电流变夹层梁的动力稳定性分析

将电流变液等效为线性粘弹性材料，并假定在小变形情况下其储能模量和损耗因子与加在它上面的电场成正比，利用Hamilton原理和有限元方法建立电流变夹层梁的动力学方程。分析不同外加电场和厚度比情况下，电流变夹层梁的振动特性及动力稳定性。通过对单频轴向激励作用下电流变夹层悬臂梁的仿真计算显示，外加电场的增大能提高电流变夹层梁的刚度和阻尼损耗，减少不稳定区域的大小，而电流变层厚度的增加将使梁的固有频率降低，但提高了梁的稳定范围。表明合理设计电流变夹层梁可以有效抑制振动，提高系统的稳定性。

DYNAMIC STABILITY ANALYSIS OF ELECTRORHEOLOGICAL SANDWICH BEAMS

Assuming electrorheological (ER) fluids behave as linear viscoelastic materials, and their storage modulus and loss factor are dependent on the applied electric fields, equations of motion of sandwich beams with an ER materials layer were derived based on the Hamilton's principle and finite element method (FEM). The influences of different electric fields and thickness ration on the resonant frequencies, modal loss factors and dynamic stability boundaries are presented. The results of numerical simulation for ER cantilever beam under simple resonance excitation show that the increase in the electric field can change the stiffness and model loss factor of the ER sandwich beam and improve the dynamic stability of system, whereas the resonant frequencies of the ER sandwich beam will decrease and the regions of dynamic instability reduce as increasing the thickness ratio of the ER layer. So the ER materials layer can attenuate the vibration and improve the dynamic stability of beams when the parameters of ER sandwich beams are optimized.