Abstract Defects present in the structure of nanostructures strongly affect and determine their performance, especially at high loadings and temperatures. Herein, molecular dynamics simulation (MD) was employed to theoretically pattern the fracture toughness, mechanical properties and crack propagation behavior of the defective monolayers of beryllium oxide graphene-like nanostructures (BeOGLNSs) subjected to some shape defects. The significance of this work lies in the ability to analyzing the mechanical behavior of BeOGLNSs as a key semiconductive structure with high bandgap, possessing great potential for the usage in electronics industry. Using Tersoff potential and periodic boundary conditions, samples of various kinds of defects were modeled to examine their mechanical properties as well as toughness varying the temperature. The results revealed that the mechanical properties of both pristine and defective BeOGLNSs were decreased by increasing the temperature as well as the dimensions of the defects. The Young’s modulus of the nanosheets with the crack length of 150 A, circular and square notches of diameters 150 A decreased at room temperature by about 66%, 77%, and 64%, respectively. A similar behavior was observed for the failure stress and failure strain. Moreover, higher stress concentration in the corners was the reason why the samples with square defects revealed the weakest properties. Furthermore, stress intensity factor of BeGLONSs was increased by enlargement of the crack dimension. Eventually, the defects were propagated along a direction perpendicular to the stress loading, while the detrimental effect of temperature on the failure stress was lowered once the dimension of the defect increased.

中文翻译：

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纳米级氧化铍类石墨烯结构的断裂韧性和裂纹扩展行为：分子动力学模拟分析

摘要 纳米结构结构中存在的缺陷会强烈影响并决定其性能，尤其是在高负载和高温度下。在本文中，分子动力学模拟 (MD) 被用于理论上模拟氧化铍类石墨烯纳米结构 (BeOGLNS) 的缺陷单层的断裂韧性、机械性能和裂纹扩展行为，这些结构具有一些形状缺陷。这项工作的意义在于能够分析 BeOGLNS 作为具有高带隙的关键半导体结构的机械行为，在电子工业中具有巨大的应用潜力。使用 Tersoff 势和周期性边界条件，对各种缺陷的样品进行建模，以检查它们的机械性能以及随温度变化的韧性。结果表明，原始和有缺陷的 BeOGLNS 的机械性能随着温度的升高和缺陷尺寸的增加而降低。裂纹长度为 150 A、直径为 150 A 的圆形和方形缺口的纳米片的杨氏模量在室温下分别降低了约 66%、77% 和 64%。对于失效应力和失效应变，观察到类似的行为。此外，角落处较高的应力集中是具有方形缺陷的样品显示出最弱性能的原因。此外，BeGLONSs 的应力强度因子通过裂纹尺寸的扩大而增加。最终，缺陷沿垂直于应力加载的方向传播，