STRUCTURAL-ACOUSTIC RESPONSE, NOISE TRANSMISSION LOSSES AND INTERIOR NOISE LEVELS OF AN AIRCRAFT FUSELAGE EXCITED BY RANDOM PRESSURE FIELDS
Abstract
A theoretical and empirical study of the structural-acoustic response and sound transmission properties of fuselage structures is described. The external fluctuating pressure environments discussed are boundary layer turbulence, jet noise and reverberant acoustic fields. In order to investigate the complete behavior of the fuselage, equivalent structural models are analyzed whose combined characteristics represent the complex fuselage structure throughout the entire frequency response range of interest. The structure and interior sound field are treated throughout as a coupled dynamic system whose response is describable in terms of the system's normal modes. Prediction methods are developed for structural responses, noise reduction and internal acoustic fields of untreated and acoustically treated fuselage structures. The results of this study have been programmed for computer solution, thus allowing the significant parameters affecting sound transmission to be determined. In addition to the computer programs, empirical design charts are presented for carrying out pre-design estimates of the external fluctuating loads due to boundary layer turbulence and jet noise and overall noise reduction of typical acoustic treatments.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1968
- Accession Number
- AD0841155
Entities
People
- Alex C. Jolly
- James A. Cockburn