Escuder Silla E., Ramis Soriano J., Alba Fernández J.

In this work, it is studied the acoustic and vibratory behavior of structures with the objective to evaluate its sound insulation by means of the technique of measurement without contact Near-field Acoustic Holography (NAH). This technique allows to obtain values of vibration velocity and pressure level of the multilayer panels submit to an acoustic excitation from measurements made with an array of microphones in a parallel and near plane (holograme plane) to the surface studied. It is used a box that has a window, in it the panels are placed. The box has two loudspeakers installed in the lateral ones with which broadband noise is generated in its interior. By the outer part of the box, the sound pressure in the hologram plane is measured. With these values and backpropagating the sound field, the sound pressure in the surface of the multilayer panels is obtained. The vibratory behavior of the different materials that form the multilayer panels is evaluated. The values of transmission loss obtained by means of NAH are compared with values facilitated by the Aisla 3.0 programme, that calculates the transmission loss according to the prediction model of the acoustic behavior of multilayer structures of Ookura&Saito. The transmission loss obtained from NAH and the transmission loss obtained by means of the prediction model of Ookura&Saito present acceptable similar results.