ACOUSTIC TRANSFER VECTORS CONCEPT AND ACOUSTIC RADIATION ANALYSIS OF THE APPLICATIONS

Abstract

In the latest several decades, NVH (Noise-Vibration-Harshness) has become an important indicator for quality and comfort of cars. The structural acoustic performance of a car becomes an important issue in the design process. In car structures, the vibration of plates is not self-generated, but passed from the frame structure. Thus, the frame structure of a car is the important source of vibration and noise. The topography optimization, an optimization technique based on shape selection, is applied to problems of structural acoustic optimization. A case study on the application of topography on the frame structure is illustrated. The paper presents Acoustic Transfer Vectors and Modal Acoustic Transfer Vectors and their use in acoustic radiation prediction, particularly from the surfaces of frame structure. Acoustic Transfer Vectors are input-output relations between the normal structural velocity of the radiating surface and the sound pressure at a specific point in the field. The Modal counterpart gives a similar relation, but expressed in the modal coordinates of the radiating structure. The structural response, computed with a standard FE model such as NASTRAN, can be determined either directly in the frequency domain using a modal model, and this provides the boundary conditions for the acoustic radiation.