夹杂及弹性耦联对手性蜂窝复合材料吸振带隙的影响

为了研究手性蜂窝复合材料的振动特性与其振动传播带隙之间的关系,首先,建立了该种材料离散多自由度的夹杂-韧带振动力学模型,该模型考虑了其内嵌夹杂的局部振动与由微结构韧带连接的节点环之间的弹性耦联及诱发共振模态。然后,重点研究了微结构元件之间的耦联程度和微结构元件的尺寸参数对材料吸振带隙低频段和高频段的影响,并结合有限元方法对模型进行了验证分析。结果表明:除柔性包覆的夹杂以外,耦联诱发振动、节点环和韧带的材料及尺寸参数都对手性蜂窝复合材料的固有振动频率产生显著影响,从而控制带隙的位置和带宽。随着节点环内、外弹性耦联程度的减小,夹杂的模态频率将控制带隙的低频段,且随着夹杂质量的增大,低频段的频率降低;高频段由韧带振动表征;当节点环内、外弹性耦联程度增大时,带隙的低频段对韧带和框架的模态更加敏感,从而出现比夹杂模态频率更低的带隙。无论弹性耦合程度强弱,当韧带和节点环的厚度减小时,材料第三阶较高的包覆层变形频率将被相对更低的韧带振动频率取代。所得结论可为小尺寸、低频宽带隙手性蜂窝型隔振材料的设计研究提供理论指导。

Influence of inclusion and elastic coupling on vibration absorbing band gap of chiral honeycomb composites

In order to investigate the relationship between the vibration characteristics of chiral honeycomb composite with its band gap of vibration propagation, a discrete multi-degree of freedom inclusions-ligament vibration mechanical model of the material was established firstly. The model took elastic coupling between the local vibration of embedded inclusion and node ring connected by micro-structure ligaments as well as the evoked resonant eigenmodes into consideration. Then, the effects of coupling degree between micro-structural components and size parameters of micro-structural components on low frequency zone and high frequency zone of vibration absorbing band gaps of the materials were investigated emphatically, and the model was verified and analyzed by finite element method. The results show that except for flexible coated inclusions, the coupled evoked vibration, material and size parameters of node ring and ligaments all have obvious influences on natural vibration frequencies of chiral honeycomb composites, and thereby control the band gap position and band width. With the inner and outer elastic coupling degree node rings decreasing, the model frequency of inclusion will control the low-frequency zone of brand gap, and with the inclusion mass increasing, the frequency of low-frequency zone decreases. The high-frequency zone is characterized by the vibration of ligaments. When the inner and outer elastic coupling degree of node rings increasing, low-frequency zone of band gap is more sensitive to the eigenmodes of ligaments and framework, thus gap brand whose frequency is lower than that of inclusion eigenmode emerges. Whether the elastic coupling degree is strong or weak, when the thickness of ligament and node ring is reducing, the higher third-order frequency of the deformation of coating layer will be replaced by relatively lower frequency of ligament vibration. The conclusion can provide theoretical guidance for designing and research of chiral honeycomb type vibration isolation materials with small size and low-frequency wide band gap.