Hsien-Chie Cheng¹, Yu-Chen Hsu², Wen-Hwa Chen²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 73-74, 2009, DOI:10.3970/icces.2009.012.073

Abstract Due to the limitation of fabrication technologies nowadays, initial defects in carbon nanotubes (CNTs) are inevitably perceived particularly during the manufacturing process or chemical treatment. The investigation of the effects of initial defects existing in CNTs on their mechanical properties and fracture behaviors becomes essential for their potentiality in engineering applications.
In this study, the defect effects, including number in percentage, type, and location, are explored using the molecular dynamics (MD) simulation with Tersoff Brenner potential. Results show that the mechanical properties, such as the elastic modulus, failure strength and strain, are strongly affected by the defects. Moreover, the distribution… More >

Hsien-Chie Cheng¹, Chun-Hung Wu², Yang-Lun Liu², Wen-Hwa Chen²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.3, pp. 65-66, 2009, DOI:10.3970/icces.2009.011.065

Abstract This study attempts to explore the thermal effect on the vibrational behaviors of single-walled carbon nanotube (SWCNT) using both a constant temperature molecular dynamics (MD) simulation that incorporates a Nosé-Hoover thermostat and a modified molecular structure mechanics (MMSM) model. The MD simulation is combined with a Nosé-Hoover thermostat, which controls the temperature of the system by an additional thermal reservoir. On the other hand, the MMSM model adopts equivalent beam elements and spring elements to simulate the bonding and non-bonding interactions between atoms, respectively, where the effect of temperatures can be also taken into account through Badger's rules.
The natural… More >

Hanqing Jiang¹, Junqiang Lu², Min-Feng Yu², Yonggang Huang³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 133-144, 2008, DOI:10.3970/icces.2008.006.133

Abstract The periodic lattice registry of multi-walled carbon nanotubes (MWCNTs) have been exploited for the possibilities of development of nanodevices. This paper studied the telescoping behaviors of double-walled carbon nanotubes (DWCNTs) by atomic-scale finite element and tight-bind Green function methods. It was found that telescoping a DWCNT (e.g., (6,3)/(12,6)) will induce a rotational motion of the inner CNT that has a chirl angle θ (0◦ < θ < 30◦). This telescoping-induced rotational motion does not exist for armchair and zigzag DWCNTs due to the symmetry of CNTs. The rotational angle is completely determined by the chirality of the inner CNT and… More >

Larissa Stieven Montagna, Isabela CÉSAR Oyama, Rita de CÁSSIA Barbosa Camargo Lamparelli, Ana Paula Silva, THAÍS Larissa do Amaral Montanheiro, Ana Paula Lemes^*

Journal of Renewable Materials, Vol.7, No.2, pp. 117-128, 2019, DOI:10.32604/jrm.2019.00036

Abstract Biodegradable polymers have been increasingly used for scientific and commercial applications because they are similar to some conventional thermoplastics and exhibit the ability of self-degradation. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanocomposites films with 1 and 2 wt% of carbon nanotubes (CNT) were prepared by solution mixing, followed by solvent evaporation. In this work, PHBV/CNT nanocomposites were submitted to biodegradation in an aqueous medium for 34 days through a respirometric system. Then, the PHBV films were analyzed by the CO2 production and mineralization as a response of a microbial attack, which was monitored by back titration during all the experiment. The films were also… More >

H. T. Wang¹, Z. H. Yao²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 95-96, 2009, DOI:10.3970/icces.2009.009.095

Abstract Carbon nanotubes (CNTs) may provide ultimate enhancement in stiffness and str\discretionary {-}{}{}ength for composite materials. This paper presents a rigid-fiber-based boundary integral equation formulation for the numerical simulation of debonding process and the corresponding strength of CNT reinforced composites. The CNT/matrix interfaces are assumed to fail when the interfacial shear force reaches a prescribed threshold, and the CNTs and matrix are considered to be detached in the failed areas. The matrix with one or several tens of originally well-bonded CNTs is subjected to an incremental tensile load and the effective stress-strain relations are readily obtained by the introduction of CNT/matrix… More >

P. Reena Monica^1,*, V. T. Sreedevi²

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.3, pp. 577-591, 2019, DOI:10.32604/cmes.2019.04718

Abstract A mathematical model and experimental analysis of the impact of oxide thickness on the ambipolar conduction in Schottky Barrier Carbon Nanotubes (CNTs) Field Effect Transistor (SB CNTFETs) is presented. Suppression of ambipolar conduction in SB CNTFETs is imperative in order to establish them as the future of IC technology. The ambipolar nature of SB CNTFETs leads to a great amount of leakage current. Employing a gate oxide dielectric of thickness, t_ox~50 nm suppresses the ambipolar behavior. In an SB CNTFET, it is the electric field at the source/drain contacts that control the conductance and the band bending length at the… More >

L. Nasdala¹, G. Ernst¹, M. Lengnick¹, H. Rothert¹

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.3, pp. 293-304, 2005, DOI:10.3970/cmes.2005.007.293

Abstract Like any other geometric structure or building, carbon nanotubes may break down due to either material failure or structural failure. In this paper, it is shown that the failure mechanism of carbon nanotubes not only depends on the type and direction of loading but also on the location and number of defects. For the finite element simulations we use a new 4-node finite element without rotational degrees of freedom based on the force field method. For the examples shown here, mainly a single-walled (10,10) armchair nanotube with different Stone-Wales defects, the material parameters are directly taken from the DREIDING force… More >

Wanlin Guo^1,2, Huajian Gao²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.1, pp. 19-34, 2005, DOI:10.3970/cmes.2005.007.019

Abstract A systematic investigation is performed on energy dissipation related interaction force associated with interlayer motion of sliding, rotation and telescoping between any two possible neighboring carbon nanotubes. In particular, we analyze the interlayer corrugation energy and sliding, rotation and telescoping resistance force associated with the Lennard-Jones potential as well as a registry-dependent graphitic potential. It is found that the interlayer resistance associated with both of these potentials can vary with the morphology, length and diameter of the two tubes. Energy dissipation related fluctuation of the resistant force can be as low as 10^-18N/atom between the most optimistic tube pairs, but… More >

Liu Yang¹, Jie Han, M. P. Anantram, Richard L. Jaffe

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 675-686, 2002, DOI:10.3970/cmes.2002.003.675

Abstract Bonding geometry and bandgap of carbon nantotubes under uniaxial and torsional deformation are studied computationally for nanotubes of various chiralities and diameters. Bonding geometries are obtained with Tersoff-Brenner potential from molecular mechanics simulations. Bandgaps as function of strain are calculated from the molecular mechanics structures using one (p) and four (2s and 2p_x, 2p_y, 2p_z) orbital tight-binding models. For small strains, the bandgap results are qualitatively consistent with those predicted by the one orbital analytical model. Response of the electronic properties of nanotubes to large strains is characterized by a change in sign of d(bandgap)/d(strain). These originate from either quantum… More >

Jan Badorrek^1,2, Michael Walter^3,4,*, Marie-Pierre Laborie^1,2,*

Journal of Renewable Materials, Vol.6, No.3, pp. 325-335, 2018, DOI:10.7569/JRM.2017.634183

Abstract Doping lignin with carbon nanotubes is a promising strategy for cost-effective high-performance carbon fibers. We investigate the intermolecular interaction potential of CNT and organosolv lignin with two main approaches. Experimentally, oxidized purified multiwalled carbon nanotubes (MWCNTs) and beech organosolv lignins and derivatives are analyzed with their Hansen solubility parameters (HSPs) to assess their mutual compatibility. Theoretically, dispersion-corrected density functional theory simulations of the interaction between model molecules and single-walled carbon nanotubes reveal the source of interactions. We find that oxidation enables and enhances the interaction between carbon nanotubes and organosolv lignin experimentally, which is in agreement with the enhanced polar… More >