Modal Reduction Method for Vibrational Analysis of Structures Partially Filled With Internal Liquids

Abstract

In the framework of the vibrational analysis of structures, we propose a method to take into account the internal liquids (like fuel) in the structure modelling. Since the “classical” added-mass hydroelastic model cannot be used for slender and flexible structures such as space launchers or civil aircraft wings (because the decoupling assumption of sloshing and hydroelasticity is not valid for such structures), we propose here a revised hydroelastic formulation which takes this coupling into account. Since this model introduces in the system a great number of degrees of freedom for the fluid, we will present a reduction method using the Ritz-Galerkin projection onto the fluid sloshing modal basis. A discretization of the reduced equations by the finite element method will be proposed and the convergence rate of this modal reduction method will be discussed on an application example.