The inverse vibration problem for fixed beam submerged in fluid

Abstract

Abstract Description of dynamic behaviour of the structures is based on the mass, damping and stiffness matrices. Unfortunately, this description is inapplicable in case of the fluid-structure interaction (FSI), because the matrices of system, which consists of the structure and ambient fluid, are generally not known. The matrices of system, describing the FSI, can be determined by solution of inverse vibration problem, which is an approach employing the spectral matrix and modal matrices of analysed system. The eigenvalues for creation of the spectral matrix are determined based on experimental measurement. The results of experiment can be verified by numerical simulation. The modal matrices of structure submerged in fluid can be given by experiment, which is not simple in FSI problem, or by acoustic modal analysis. Third approach for determination of the modal matrices works with the assumption, that the eigenvectors of structure are not influenced by the fluid and are identical to the eigenvectors of structure without the ambient fluid. This assumption is generally correct for majority of FSI problems. Described method is demonstrated on determination of the matrices of dynamic systems of the fixed beam submerged in water.