管内流体对单壁碳纳米管中弯曲波频散的影响

Flexural Wave Dispersion in Single walled Carbon Nanotube Filled with Fluids

由于其管状结构,碳纳米管在纳机械系统中可望被用作输流管道。采用连续介质力学方法,研究管内有流体存在时碳纳米管中弯曲波的传播和频散。建立流体存在时考虑二阶应变梯度的非局部弹性Timoshenko梁方程。流体的存在,使相速度最低的解支相速度降低。当流速较低时,流速对碳纳米管中弯曲波传播的影响不大。当流速较高时,相速度最低的一支随流速增加相速度降低。当流速非常高时,该解支会消失。但流体的存在对其他解支影响不大。随着波数的升高,非局部弹性所描述的微结构对碳纳米管中弯曲波传播的影响越来越明显。

Carbon nanotubes show great potential for use in nanofluidic devices. A nonlocal elastic Timoshenko beam model with second order of strain gradient taken into consideration was established and the corresponding dispersion relation of flexural wave was derived. The velocity of flexural wave of lowest branch in carbon nanotube was found to be lowered by the flow. The phase velocity of flexural wave of lowest branch decreases with increasing flow velocity. The effects of flow velocity on another branches of the dispersion of carbon nanotube can be neglected. The effect of microstructure characteristic by nonlocal elasticity on the dispersion of flexural wave becomes more and more remarkable with increasing wave number.