Abstract
The wave analysis efficiently elucidates wave propagation on mechanical structures. Medium of wave propagation is called waveguide. The waveguide which has complicated configurations are generally modelled by a finite element method. Whereas modelling technique for vibration analysis using finite element method is practical, that for wave analysis is behind in technology. The wave propagation characteristics (e.g. phase velocity and group velocity) maybe represent by a wavenumber. In this paper, the influence of a model reduction was investigated in analytical accuracy in terms of wavenumber.