| Acoustics has gained a lot of interest as an important research area in the last half of a century. A number of research centers and institutions are currently conducting research in this field including architectural, structural, aero-, thermo-, underwater, atmospheric, and environmental acoustics, besides several other areas in that field.; Beams, plates and shells are the main elements used in the design of most engineering structures which are normally subjected to mechanical vibrations of some kind. Noise, which results from such vibrations, is the undesired radiated sound which is a concern and must be considered in engineering design. Noise control has therefore become an integral part of the engineering design process. Engineers, therefore, are faced with the task of developing ways of minimizing noise levels, which is commonly referred to as noise control. Applications are in the field of industrial machinery and equipment, aeronautic vehicles, and air conditioning systems among others. In most cases, satisfactory analytical approximations to acoustic radiation are obtained through the Rayleigh integral and boundary integral methods, the former being computationally expensive.; This dissertation is one such endeavor in the area of structural acoustics. It depicts direct analytical methods of approximating the acoustic radiation from linearly varying vibrating circular plates. Previous studies by other authors mainly focused on uniform plates with different geometry and boundary conditions. This study looks into circular plates with linear variation in the radial direction. The l approach lays emphasis on the development and solution of the governing equation of motion of the vibrating plates. The Rayleigh surface integral and the series or surface integration methods are used to approximate the acoustic radiation from the surfaces which are planar or nearly planar.; In the far-field approach, the investigation focuses on the variation of acoustic intensity with the polar angle, the acoustic radiation with frequency for both free and forced vibration, and the radiation efficiency. The series method is employed in the analysis of the latter two cases. Comparison of the analyses is made between aluminum and steel plates. |
