The structural-acoustic energy finite-element method and energy boundary-element method.

摘要

It is important to identify vibrational energy noise paths to reduce the sound field in complicated engineering systems, such as aircraft and automobiles. However, there is no easy method to model the behavior of real plates and acoustic enclosures at high frequencies. A method called Energy Flow Analysis has been developed to predict the structural responses in homogenous systems such as rods, beams, plates, and acoustic spaces. Additional procedures have been built on these results to predict the responses in coupled systems consisting of rods, beams, and plates. In this research, a structural-acoustic coupling relationship is proposed for energy flow analysis of plates and acoustical spaces. The coupling relationship is derived in terms of plate radiation efficiency. Analytical expressions for radiation efficiency of simple models are readily available in the literature as a function of frequency, geometry, and material properties.;The structural-acoustic coupling relationship was implemented into an energy finite element model. The energy finite element method coupling relationship has the capability to implement several discrete values of radiation efficiencies across a radiating plate if the need arises. Energy Flow Analysis is a method to describe sound radiation and to be able to model and predict the structural-acoustic energy levels. Experimental results of a coupled structural-acoustic system were measured and compared to the energy finite element method as a verification study of the proposed coupling relationship. The structural-acoustic coupling relationship was also formulated for an energy boundary element model. A sensitivity analysis method was also formulated and implemented for the energy finite element method.