Wave intensity analysis of high frequency vibrations

In the statistical energy analysis (SEA) approach to high frequency dynamics it is assumed that the vibrational wavefield in each component of an engineering structure is diffuse. In some instances the directional filtering effects of structural joints can lead to highly non-diffuse wavefields, and in such cases sea will yield a very poor estimate of the vibrational response. An alternative approach is presented here in which the directional dependency of the vibrational wavefield in each component is modelled by using a Fourier series. It is shown that, if required, the resulting energy balance equations may be cast in the form of conventional SEA with the addition of ‘non-direct’ coupling loss factors. The method is applied to the bending and in-plane vibrations of various plate structures and a comparison is made with exact results yielded by the dynamic stiffness method. A significant improvement over conventional SEA is demonstrated.