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基于非局部理论的黏弹性纳米杆轴向振动与波传播研究.

Authors :
唐光泽
姚林泉
李成
季长剑
Source :
Applied Mathematics & Mechanics (1000-0887). Jan2019, Vol. 40 Issue 1, p36-46. 11p.
Publication Year :
2019

Abstract

The longitudinal dynamics of viscoelastic nanorods was investigated based on the nonlocal theory and the Kelvin viscoelastic theory, including axial free vibration and wave prop⁃ agation. Firstly, the partial differential governing equations were derived and then the 1st 3 vi⁃ bration properties were discussed under 3 kinds of typical boundary conditions with the dimen⁃ sionless method. Finally, the relationships between the circular frequency, the wave speed and the wave number were obtained in the problem of wave propagation. The numerical results show that, the small⁃scale effect makes the 1st and 2nd frequencies decrease persistently and the 3rd frequency increase first and decrease later, which indicates that the nanostructural stiff⁃ ness is weakened or strengthened. In particular, for a concentrated mass at the free end of the nanorod, the 2nd frequency has multiple values when the viscoelastic coefficient increases, which may cause instability. The numerical examples also prove that stronger nonlocal effect brings lower damping effect of viscoelastic materials. The longitudinal wave can propagate at high wave numbers due to occurrence of the escape frequency. The effects of viscoelastic coef⁃ ficients on the damping ratio may be ignored at low wave numbers, however, be significant at high wave numbers. [ABSTRACT FROM AUTHOR]

Details

Language :
Chinese
ISSN :
10000887
Volume :
40
Issue :
1
Database :
Academic Search Index
Journal :
Applied Mathematics & Mechanics (1000-0887)
Publication Type :
Academic Journal
Accession number :
151937821
Full Text :
https://doi.org/10.21656/1000-0887.390166