The Defect States Of Two-dimensional Phononic Crystals With Electrorheological Material

Since in the late 1950s the American physicist Androws found that the electron’s scattering is disordered by disordered field, then the result is localized. Many people observed this phenomenon in optical wave or acoustic wave. Thus sparked the study of the defect state in phononic crystals.Now many people use the improved PWE method combined with the supercell technique to study the defect state. Some other people choose FDTD method. We find that many conventional two-dimensional phononic crystals have been calculated. In this paper we use a new material—ER material. The systems consist of Epoxy cylinders with circular cross section inside ER material in a 9x9 supercell. We change the voltage, the filling fraction and the defect radius, calculating the two-dimensional Epoxy/ER material phononic crystal’s band structure.First, this paper focuses on the one point defect states of the two-dimensional Epoxy/ER material phononic crystals. Changing the voltage, the filling fraction, the defect radius of this system, then analyzing the band structure. Increasing the voltage can lead to change the frequency of defect states and the band gaps. At the same time when the voltage reaches a certain value, the pressure of the defect states are localized in the defect perfectly. The filling fraction and the defect radius of the defect can also change the frequency of the defect state and band gaps.Second, analyzing the two point defect states of the two-dimensional Epoxy/ER material phononic crystals. Discussing the three models’band structure. Changing the voltage, the filling fraction, the defect radius of this system, then analyzing the band structure. We can find that the band structure of the two nearest defects are much different from the others. So the geometry of the two point defect states is very important to the band structure. The double cavities result in the splitting of the defect levels.Finally, in this paper we study the acoustic waves propagating in the linear and bend defects in two-dimensional Epoxy/ER material phononic crystals. There are 5 types linear defects in this part. By changing the electric field, the filling fraction and the defect radius, then calculating the band structure. Comparing the band structure of the linear defect and the double width linear defect and the others.For the research, we can get the factors that can change the band structure of the two-dimensional Epoxy/ER material phononic crystal, this results can be a guide for the experimental research.