Acoustic sandwich panel with several degrees of freedom has two or more cellular layers of different dimensions with porous separators

摘要

The sandwich panel, made from metals, thermoplastics or composition materials, has a resistive layer (14) forming its front face and a cellular structure (16) made from at least two cellular layers (18a, 18b, 18c) with porous separators (24) between, and a reflector (17) forming the rear face. The cellular structure is made from layers with cells of different dimensions, positioned alternately. The difference in the cellular networks of the layers is about 30 mm, and the structure has, for example, a layer with relatively large cells between two layers having smaller cells.