This paper aims to study the effect of externally applied longitudinal magnetic field on the transverse vibration of viscoelastic double-walled carbon nanotubes （visco-DWCNTs） embedded in a viscoelastic medium. The ...This paper aims to study the effect of externally applied longitudinal magnetic field on the transverse vibration of viscoelastic double-walled carbon nanotubes （visco-DWCNTs） embedded in a viscoelastic medium. The analyses are carried out based on the nonlocal viscoelastic model and Euler-Bernoulli beam theory. Governing equations are derived for the vibration of the embedded visco-DWCNT subjected to a magnetic field, where the Lorentz magnetic force, the surrounding viscoelastic medium, the intertube van der Waals forces and viscoelasticity of the DWCNT are taken into consideration. In this study, the transfer function method is employed to solve the governing equations, which enables one to obtain the natural frequencies and the corresponding mode shapes in closed form for the DWCNTs with arbitrary boundary conditions. Here the developed mechanics model is first compared with the existing techniques available in the literature in a few particular cases, where excellent agreement is achieved. The validation of the model is followed by a detailed parametric study of the effects of longitudinal magnetic field, nonlocal parameter, boundary conditions, structural damping coefficient and aspect ratio of the DWCNTs on their vibration. The study demonstrates the efficiency of the present technique designed for vibration analysis of a complicated multi-physics system comprising DWCNTs, the viscoelastic medium and a magnetic field in longitudinal direction.展开更多
This study introduces a continuum medium approximation(CMA)and an empirical effective medium approxi-mation(EMA)-type formulation to estimate the transport properties,including electrical conductivity,thermal conducti...This study introduces a continuum medium approximation(CMA)and an empirical effective medium approxi-mation(EMA)-type formulation to estimate the transport properties,including electrical conductivity,thermal conductivity,Seebeck coefficient,and Hall mobility,of nanostructured composites.The CMA incorporates the interface parameters mediated by newly introduced distribution functions to resolve predictions that deviate from the inclusion properties at its volume fraction of 1 in current EMAs and yields predictions agreed well with both the empirical EMA and experimental data.The empirical EMA-type formulation resolves the differ-ences in CMA predictions for the media A_(1-x)B_(x)and B_(1-x)A_(x)and provides a unique prediction that agrees very well with experimental data at a given volume fraction ranging from 0 to 1.The effects of the interface param-eters on the transport properties were investigated.The results indicated that the efficiency of nanostructured composites could be further improved by optimizing the interface parameters.展开更多
The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes wi...The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes with the mobilized state of stress along the slope surface is employed by imposing the orientation of principal stresses on the equilibrium equations. Comparisons were made with calculations based on the finite element method using an elastic model. Moreover, experiments on sand heaps deposited on a rectangular rigid base were conducted to validate the theoretical study. The measured pressure profile generally agreed well with theoretical results.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.11272348 and 11302254)
文摘This paper aims to study the effect of externally applied longitudinal magnetic field on the transverse vibration of viscoelastic double-walled carbon nanotubes （visco-DWCNTs） embedded in a viscoelastic medium. The analyses are carried out based on the nonlocal viscoelastic model and Euler-Bernoulli beam theory. Governing equations are derived for the vibration of the embedded visco-DWCNT subjected to a magnetic field, where the Lorentz magnetic force, the surrounding viscoelastic medium, the intertube van der Waals forces and viscoelasticity of the DWCNT are taken into consideration. In this study, the transfer function method is employed to solve the governing equations, which enables one to obtain the natural frequencies and the corresponding mode shapes in closed form for the DWCNTs with arbitrary boundary conditions. Here the developed mechanics model is first compared with the existing techniques available in the literature in a few particular cases, where excellent agreement is achieved. The validation of the model is followed by a detailed parametric study of the effects of longitudinal magnetic field, nonlocal parameter, boundary conditions, structural damping coefficient and aspect ratio of the DWCNTs on their vibration. The study demonstrates the efficiency of the present technique designed for vibration analysis of a complicated multi-physics system comprising DWCNTs, the viscoelastic medium and a magnetic field in longitudinal direction.
文摘This study introduces a continuum medium approximation(CMA)and an empirical effective medium approxi-mation(EMA)-type formulation to estimate the transport properties,including electrical conductivity,thermal conductivity,Seebeck coefficient,and Hall mobility,of nanostructured composites.The CMA incorporates the interface parameters mediated by newly introduced distribution functions to resolve predictions that deviate from the inclusion properties at its volume fraction of 1 in current EMAs and yields predictions agreed well with both the empirical EMA and experimental data.The empirical EMA-type formulation resolves the differ-ences in CMA predictions for the media A_(1-x)B_(x)and B_(1-x)A_(x)and provides a unique prediction that agrees very well with experimental data at a given volume fraction ranging from 0 to 1.The effects of the interface param-eters on the transport properties were investigated.The results indicated that the efficiency of nanostructured composites could be further improved by optimizing the interface parameters.
基金supported by KAKENHI Grant Numbers 23760441 and 24360193The authors would like to expresstheir gratitude to Japan Society for the Promotion of Science(JSPS)
文摘The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes with the mobilized state of stress along the slope surface is employed by imposing the orientation of principal stresses on the equilibrium equations. Comparisons were made with calculations based on the finite element method using an elastic model. Moreover, experiments on sand heaps deposited on a rectangular rigid base were conducted to validate the theoretical study. The measured pressure profile generally agreed well with theoretical results.
