Impact of the acoustic transmission path on the vibro-acoustic performance of sandwich panels with structural cores with bandgap behavior

In the search for lightweight and compact structures with favorable vibro-acoustic performance, periodic structures such as phononic crystals and locally resonant metamaterials have shown potential. Recently, these periodic structures are included between two panels in a sandwich configuration to combine the interesting vibro-acoustic performance of the core with the potential load-carrying capacity of the sand-wich configuration. During the design and numerical analysis of the vibro-acoustic performance of these structures, commonly only the structural connection between the plates is considered. However, next to the structural connection, also an acoustic transmission path is present between the plates of the sand-wich configuration in reality. Because of this, the promising performance due to the structural decou-pling of the double panel configuration by the bandgap behavior of the periodic core predicted with the analyses only considering the structural connection, are often not attained in experimental measure-ments. In this work, the impact of the ignored acoustic transmission path on the sound transmission loss of sandwich panels with structural periodic cores which exhibit bandgap behavior, is investigated. It is shown that the sound transmission follows the path of least resistance. Therefore, it is crucial to consider both the structural as the acoustic path in the partitions during the design phase to correctly predict the vibro-acoustic performance of these novel sandwich panel configurations.(c) 2022 Elsevier Ltd. All rights reserved.