Based on molecular force fields,a new finite element model is constructed for multi-walled carbon nanotubes where the interlayer interactions and C--C bonds are simulated by the elements of piece-wise linear spring an...Based on molecular force fields,a new finite element model is constructed for multi-walled carbon nanotubes where the interlayer interactions and C--C bonds are simulated by the elements of piece-wise linear spring and rectangular cross section beam,respectively.For high computation efficiency and atomic reification,the radial breathing modes of multi-walled carbon nanotubes are studied systemically using this model.The results show the correspondence between carbon nanotube structures and vibrational modes,which provide unequivocal data for the experimental characterization of carbon nanotubes.An empirical relationship of radial breathing modes frequencies with the nanotube radius are also obtained for two-layer carbon nanotubes.展开更多
This paper studies the dynamic shell buckling behavior of multi-walled carbon nanotubes(MWNTs) embedded in an elastic medium under step axial load based on continuum mechanics model.It is shown that,for occurrence of ...This paper studies the dynamic shell buckling behavior of multi-walled carbon nanotubes(MWNTs) embedded in an elastic medium under step axial load based on continuum mechanics model.It is shown that,for occurrence of dynamic shell buckling of MWNTs or MWNTs embedded in an elastic medium,the buckling stress is higher than the critical buckling stress of the corresponding static shell buckling under otherwise identical conditions.Detailed results are demonstrated for dynamic shell buckling of individual double-walled carbon nanotubes(DWNTs) or DWNTs embedded in an elastic medium.A phenomenon is shown that DWNTs or embedded DWNTs in dynamic shell buckling are prone to axisymmetric buckling rather than non-axisymmetric buckling.Numerical results also indicate that the axial buckling form shifts from the lower buckling mode to the higher buckling mode with increasing buckling stress,but the buckling mode is invariable for a certain domain of buckling stress.Further,an approximate analytic formula is presented for the buckling stress and the associated buckling wavelength for dynamic axisymmetric buckling of embedded DWNTs.The effect of radii is also examined.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.10732040)the Natural Science Foundation of Jiangsu Province (Grant No.BK2010501)the Nanjing University of Aeronautics and Astronautics Research Funding (Grant Nos.4015-909322,NS2010220)
文摘Based on molecular force fields,a new finite element model is constructed for multi-walled carbon nanotubes where the interlayer interactions and C--C bonds are simulated by the elements of piece-wise linear spring and rectangular cross section beam,respectively.For high computation efficiency and atomic reification,the radial breathing modes of multi-walled carbon nanotubes are studied systemically using this model.The results show the correspondence between carbon nanotube structures and vibrational modes,which provide unequivocal data for the experimental characterization of carbon nanotubes.An empirical relationship of radial breathing modes frequencies with the nanotube radius are also obtained for two-layer carbon nanotubes.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11172304,11202210,11021262 and 10972010)the National Basic Research Program of China (Grant No. 2012CB937500)
文摘This paper studies the dynamic shell buckling behavior of multi-walled carbon nanotubes(MWNTs) embedded in an elastic medium under step axial load based on continuum mechanics model.It is shown that,for occurrence of dynamic shell buckling of MWNTs or MWNTs embedded in an elastic medium,the buckling stress is higher than the critical buckling stress of the corresponding static shell buckling under otherwise identical conditions.Detailed results are demonstrated for dynamic shell buckling of individual double-walled carbon nanotubes(DWNTs) or DWNTs embedded in an elastic medium.A phenomenon is shown that DWNTs or embedded DWNTs in dynamic shell buckling are prone to axisymmetric buckling rather than non-axisymmetric buckling.Numerical results also indicate that the axial buckling form shifts from the lower buckling mode to the higher buckling mode with increasing buckling stress,but the buckling mode is invariable for a certain domain of buckling stress.Further,an approximate analytic formula is presented for the buckling stress and the associated buckling wavelength for dynamic axisymmetric buckling of embedded DWNTs.The effect of radii is also examined.
