• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.8
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• pp.733-738
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• 2009

Mechanical properties of <001> silicon nanowires are presented. In particular, predictions from the calculations based on different length scales, first principles calculations, atomistic calculations, and continuum nanomechanical theory, are compared for <001> silicon nanowires. There are several elements that determine the mechanics of silicon nanowires, and the complicated balance between these elements is studied. Specifically, the role of the increasing surface effects and reduced dimensionality predicted from theories of different length scales are compared. As a prototype, a Tersoff-based empirical potential has been used to study the mechanical properties of silicon nanowires including the Young's modulus. The results significantly deviates from the first principles predictions as the size of wire is decreased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.127-137
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• 2004

We have investigated the structures, the energetic, and the nanomechanics of the single-wall boron-, aluminum-, and gallium-nitride nanotubes using atomistic simulations based on the Tersoff-type potential. The Tersoff-type potential for the III-nitride materials has effectively described the properties of the III-nitride nanotubes. Nanomechanics of boron-, aluminum-, and gallium-nitride nanotubes under the compression loading has been investigated and their Young's moduli were calculated.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.157-158
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.293-294
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.185-186
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• 2007

• Advances in aircraft and spacecraft science
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• v.5 no.6
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• pp.691-729
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• 2018

In this paper the hygro-thermo-mechanical vibration and buckling behavior of embedded FG nano-plates are investigated. The Eringen's and Gurtin-Murdoch theories are applied to study the small scale and surface effects on frequencies and critical buckling loads. The effective material properties are modeled using Mori-Tanaka homogenization scheme. On the base of RPT and HSDPT plate theories, the Hamilton's principle is employed to derive governing equations. Using iterative and GDQ methods the governing equations are solved and the influence of different parameters on natural frequencies and critical buckling loads are studied.

• Structural Engineering and Mechanics
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• v.68 no.1
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• pp.131-157
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• 2018

In this study, Eringen nonlocal elasticity theory in conjunction with surface elasticity theory is employed to study nonlinear free vibration behavior of FG nano-plate lying on elastic foundation, on the base of Reddy's plate theory. The material distribution is assumed as a power-law function and effective material properties are modeled using Mori-Tanaka homogenization scheme. Hamilton's principle is implemented to derive the governing equations which solved using DQ method. Finally, the effects of different factors on natural frequencies of the nano-plate under hygrothermal situation and various boundary conditions are studied.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.122-128
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• 2013

This paper describes the on-machine surface form evaluation of an ultra-precision cylinder for the fabrication by the compensation process. In this study, the surface form error of an ultra-precision cylinder, which was fabricated by the ultra-precision diamond turning machine with a single diamond cutting tool, was evaluated by using two capacitance-type displacement probes. Based on the measurement results, the compensation process was conducted. Since the measurement was carried out on the machine without re-mounting of the workpiece, additional fabrication for compensation process can be conducted precisely.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.559-562
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• 2004

Carbon nanotube is a geometrical frame-like structure and the primary bonds between two nearest-neighboring atoms act like beam members, whereas an individual atom acts as the joint of the related beam members. The sectional property parameters of these beam members are obtained from molecular mechanics. Computations of the elastic deformation of single-walled carbon nanotubes reveal that the Young's moduli of carbon nanotubes vary with the tube diameter and are affected by their helicity. With increasing tube diameter, the Young's moduli of carbon nanotubes approach the Young's modulus of graphite.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1165-1174
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• 2003

The responses of hypothetical silicon nanotubes under torsion have been investigated using an atomistic simulation based on the Tersoff potential. A torque, proportional to the deformation within Hooke's law, resulted in the ribbon-like flattened shapes and eventually led to a breaking of hypothetical silicon nanotubes. Each shape change of hypothetical silicon nanotubcs corresponded to an abrupt energy change and a singularity in the strain energy curve as a function of the external tangential force, torque, or twisted angle. The dynamics o silicon nanotubes under torsion can be modelled in the continuum elasticity theory.