Wave finite elements in guided elastodynamics with internal fluid

This paper presents a general formulation which addresses the issue of wave propagation in guided elastodynamic structures filled with acoustic fluid. The formulation is based on a finite element description of periodic systems. It leads to a general spectral problem, whose eigenvalues and eigenvectors are related to the free propagating wave properties. The formulation incorporates many simplified elastodynamic models of an analytical nature. Here, the formulation is stated for a fluid–structure guided medium. The free and forced frequency response of such elasto-acoustic system is fully formulated in the wave space. Reduction of the wave basis is discussed. Numerical simulations and comparisons with classic simplified theories clearly shows the pertinence of the proposed formulation. Moreover, it is clearly shown that, unlike most of the existing theories, the proposed formulation is not low frequency limited.