A Finite-Temperature Continuum Theory Based on Interatomic Potentials

2005 ◽  
Vol 127 (4) ◽  
pp. 408-416 ◽  
Author(s):  
H. Jiang ◽  
Y. Huang ◽  
K. C. Hwang
Keyword(s):  
Temperature Dependence ◽  
Finite Temperature ◽  
Interatomic Potential ◽  
Coefficient Of Thermal Expansion ◽  
Harmonic Approximation ◽  
Continuum Theory ◽  
Single Wall Carbon Nanotubes ◽  
Interatomic Potentials ◽  
Atomistic Models ◽  
Continuum Theories

There are significant efforts to develop continuum theories based on atomistic models. These atomistic-based continuum theories are limited to zero temperature (T=0K). We have developed a finite-temperature continuum theory based on interatomic potentials. The effect of finite temperature is accounted for via the local harmonic approximation, which relates the entropy to the vibration frequencies of the system, and the latter are determined from the interatomic potential. The focus of this theory is to establish the continuum constitutive model in terms of the interatomic potential and temperature. We have studied the temperature dependence of specific heat and coefficient of thermal expansion of graphene and diamond, and have found good agreements with the experimental data without any parameter fitting. We have also studied the temperature dependence of Young’s modulus and bifurcation strain of single-wall carbon nanotubes.

Mechanics of Carbon Nanotubes: A Continuum Theory Based on Interatomic Potentials

2007 ◽  
Vol 340-341 ◽  
pp. 11-20 ◽  
Author(s):  
Han Qing Jiang ◽  
Keh Chih Hwang ◽  
Young Huang
Keyword(s):  
Carbon Nanotubes ◽  
Interatomic Potential ◽  
Coefficient Of Thermal Expansion ◽  
Constitutive Models ◽  
Continuum Theory ◽  
Mechanical Deformation ◽  
Deformation Energy ◽  
Interatomic Potentials ◽  
Linear Elastic ◽  
Defect Nucleation

It is commonly believed that continuum mechanics theories may not be applied at the nanoscale due to the discrete nature of atoms. We developed a nanoscale continuum theory based on interatomic potentials for nanostructured materials. The interatomic potential is directly incorporated into the continuum theory through the constitutive models. The nanoscale continuum theory is then applied to study the mechanical deformation and thermal properties of carbon nanotubes, including (1) pre-deformation energy; (2) linear elastic modulus; (3) fracture nucleation; (4) defect nucleation; (5) electrical property change due to mechanical deformation; (6) specific heat; and (7) coefficient of thermal expansion. The nanoscale continuum theory agrees very well with the experiments and atomistic simulations without any parameter fitting, and therefore has the potential to be utilized to complex nanoscale material systems (e.g., nanocomposites) and devices (e.g., nanoelectronics).

Fracture Nucleation in Single-Wall Carbon Nanotubes Under Tension: A Continuum Analysis Incorporating Interatomic Potentials

2002 ◽  
Vol 69 (4) ◽  
pp. 454-458 ◽  
Author(s):  
P. Zhang ◽  
Y. Huang ◽  
H. Gao ◽  
K. C. Hwang
Keyword(s):  
Carbon Nanotubes ◽  
Continuum Theory ◽  
Single Wall Carbon Nanotubes ◽  
Great Promise ◽  
Interatomic Potentials ◽  
Bifurcation Instability ◽  
Continuum Analysis ◽  
Set Up ◽  
Walled Carbon Nanotubes ◽  
Fracture Nucleation

Carbon nanotubes show great promise for applications ranging from nanocomposites, nanoelectronic components, nanosensors, to nanoscale mechanical probes. These materials exhibit very attractive mechanical properties with extraordinarily high stiffness and strength, and are of great interest to researchers from both atomistic and continuum points of view. In this paper, we intend to develop a continuum theory of fracture nucleation in single-walled carbon nanotubes by incorporating interatomic potentials between carbon atoms into a continuum constitutive model for the nanotube wall. In this theory, the fracture nucleation is viewed as a bifurcation instability of a homogeneously deformed nanotube at a critical strain. An eigenvalue problem is set up to determine the onset of fracture, with results in good agreement with those from atomistic studies.

Temperature dependence of the Raman spectra of single-wall carbon nanotubes

2000 ◽  
Vol 76 (15) ◽  
pp. 2053-2055 ◽  
Author(s):  
H. D. Li ◽  
K. T. Yue ◽  
Z. L. Lian ◽  
Y. Zhan ◽  
L. X. Zhou ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Dependence ◽  
Raman Spectra ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon

TEMPERATURE DEPENDENCE OF ELECTRICAL RESISTANCE OF INDIVIDUAL CARBON NANOTUBES AND CARBON NANOTUBES NETWORK

2012 ◽  
Vol 26 (21) ◽  
pp. 1250136 ◽  
Author(s):  
SAJJAD DEHGHANI ◽  
MOHAMMAD KAZEM MORAVVEJ-FARSHI ◽  
MOHAMMAD HOSSEIN SHEIKHI
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Dependence ◽  
Electric Fields ◽  
Electrical Resistance ◽  
Electrode Materials ◽  
Effect Of Temperature ◽  
Electrode Spacing ◽  
Single Wall Carbon Nanotubes ◽  
Tube Metal

We present a model to understand the effect of temperature on the electrical resistance of individual semiconducting single wall carbon nanotubes (s-SWCNTs) of various diameters under various electric fields. The temperature dependence of the resistance of s-SWCNTs and metallic SWCNTs (m-SWCNTs) are compared. These results help us to understand the temperature dependence of the resistance of SWCNTs network. We experimentally examine the temperature dependence of the resistance of random networks of SWCNTs, prepared by dispersing CNTs in ethanol and drop-casting the solution on prefabricated metallic electrodes. Examining various samples with different electrode materials and spacings, we find that the dominant resistance in determination of the temperature dependence of resistance of the network is the resistance of individual tubes, rather than the tube–tube resistance or tube–metal contact resistance. It is also found that the tube–tube resistance depends on the electrode spacing and it is more important for larger electrode spacings. By applying high electric field to burn the all-metallic paths of the SWCNTs network, the temperature dependence of the resistance of s-SWCNTs is also examined. We also investigate the effect of acid treatment of CNTs on the temperature dependence of the resistance of SWCNTs and also multi-wall CNTs (MWCNTs) networks.

Prediction of site occupancy of C15 Laves phase at finite temperature based on quasi-harmonic approximation model

2018 ◽  
Vol 96 ◽  
pp. 33-40 ◽  
Author(s):  
Zhenyi Wei ◽  
Yixu Yang ◽  
Jinchang Huang ◽  
Bo Wu ◽  
Baisheng Sa ◽  
...  
Keyword(s):  
Finite Temperature ◽  
Harmonic Approximation ◽  
Site Occupancy ◽  
Laves Phase ◽  
Approximation Model

Origin of ferroelectric phase transition in SbSClxI1-x mixed crystals

2014 ◽  
Vol 28 (30) ◽  
pp. 1450209 ◽  
Author(s):  
A. Audzijonis ◽  
L. Žigas ◽  
R. Sereika ◽  
R. Žaltauskas
Keyword(s):  
Phase Transition ◽  
Free Energy ◽  
Temperature Dependence ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Harmonic Approximation ◽  
Temperature Dependent ◽  
Normal Coordinate ◽  
Unit Cell Parameters ◽  
Cell Parameters

The measurements of SbSCl x I 1-x(x = 0.2) temperature dependent capacitance were carried out. The temperature of ferroelectric phase transition TC ≈340 K was measured experimentally. TC of SbSCl x I 1-x was calculated theoretically in anharmonic and harmonic approximations. TC was calculated in anharmonic approximation using temperature dependence of mean potential energy of Sb atoms as a function of the soft B1u symmetry normal coordinate along c(z)-axis. Moreover, TC was calculated in harmonic approximation using temperature dependence of vibrational thermodynamic functions (Helmholc free energy). TC dependence from unit cell parameters a, b and from mixture composition x was carried out.

Sign in / Sign up

Export Citation Format

Share Document