An analysis of band gap characteristics of metamaterial plates with dual helix cells

Wide band gaps with the propagation of elastic waves at low-frequency are desirable for phononic crystals in many traditional and novel applications. Inspired by the natural helix, we designed a microstructure in a metamaterial plate with an antisymmetric dual helix as the basic local resonant cell. The band structure and displacement transmission curve of metamaterial plates with dual helix cells were calculated by using the finite element method at first, then the band gap characteristics with and without consideration of the mass in the center of the dual helix were compared. The results show that the band gap in the band structure and displacement transmission curves have excellent consistency. Besides, the effects of the parameters including the number of turns of the helix, the plate thickness, and the radius of the attached mass sphere on the band gaps of flexural waves for the metamaterial plate were examined for further evaluation of the potential vibration prohibition application. It is found that the lower frequency of the band gap can be significantly tuned by adding a mass element in the metamaterial plates with dual helix elements, which provides a new method to tune the width of the band gap of a metamaterial plate.