Dispersion and excitability of guided acoustic waves in isotropic beams with arbitrary cross section

A finite element (FE) technique for computing the properties of guided waves that can exist in an isotropic beam of arbitrary cross section is presented. The FE model uses a two-dimensional mesh to represent a cross section through the beam and cyclic axial symmetry conditions to prescribe the displacement field perpendicular to the mesh. FE results are presented for plate and angle sections. Excitability functions are calculated and implications for transducer placement are considered.