A numerical simulation of multiple-shaker model testing

Abstract

A system of software has been developed for the simulation of structural dynamic modal testing by the method of steady-state sinusoidal excitation by discrete shakers. An analytical method commonly known as Asher's Method was employed to optimize the shaker forceamplitude distributions for the purpose of isolating individual modes of vibration. The method involves the use of transfer functions of the structure to determine the natural frequencies and force-amplitude distributions. Each force-amplitude distribution was used in the calculation of the coincident and quadrature displacements for the associated modes of vibration. Narrow-band frequency sweeps were used to determine the purity of isolated modes through the use of coincident-quadrature response plots in the Argand plane. In addition, modal energies of partially isolated modes were examined for the effects of interfering modes, again as a measure of modal purity.