The effect of the driving frequency on the directivity pattern of the stepped circular plate
LAN Zheng-kang , HE Xi-ping* , MA Huan-pei, Abulizi·Abulaiti
(College of Physics and Information Technology,Shaanxi Normal University, Xi′an 710062, Shaanxi, China)
Abstract:
Using the finite element methed, the nodal circular of the stepped circular plate is calculated with different driving frequency. When a nodal circular is smaller than the stepped location, the stepped circular plate is divided into three parts by the location of the nodal circular and the stepped. In this case, a method that analytical calculate the three-part displacement distribution is proposed and this method is verified by finite element method. Then the expression of radiated acoustic pressure is derived by the principle of superposition in the acoustic field, and the effect on the directivity pattern is calculated with different driving frequency. Our results show that the difference between the driving frequency and the frequency of the stepped circular plate will lead the main lobe of the directivity pattern becomes wider. The main lobe of directivity pattern will bifurcate when the driving frequency increases to a certain value, which makes the energy of the radiated acoustic field relatively dispersed
KeyWords:
stepped circular plate; flexural vibration; driving frequency; nodal circular; directivity pattern
