Papers by Author: Fan Yan Meng

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Authors: Fan Yan Meng, Gui Sheng Wang, San Qiang Shi, Shigenobu Ogata
Abstract: We have developed a theoretical method to obtain a single-walled carbon nanotube (SWCNT) with a high density of topological defects. Carbon nanotubes (CNTs) sustain elastic elongation up to 15-30% at low temperature because of the sufficiently high barrier of bond rotations. A large number of topological defects are activated simultaneously and widely distributed over the entire tube wall after heating the stretched tube to an elevated temperature. This is driven by the internal energy of the strained carbon nanotubes. The manner in which topological defects are distributed is affected by the initial strain and the heating temperature. Nanotubes with a large number of topological defects achieve the elongation without breaking.
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Authors: D. Li, Fan Yan Meng, X.Q. Ma, Z. Wang, L.J. Qiao, W.Y. Chu
Abstract: Pipeline steel in soil containing water could induce a macro tensile stress, leading to stress corrosion cracking (SCC). Anisotropic corrosion-induced stress of Fe single crystal is studied by molecular dynamics (MD) in this paper. The surface perpendicular to the z direction is subjected to the corrosion, and the process of corrosion along three crystallographic directions is simulated using MD approach. When the surface with one specific orientation is corroded, two cases are considered: one is that the periodic boundary condition is applied along the x direction, while free boundary condition along the y direction; and the other is that the periodic boundary condition along the y direction, while free boundary condition along the x direction. The results show that both the deflection of the free end and the macro tensile stress of the crystal for the corrosion in three crystallographic orientations are increasing with the increase of the relative depth of the porous layer. The values of the deflection and the macro tensile stress for the two cases depend on the orientation with the free boundary condition when the surface with one specific orientation is corroded. Moreover, the smaller the interplanar spacing along the orientation with the free boundary condition is, the larger the deflection and the macro tensile stress are.
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Authors: D. Li, Fan Yan Meng, X.Q. Ma, Lie Jie Qiao, W.Y. Chu
Abstract: Molecular dynamics (MD) simulation was carried out to investigate the stress distribution and the macro tensile stress for the α-iron single crystal and twin crystal. The results show that there was a maximum tensile stress located at the matrix near the interface between the porous layer and the matrix for the two crystals. It has been found that a steep drop of stress generated at the twin boundary of the twin crystal. The deflection and the macro tensile stress of the single crystal and the twin crystal increased with an increase of the relative depth of the porous layer. The value of the deflection and the macro tensile stress of the single crystal were larger than that for the twin crystal, because there is a steep drop of stress generated at the twin boundary due to the effect of twin interface.
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