SHIFTING RESONANCES FROM A FREQUENCY BAND BY APPLYING CONCENTRATED MASSES TO A THIN RECTANGULAR PLATE

The vibration of a thin, simply supported rectangular plate carrying a number of concentrated masses is considered. It is shown that the add ition of the masses has the effect of reducing the eigenvalues within certain bounds. Two numerical methods are developed for calculating th e eigenfunctions, eigenvalues and frequency response of the mass loade d plate. These are employed in an attempt to drive a gap in the eigenv alues directly below 110 Hz for a particular test case of a plate carr ying five concentrated masses. A small gap is achieved, but to produce a larger gap many more masses would be necessary. The frequency respo nse and eigenvalues are relatively easily obtained and compare well wi th those obtained by using the finite element method. (C) 1996 Academi c Press Limited