The Effects of attached Discrete Patches and Point Masses on Eigen Values and Sound Radiation of a Rectangular Plate

Abstract

In the present work, free vibration and sound power radiation response of a simply supported rectangular plate with attached discrete masses and discrete patches have been analyzed using Finite Element (FE) method. The effects of location of attached discrete patches and point masses are investigated for different cases keeping the mass of the (plate + patches) and (plate + point masses) constant. Further, the effect of increasing mass of single attached discrete patch/mass on Eigenvalue is also investigated by FEM using ANSYS as a tool. It has been shown that discrete point masses affect the Eigenvalues more significantly in comparison to attached patches and the mode modification of the plate is possible by attaching patches at certain location. The non-dimensional Eigenvalues of a simply supported rectangular isotropic plate without attached discrete patches/point masses analysed by Wong (J Sound Vib 252:577–583, 3) is also considered for the validation and comparison of natural frequency while that analysed by Li (Appl Acoust 69:272–279, 14) is considered for validation and comparison of sound power level. The maximum sound power radiation of plate with attached discrete point mass is slightly higher than that of the plate with attached patch at the first peak. However, patch contributes significantly in shifting of the frequency at which maximum sound power level occurs. Further, patch is more significant in attaining the minimum sound power level in comparison to that of unloaded plate and plate attached to point masses in the frequency range of 350–550 Hz.