carbon nanotubes

Phys. Rev. B 78, 155436 (2008)   J.Y. Huang, F. Ding, B.I. Yakobson

I would like to invite everyone attending the 2008 ASME IMECE next week in Boston to attend a keynote lecture given by Prof. Ted Belytschko of Northwestern University.  The lecture will occur at 1:45 PM on Tuesday, November 4, and will be entitled "Multiscale Computations of Fracture - When Does Flaw Tolerance Occur?" 

Further information on Prof. Belytschko's talk can be found here: 

http://www.asmeconferences.org/Congress08/PlenarySessions.cfm

Physical Review Letters (Vol.101, No.17):175501

Highlighted by Nature, 465, 5 

Highlighted by Nature Nanotechnology, 31 Oct 2008

Highlighted by NatureChina, 5 Nov 2008

For more than 15 years, carbon nanotubes (CNTs) have been the flagship material of nanotechnology. Researchers have conceived applications for nanotubes ranging from microelectronic devices to cancer therapy. Their atomic structure should, in theory, give them mechanical and electrical properties far superior to most common materials.  

Carbon nanotubes as strong fibers in CNT-composites are subjected to large deformations in radial direction. They provide strength as well as structural damping in the composite. Despite being strong in the axial direction, CNTs are rather soft in the radial direction.

I. Arias and M. Arroyo, Size-Dependent Nonlinear Elastic Scaling of Multiwalled Carbon Nanotubes, Phys. Rev. Lett. 100, 085503 (2008).

PRL 99, 175503 (2007);   Jianyu Huang, Feng Ding, Kun Jiao, Boris I Yakobson

Youtube Movie:  http://www.youtube.com/watch?v=NSNlE8AreeM    http://www.nature.com/nnano/reshigh/2007/1107/full/nnano.2007.404.html

Huang, Nano Lett. 7, 2335 (2007); Philip Ball, Nature 448, 396 (2007)
Watch movies at: http://pubs3.acs.org/acs/journals/supporting_information.page?in_manuscr...  

Huang et al., PRL 98, 185501 (2007)

Watch movies at: http://netserver.aip.org/cgi-bin/epaps?ID=E-PRLTAO-98-002719

We report exceptional ductile behavior in individual double-walled and triple-walled carbon nanotubes at temperatures above 2000 C, with tensile elongation of 190% and diameter reduction of 90%, during in situ tensile-loading experiments conducted inside a high-resolution transmission electron microscope. Concurrent atomic-scale microstructure observations reveal that the superelongation is attributed to a high temperature creep deformation mechanism mediated by atom or vacancy diffusion, dislocation climb, and kink motion at high temperatures. The superelongation in double-walled and triple-walled carbon nanotubes, the creep deformation mechanism, and dislocation climb in carbon nanotubes are reported here for the first time.

This paper has been published in Journal of the Mechanics and Physics of Solids 56 (2008), pp. 1609-1623 (doi:10.1016/j.jmps.2007.07.013).

Abstract

Appl Phys Lett, 90, 201910, 2007

(J Appl Phys, 100, 114327, 2006) 

(PRB,74,245428,2006)  Based on a molecular mechanics concept, a nonlinear stick-spiral model is developed to investigate the mechanical behavior of single walled carbon nanotubes (SWCNTs). The model is capable of predicting not only the initial elastic properties (e.g., Young’s modulus) but also the stress-strain relations of a SWCNT under axial, radial, and torsion conditions. The elastic properties, ultimate stress, and failure strain under various loading conditions are discussed and special attentions have been paid to the effects of the tube chirality and tube size. Some unique mechanical behaviors of chiral SWCNTs, such as axial strain-induced torsion, circumferential strain-induced torsion, and shear strain-induced extension are also studied. The predicted results from the present model are in good agreement with existing data, but very little computational cost is needed to yield them.

Phys. Rev. Lett. 97, 075501 (2006)