Study On Band Gap Characteristics And Impact Properties Of A Three-Dimensional Single-Phase Phononic Crystal With Resonance Element

Three-dimensional locally resonant phononic crystals have the characteristics of elastic band gap in low frequency band and have a far-reaching application prospect in vibration reduction and noise reduction.The traditional three-dimensional locally resonant phononic crystals are limited by the diversity of constituent materials and the complexity of structure,so it is difficult to assemble and manufacture them for practical engineering.Based on this,a novel three-dimensional single-phase locally resonant phononic crystal is proposed to study its acoustic and mechanical properties.Firstly,a novel three-dimensional single-phase phononic crystal structure is proposed,and its irreducible Brillouin region is calculated by Using Bloch theorem.Combined with finite element method,the desired elastic wave value is obtained.COMSOL was used to calculate the band gap structure of standard monocell.It was found that the band gap ratio of standard monocell reached 76.2% in the frequency range of 10000 Hz.Through different band gap modal figure and the lowest elastic wave band gaps directions modal figure study of band gap formation reason,the study found that the unit cell band structure mainly by scatterer and framework and the influence of elastic wave coupling vibration,and through the single cell structure of transmission loss spectrum and single cellular sandwich structure of transmission loss spectrum test and verify the reliability of band structure.Secondly,the influence of material composition and structure geometry on band structure is studied,and the direction of optimizing band gap is discussed.Materials were studied using six different material parameters on the characteristic,the influence of unit cell band gap with a dual unit cell,different studies have shown that a dollar of unit cell material will not affect the form of band structure,dual band structure of the single cell in the low band gap starting frequency,total bandwidth and superior to the one yuan of band gap accounted unit cell;The effects of frame size,scatterer size and single cell size are analyzed.The results show that the scatterer thickness has the greatest influence on the band structure,and the initial frequency of the minimum band gap can be reduced by increasing the scatterer thickness appropriately.Finally,using 3 D printing preparation containing standard unit cell sandwich board specimen,through the impact test to study the impact performance,thickness and unit cell were analyzed by using finite element simulation framework scatterer thickness on the impact properties of sandwich panel,results show that changing the thickness of the frame or by changing the thickness of the scatterer with standard cell sandwich board impact performance is more stable.