Size-dependent frequency and stability characteristics of axially moving microbeams based on modified couple stress theory

被引:37
作者
Dehrouyeh-Semnani, Amir Mehdi [1 ,2 ]
Dehrouyeh, Mohammad [3 ]
Zafari-Koloukhi, Hamid [2 ]
Ghamami, Mehdi [4 ]
机构
[1] Univ Tehran, Coll Engn, Sch Mech Engn, Tehran, Iran
[2] Univ Tehran, Coll Engn, Sch Mech Engn, Tehran, Iran
[3] Babol Univ Technol, Dept Civil Engn, Babol Sar, Iran
[4] Isfahan Univ Technol, Dept Mech Engn, Esfahan, Iran
关键词
Axially moving microbeam; Timoshenko beam theory; Natural frequency; Divergence bifurcation; Critical velocity; Modified couple stress theory; FREE-VIBRATION ANALYSIS; LENGTH SCALE PARAMETER; NATURAL FREQUENCIES; NONLINEAR DYNAMICS; BUCKLING ANALYSIS; TIMOSHENKO BEAMS; CRITICAL SPEEDS; SANDWICH BEAM; MODEL; BEHAVIOR;
D O I
10.1016/j.ijengsci.2015.09.003
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
This investigation aims to explore dynamic characteristics of axially moving Timoshenko microbeams by taking into account size-dependency based on a modified couple stress theory. Size-dependent motion equations and associated boundary conditions are established via Hamilton's principle. In addition, size-dependent axially moving Euler-Bernoulli beam model can be recovered from the present Timoshenko beam model by reinstating the normality assumption. Galerkin method is applied to discretize the partial differential equations into a set of ordinary differential equations, and then the size-dependent dynamic characteristics of axially moving microbeams with simply supported and doubly clamped boundary conditions are numerically determined. It is observed that the microbeams losestability via a divergence bifurcation in the first mode. The results illustrate that the critical velocity in which the instability occurs and also the natural frequencies significantly increase when the role of size-dependency is of great importance. Finally, the sensitivity of frequencies to velocity and also the influence of size-dependent shear deformation on frequencies and critical velocities are examined. (C) 2015 Elsevier Ltd. All rights reserved.
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页码:98 / 112
页数:15
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