Statistical Power Flow Analysis of an Imperfect Ribbed Cylinder

✍ Scribed by M. Blakemore; J. Woodhouse; D.J.W. Hardie

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 218 KB
• Volume: 222
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1998.2111

✦ Synopsis

Prediction of the noise transmitted from machinery and ¯ow sources on a submarine to the sonar arrays poses a complex problem. Vibrations in the pressure hull provide the main transmission mechanism. The pressure hull is characterised by a very large number of modes over the frequency range of interest (at least 100,000) and by high modal overlap, both of which place its analysis beyond the scope of ®nite element or boundary element methods. A method for calculating the transmission is presented, which is broadly based on Statistical Energy Analysis, but extended in two important ways: (1) a novel subsystem breakdown which exploits the particular geometry of a submarine pressure hull; (2) explicit modelling of energy density variation within a subsystem due to damping. The method takes account of ¯uid±structure interaction, the underlying pass/stop band characteristics resulting from the near-periodicity of the pressure hull construction, the eect of vibration isolators such as bulkheads, and the cumulative eect of irregularities (e.g., attachments and penetrations).