Field-dependent dynamic properties of magnetorheological elastomer-based sandwich beams
Field-dependent dynamic properties of magnetorheological elastomer-based sandwich beams
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DOI：
10.1117/12.598422
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发表时间：
2005-05
期刊：
影响因子：
--
通讯作者：
G. Zhou;Q. Wang
中科院分区：
文献类型：
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作者：
G. Zhou;Q. Wang
磁流变弹性体（MRE）是一种动态剪切模量随磁场变化的固态智能材料。但其较低的剪切模量（约为0.388MPa）确实阻碍了其应用。夹层结构是一种可供选择的结构形式，因为夹层结构的外层薄蒙皮可以增强结构的整体抗弯刚度，而夹层结构的横向柔度会影响结构的整体抗弯动力性能。本文通过高阶模型，从理论上研究了由导电蒙皮和非导电蒙皮组成的磁流变夹层梁的场相关动力学特性。通过定义的最大场诱导的体积弯曲动态刚度的相对变化作为可控性指标，结构设计，以产生最大的可控性，通过无量纲分析。对简支磁流变夹层梁的数值模拟表明：（1）夹层梁的反共振频率和共振频率随外加磁场的变化而变化，最大可达30%;（2）磁流变夹层梁的体场相关弯曲动力学特性主要取决于磁流变夹层梁芯的剪切模量;（3）在最佳组合点附近，通过减小芯层厚度可以显著提高可控性/质量比;（5）当蒙皮的杨氏模量较低时，蒙皮的归一化密度对可控性的影响较小。研究表明，夹层结构可以很好地利用磁流变弹性体的可控特性，实现适用的变刚度装置。
Magnetorheological elastomer (MRE) is a solid-state smart material with field-dependant dynamic shear modulus. But, its lower shear modulus, which is about 0.388MPa, does prevent its application. Sandwich configuration is an alternative to apply MRE in engineering since the outer thin skins will strengthen the bulk flexural stiffness and the transverse flexibility of the MRE core will affect the bulk flexural dynamic performance. In this paper, the field-dependant dynamic property of MRE-based sandwich beams, composed of conductive skins or non-conductive skins, is addressed theoretically through a high order model. By defining the maximum field-induced relative change of the bulk flexural dynamic stiffness as controllability index, structure designs to yield maximum controllability are presented through a non-dimensional analysis. The simulation on simply supported MRE-based sandwich beam indicates: (1) the anti-resonant frequencies and resonant frequencies of the sandwich beam change with applied magnetic fields up to 30%; (2) the bulk field-dependant flexural dynamic property is mainly depended on the field-dependant shear modulus of the MRE core; and, (3) there is an optimal combination of the thickness of the core and the thickness of the skins for maximum controllability; (4) around the optimal combination point, the controllability/mass ratio can be enhanced dramatically though decreasing the core thickness; (5) the normalized density of the skins affects the controllability slightly when the Young's modulus of the skins is low. This work indicates that sandwich structures can well utilize the controllable property of MRE to realize applicable stiffness changeable devices.