About structural dynamic reanalysis

Abstract

The methods of structural dynamic modification, especially those with their roots in finite element models, have often been described as reanalysis. The present paper deals with the problem of improving of dynamic characteristics some structures. New dynamic modification procedure is given as using distribution of potential and kinetic energy in every finite element is used for analysis. Studying the dynamic behavior of structures can be predicted responses due to changes in its shape, size or design elements change materials. The main goal of dynamic optimization is to increase natural frequencies and to increase the difference between them. Especially, the lowest frequencies are the most interesting and those whose values are close to frequency excitation force in the system. Consequently these are further characteristic areas: I The elements with kinetics and potential energy, which values are negligible comparing to other elements. II Elements with the kinetics energy greater than the potential energy. III Elements with the potential energy greater than kinetics. IV Elements with kinetics and potential energy, which values are not negligible comparing to other elements. By observing diagrams of the distribution difference of the increment potential and kinetic energy on the modes shape of interest, modification can be suggested. The application of mentioned procedure of real structures shows its practical side.