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.