Vibro-acoustic analysis of micro-perforated sandwich structure used in space craft industry

In satellite telecommunications lightweight parabolic reflectors are made with multilayered composite material. During launcher lift-off and the first stage of the flight, vibro-acoustic excitations due to the thrust system and aerodynamic forces are the most critical. The random acoustic load applied to the antenna structure becomes very important and can damage the structure and its equipments. To reduce the acoustic loads, micro-perforated thin shell structures are used in order to reduce the acoustic load applied. CAD and numerical software tools are needed to design and optimise such structures. The computation of the acoustic load induced by a diffuse field on a micro-perforated structure is not classical. The aim of this study is to develop a numerical local impedance model to represent the effect of the perforation to be used within vibro-acoustic software.