Acoustic Radiation from Fluid-Loaded, Ribbed Cylindrical Shells Excited by Different Types of Concentrated Mechanical Drives
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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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 mathematical model includes the effects of fluid loading, internal damping and interactions between ribs. Comparisons of predictions for the shell with a large radius are made to published results for unsupported and line-supported flat plates. 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. Mathematical prediction 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.