The variational theory of complex rays for the calculation of medium-frequency vibrations

A new approach called the "variational theory of complex rays" (VTCR) is developed for calculating the vibrations of weakly damped elastic structures in the medium-frequency range. here, the emphasis is put on the most fundamental aspects. The effective quantities (elastic energy, vibration intensity, ets.) are evaluated after solving a small system of equations which does not derive from a finite element discretization of the structure. Numerical examples related to plates show the appeal and the possibilities of the VTCR.