ACOUSTIC RADIATION FROM FLUID-LOADED, RIBBED CYLINDRICAL-SHELLS EXCITED BY DIFFERENT TYPES OF CONCENTRATED MECHANICAL DRIVES

Analytic expressions are derived for the far-field acoustic radiation from a fluid-loaded circular cylindrical shell reinforced with two sets of parallel periodic ribs and excited by seven types of mechanical point drives: single radial, in- and out-of-phase double radial, axial moment, circumferential moment, and in- and out-of-phase in-plane double circumferential. The ribs interact with the cylindrical shell only through normal forces. The model includes the effects of fluid loading, internal damping, and interactions between ribs. Measurements of the acoustic radiation from a ribbed cylindrical shell excited by different types of drives are presented. Comparisons between measured and predicted results are made. Predictions of the acoustic radiation from the unsupported and supported shell with different types of drives are compared. The effects of properties of the shell and types of drives on the acoustic radiation are examined by example and some physical interpretation of significant features are offered.