纵向磁场激励下简支输流微梁的动力学行为研究

受磁场驱动的微机电系统在工作中存在着力、磁、流-固耦合等非线性特征,其力学行为非常复杂,并将影响系统运行的安全性与可靠性.该文采用非局部Euler梁模型研究磁场激励下简支输流微梁(一种微机电系统)的动力学行为,通过动力系统分支理论和谐波平衡法来考察系统的稳定性和幅频特性曲线.结果表明,可以采用改变磁场强度、流速和阻尼的三重方式调节微机电系统的频率.研究中还发现,小尺度效应和磁场强度可以影响临界流速,阻尼的存在可以改变临界流速的个数和系统的分岔类型.

Dynamical Behavior Analysis of Micro Beams Conveying Fluid in Longitudinal Magnetic Fields

Such nonlinear characteristics as mechanics, magnetics and fluid structure interactions exist in the micro electromechanical system (MEMS) driven by the magnetic field, which will affect the safety and reliability of the system. Based on the nonlocal Eulerian beam model, the dynamical behaviors of fluid conveying micro beams (a kind of MEMS) in magnetic fields were studied. The dynamical system bifurcation theory and the harmonic balance method were used to study the stability and amplitude frequency characteristic curves of the pinned pinned micro beam system. The results show that, the frequency of the beam can be adjusted through changes of the magnetic field intensity, the flow velocity and the system damping. The small scale effects tend to change the critical velocity and the existence of damping can change the number of critical velocities and the type of bifurcation.