Noureddine Atalla
Dept. of Mech. Eng., Univ. de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
The objective of this presentation is to present a simple but efficient code for the investigation of the effects of structural design modifications on the radiated power of plate-like structures. The code (A.D.N.R.: acoustic design for noise reduction) is based on a variational formulation for the vibration problem that allows it to model easily the effects of typical design modifications such as added stiffeners, added mass, viscoelastic damping, excitation type, and location. To solve the acoustic problem, the approach used in the presented code addresses both the accuracy and computation time problem. It is based on a multipole expansion of Green's kernel. This expansion allows for a quick and rigorous evaluation of the radiation efficiency. Due to its simplicity, the presented approach constitutes a deterministic step towards answering the accuracy versus computation time usually brought up by engineers. In addition, it is a very useful tool for pedagogic purposes in undergraduate and graduate courses since it can be used to show, rapidly, how the radiated acoustic power is modified for various design configurations. During the presentation, the theoretical background of the presented code will be recalled and the effects of typical design modifications on the radiated power will be demonstrated through several examples. Finally, conclusions concerning the advantages and limitations of the presented code will be stated. [Work supported by CRSNG and IRSST, Canada, and INRS, France.]