Prediction of mechanical noise by field-matching wave superposition method with boundaries

Abstract

Based on wave superposition method (WSM), radiated noise can be predicted quickly by monitoring the vibration data on machine surface. However, this method may produce great error for complex vibration distribution. The main cause is the improper configuration of equivalent sources. In order to solve this problem, an equivalent source configuration based on the least mean square method (LMS) is put forward for typical structure in this paper, in which a few reference points of sound field pressure should be measured ahead to search the optimal equivalent source position automatically. Since the structure has been equivalent to an array of monopole sources by WSM, the prediction for mechanical noise with boundaries can be realized by changing Green function. The result shows that the radiated noise of structure, for different excitations, can be predicted precisely from the surface velocity by WSM once the optimal equivalent source position is determined by LMS using the reference points of sound pressure field.