The initial request related to applying numerical simulations to mitigate the risk of damaging satellite critical components/subsystems before the actual structure (satellite flight model) is submitted to acoustic tests representative of launch conditions.
In fact during the rocket launch, light and thin structures on satellites are subjected to the most severe acoustic levels. These structures are sensitive to the coupling between the acoustically induced movements of the surrounding air (fluid) and the structural dynamic behavior.
As satellites are very expensive structures, it’s important to perform preliminary calculations to check structural reliability of the most sensitive components before they have to endure the launch environmental conditions.
The ASTRYD simulation software has been developed by Metravib in order to provide an efficient solution describing fluid-structure interactions and predicting the behaviour of light structures submitted to a severe acoustic environment.
To create the ASTRYD software and to adapt it to the spatial issues, Metravib started from calculation software developed during a common research with CEA (French Commissariat à l’Energie Atomique) which dealt acoustic pressure diffraction issue on concrete buildings submitted to an explosion wave.
As the shock wave is an impulsive, short time phenomenon, the calculation code was developed in the time domain, based on a retarded potential technique.
The existing calculation code was progressively adapted to the new class of problems to be solved, thus integrating the dynamic behavior of the structure (modal parameters computed using a FEM code, then projected onto the acoustic meshing) with an accurate description of the fluid-structure coupling on the boundary element mesh (BEM). Quite an intensive work has been accomplished to improve the software performance, notably with the latest introduction of the NGTD algorithm (Non uniform Grid Time domain).
The ASTRYD software allows vibro-acoustic calculations in weak to moderate coupling classes of fluid/structure problems. It has been successfully applied in a number of satellite projects like Herschel-Planck, Amos, Integral, Artemis to name a few.