VIBRATION AND SOUND ENERGY FLOW IN THREE-DIMENSIONAL BOX-LIKE STRUCTURES

GOPAL PRASAD MATHUR, Purdue University

Abstract

An analytical model based on Statistical Energy Analysis was developed for predicting the vibration and sound pressure levels inside a three-dimensional box structure due to wide-band random excitation applied at a prescribed point on the structure. The acoustic absorption of the walls of the reverberant enclosure was determined using the theory of room acoustics and incorporated in the theoretical model. The structural damping of the panels which constitute the box structure was experimentally obtained employing the steady state input power method. Theoretical expressions based on mobility concepts were developed and examined for characterizing and estimating the mechanical input power. The effect of variation in the location of the mechanical input on input mobility, input power and sound radiation by a finite structure was studied. The vibration of the panels and noise levels inside the box structure for five different cases of the input mobility characteristics were predicted using the theoretical model and compared with experimental results. The effect of increasing the structural damping on the overall response of the structure was studied. An explicit relationship between input mobility, input power and the panel vibration and noise levels in the box structure was established. On the basis of these results, possible ways of reducing the structure-borne noise radiated into the box structure cavity are suggested.

Degree

Ph.D.

Subject Area

Mechanical engineering

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