COMPUTING ACOUSTIC-WAVE PROPAGATION IN ST RUCTURES BY DECOMPOSITION USING FUNCTIONS OF ACOUSTIC RADIATION

In this paper , a superposition method is presented that allows the co mputation of acoustic fields radiated by vibrating structures . Basica lly , the method of superposition applied to sound radiation consists in modelizing the vibrating structure by fictitious acoustic sources l ocated inside it . The sources used can be punctual ones such as monop oles or dipoles ; we have developped surfaciq sources which have the a dvantage of a large spatial bandpass By a numerical procedure complex amplitudes of these sources are determined so as to satisfy the bounda ry conditions usually normal velocity which is either calculated or me asured Usually authors try to minimize the difference between the know n velocity and the approximated one in the least mean square sense Thi s method implies numerical peculiarities since it leads to ill-conditi onned linear equations system. The convergence criterium in terms of v elocity is very hard to achieve and it does not take into account radi ation efficiency We present a method in which we add the acoustic stre ngth of the structure as an auxiliary condition .