Fracture toughness and crack propagation behavior of nanoscale beryllium oxide graphene-like structures: A molecular dynamics simulation analysis

MZ Dehaghani and AH Mashhadzadeh and A Salmankhani and Z Karami and S Habibzadeh and MR Ganjali and MR Saeb, ENGINEERING FRACTURE MECHANICS, 235, 107194 (2020).

DOI: 10.1016/j.engfracmech.2020.107194

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 angstrom, circular and square notches of diameters 150 angstrom 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.

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