The vibrational source strength descriptor using power input from equivalent forces: a simulation study

Simple, yet reliable methods for the approximate determination of the vibratory power supplied by the internal excitation forces of a given vibrational source are of great interest. One such method that relies on the application of a number of “equivalent forces” and measurements of the mean squared velocity on either the source or the receiving structure is studied in this paper by means of computer simulations. The study considers a simple system of two flexural beams coupled via a pair of springs. The investigation shows that a relatively small number of equivalent forces suffice for determining the vibratory power if applied at carefully chosen driving points, and that the velocity measurements for the method generally should be taken on the source structure. The real part of the supplied power can generally be very well estimated by the method, whereas the imaginary part is prone to somewhat larger estimation errors. The reliability of the estimate is also studied under different conditions with respect to coupling stiffness between source and receiver and relative mobility of the source and receiving structures