Exploring bandgap generation mechanism of phonon crystal

In this paper, based on the theoretical research of structural modal analysis, different types of phonon crystal modal structures are designed for the first time, and the characteristics and the generation mechanism of the bandgap were studied through theoretical calculations and experiments. According to the phenomenon in the experimental results, we can find that the vibration transmission characteristics of phonon crystal structure α 3 are the best, and it is also superior to that of phonon crystal structure α 10 (full period structure). Therefore, the comparison of theoretical analysis with experimental phenomena shows that the bandgap generation mechanism should be modal resonance instead of local resonance in the finite periodic structure. The profound reason lies in there is no separate Z direction local vibration mode of periodic structure in the vibration mode of finite structure, and the bandgap of finite structure is the mode superposition torsional resonance mechanism between scatterer and substrate mode.