A PERTURBATION APPROACH FOR THE RESPONSE OF DYNAMICALLY MODIFIED STRUCTURAL SYSTEMS

The problem of the structural analysis under changes of dynamical para meters is of particular interest. This is due to the fact that often t he real structures are different from the predicted ones. In this pape r, an unconditionally stable step-by-step procedure, able to evaluate the deterministic response of linear structures with modifications, is presented. The proposed procedure requires the evaluation of the tran sition matrix, which is the fundamental operator of the step-by-step s olution, by means of a perturbation approach. This technique overcomes the difficulties connected with the evaluation of the eigenproperties of the modified structures usually required to obtain the transition matrix. Furthermore, it is successfully applicable, even in the presen ce of large structural modifications. An application to a simple case shows the advantages of the method proposed herein. (C) 1998 Elsevier Science Ltd and Civil-Comp Ltd. All rights reserved.