Abstract:

ESDU 98020 provides a computerized method for the estimation of transmission and reflection efficiencies of coupled plates. The plates are assumed to be thin, isotropic and coupled in an arbitrary manner either directly or through a beam. The theory takes into account the influence of bending, longitudinal and shear waves in the plates and bending, longitudinal and torsion waves in the beam. The program includes as options refinements such as incorporation of the effects of warping and shear for the beam together with the effects of the relative positions of the plate connections to the beam. The output of the program can be in one of two formats: either the transmission efficiencies as a function of angle of incidence at a defined frequency or diffuse field transmission efficiencies at the centre frequencies of either one third octave or octave bands or user-defined constant bandwidth bands. These diffuse field transmission efficiencies can for example be used to calculate coupling loss factors employed in Statistical Energy Analysis (SEA) models. Both formats can easily be imported into a spreadsheet for graphical representation. The program, ESDUpac A9820, accompanies this Item. Full details of input and output formats are provided and illustrated with worked examples.