HIGH-FREQUENCY RADIATION OF L-SHAPED PLATES BY A LOCAL ENERGY FLOW APPROACH

This paper describes a local energy approach to predict the high-frequency radiation of structures. This general approach is applied to a two-dimensional problem of the radiation of two joined semi-infinite, baffled plates, below their critical frequency. The first step consists in determining how energy travels through subsystems and, for this purpose, elementary waves are studied. Then some canonical problems are solved to describe the behaviour of waves impinging on boundaries. Below the critical frequency, flexural waves are subsonic and their radiation is due to diffraction phenomena. According to the locality principle, the corresponding canonical solutions are used in the whole system resolution; power sources are introduced on boundaries to account for energy exchanges and, with the assumption that waves are uncorrelated, the energy contributions of all sources are simply summed.