A HYBRID ENERGY METHOD FOR PREDICTING HIGH FREQUENCY VIBRATIONAL RESPONSE OF POINT-LOADED PLATES

摘要

Modelling of the far-field energy distribution and power flow in point-loaded finite plates is considered. First, the two-dimensional conductivity equation governing the energy distribution in a plate is derived from fundamental energy and intensity considerations. The derivation, previously unreported, illustrates the basic assumptions and limitations of the conductivity method. A hybrid model is then developed in which contributions to the direct and reverberant fields are estimated separately. The direct field component is approximated by the far-field response of an infinite plate; the reverberant contribution is governed by a homogenous conductivity equation with a reflected power distribution along the boundary of the plate. The partition of power between the direct and reverberant fields is approximated by assuming a circular plate with an equivalent surface area. The method is found to be effective for predicting the spatial variation in the response when both the direct and reverberant fields participate strongly, a case not well predicted by statistical energy analysis, or by the conductivity method. The method is applied to examples of a centrally loaded square plate, and a rectangular plate with two uncorrelated point loads. (C) 1997 Academic Press Limited. [References: 19]