Acoustic characterization of silica aerogel clamped plates for perfect absorption

A multiobjective optimization procedure is employed to retrieve the viscoelatic parameters of silica aerogel clamped plates. This retrieval method preserves the aerogel sample integrity and, in contrast to the existing ones, relies on the minimization of two different cost functions. The first one, namely J(1), is related to the reflective properties of clamped plates backed by a rigid cavity, while the second one, namely J(2), concerns both the reflectance and transmittance spectra measured in transmission configuration. The recovered parameters are in agreement with previously reported values in the literature. In addition, they are also supported by designing structures for perfect absorption (100% of absorption), which has been validated experimentally. Aerogel plates can be therefore used as innovative building units of artificial structures for the broadband absorption of sound.