Abstract: We discuss briefly theoretical background of FEM and WBM and mathematical description of coupled FE/WB approach.FEM and WBM show advantages in wide application and high convergence rate,respectively.A coupling of predication tools benefits from advantages of both.The basic idea is to replace parts in the finite element mode,which have simple geometrical shapes,by much smaller wave models.It results in a coupled model with less degree of freedom.This allows a further refinement of model,which leads to an improved accuracy at higher frequencies and reduces number of degree of freedom by modal reduction techniques.Numerical example indicates that the proposed method has potential in covering a range with mid-frequency.

Key words: vibro-acoustics, numerical modeling, finite element method, Trefftz approach