端张开位移、J积分以及其他可与纳米尺度断裂力学性能相关联的准则。综述的主要重点是高脆性材料在纳米尺度上断裂分析的最新进展，例如碳纳米管、石墨烯、碳化硅、非晶硅、碳酸钙和二氧化硅气凝胶。介绍这些材料是因为它们具有非凡的力学性能和广泛的应用范围。本综述能更广泛地揭示脆性材料在纳米尺度上的断裂行为和力学性能。
