磁约束双层夹心悬臂梁的振动分析

采用在约束层端部上设置永磁体的新方法可使阻尼层获得比传统约束阻尼处理方法更高的剪应变，从而增强粘弹层的阻尼耗能，降低共振峰。本文应用Hamilton原理，推导了全覆盖双层约束阻尼悬臂梁的运动方程，对模型进行了实验验证；分析了不同物理和几何参数下该方法的减振效果。研究表明，磁约束能提高阻尼减振效果。随着阻尼层厚度的增加，无磁约束的共振峰降低较少，而有磁约束的共振峰急剧降低，减振效果明显。阻尼层剪切模量G的变化对磁约束减振效果的影响较大；当G小于一定值时，减振效果明显，但当G大于一定值时，减振效果急剧降低。在不同的约束层弹性模量和厚度下，磁约束仍起作用。此外，分析了具有较大控制力的主被动混合磁约束振动控制方法的可行性。

Vibration Analysis of a Magnetic constrained Double Sandwich-Type Cantilever Beam

The shear strains of visoelastic damping layers resulting from the attraction arrangement magnets on the constraining layers root are higher than those of the conventional passive constrained layer damping(PCLD). Therefore, significant improvement of the damping characteristics can be achieved by using magnetic constrained layer damping(MCLD) treatment .In this paper, The differential equations of motion of a fully covered damped sandwich-type cantilever beam are derived employing Hamilton's principle. The model is validated experimentally. The effects of different physical and geometrical parameters on the first resonance amplitude are evaluated. It is shown that improvement of the damping characteristics can be achieved by using MCLD. As the damping layer thickness increases to some extent, the use of the MCLD significantly improves the damping characteristics of conventional PCLD treatments. The interaction between the magnets and the damping layers is sensitive to the damping layer's shear modulus G. Increasing in G decreases the improvement of the MCLD. The use of the MCLD has also effect on the system for different Young's modulus and thickness of the constraining layer .Moreover, It is also shown that passive and active hybrid vibration control of beam with magnetic constrained layer damping can be viable treatment.