Advanced Finite Element Method for the Vibro-Acoustic response of plate-cavity systems

Aerospace vehicles are subject to broadband, sometimes severe, vibroacoustic and structure-borne excitations of various origin, which can danger the availment of the payload on board and the electronic equipment, and consequently the unsuccess of the entire mission. It is therefore important for the modern industry the development of analytical and numerical tools that can accurately predict the vibroacoustic response within structures of various geometries and subject to a combination of vibroacoustic excitations in order to mitigate unwanted phenomena able to compromise the whole mission. Nowadays, A lot of research has been conducted on the correctly modelling of wave propagation characteristics within representing the reactivity of the structure in noise field. As sake of simplicity, we will deal a simple test, coupled plate-cavity, where numerical modeling techniques risen are tipically based on deterministic approaches. The plate structure is often modeled by the finite element method and the Kirchhoff/Mindlin are mostly assumed to describe the through-the-thickness variation of the resultant displacement field. These simple assumptions of modeling the plate clearly reduce the required computational effort, but can also introduce huge errors in the prediction of the plate dynamic response and consequently affect the sorrounding acoustic pressure field, where noise is risen. In this work, a powerful notation has been used: Carrera’s Unified Formulation, whose permits to obtain a wide class of refined plate theories (LW) with a unique formulation, providing an optimal element to completely describe the complex risen effects due to plate layouts and for higher frequency ranges. This work was conducted through the use of Actran Software, in order to conduct research in Vibro-Acoustic field. Structural Vibroacoustic interaction is modeled and analyzed using the finite element method coupling (interfaces), to solve the structure-acoustic coupled interaction for the noise radiation problem in a plate cavity system. The important keywords are the complete understanding of the generation of noise, its radiation in operating structure and the mitigation of the negative effect in order to improve the functionality of the system. Structures are generally characterized by the use of composite materials of various configurations/complexity in term of thicknesses, as well as geometries. Acoustic load and high frequency vibration can strictly and disadvantageously affect structures that represents a significant issue in spacecraft structures. Because of the extensive geometric complexity of structures, the usage of Finite Element (FE) modelling is frequently inevitable within the aerospace industry. The use of such models is limited mainly because of the immensity computation time required for calculations.