DEDICATED 3-D ACOUSTIC MULTILAYER RESPONSE MODEL

THE SAFETY OF SUBMARINES REQUIRES THAT THEY BE DESIGNED ACOUSTICALLY QUIET TO AVOID DETECTION. ONE METHOD TO REDUCE ACOUSTIC EMISSION IS TO SURROUND THE HULL WITH A VISCOELASTIC LAYER. IN ORDER TO ACCESS THE EFFECTIVENESS OF THESE VISCOELASTIC LAYERS, IT IS NECESSARYTO DETERMINE THE THREE-DIMENSIONAL (3-D) SURFACE COMPLEX IMPEDANCE AND ACOUSTIC LOSS AS A FUNCTION OF FREQUENCY FOR A STEADY STATE HARMONIC INPUT. THIS PROJECT WILL PROVIDE FOR THE ACCURATE ASSESSMENT OF THE EFFECTIVENESS OF THESE VISCOELASTIC LAYERS BY DEVELOPING AN EFFICIENT, MODULAR, USER-FRIENDLY, DEDICATED 3-D FINITE ELEMENT CODE THAT IS CAPABLE OF DETERMINING THE COMPLEX SURFACE IMPEDENCE AS A FUNCTION OF THE STEADY STATE DRIVING FREQUENCY AND ACCURATE MODELING TECHNIQUES FOR THESE UNIQUE GEOMETRIES.