MECHANICAL EXCITATION OF PLATES AT LOW-FREQUENCIES - A DISCUSSION ON THE USE OF THE BENDING WAVE-EQUATION

This paper is devoted to theoretical analyses of mechanical excitation of thin plates at low frequencies. The cases of excitation of an infi nite plate with a point force or a line moment are taken as examples. It is shown that the use of the usual bending wave solution can give a substantial error in the estimate of the bending wave amplitude. This finding has practical implications not only for the input mobilities, but also in a more general way as the solution for point excitation i s often used as a Green's function for more complex problems, and as t he line mobility forms of models for the transmission of structure-bor ne sound at plate junctions. Results which are qualitatively can be ob tained with the Mindlin plate theory but it is also shown that the com plete three-dimensional plate theory must be used in order to get quan titatively correct results.