Dynamic Properties of Modified Systems

Abstract

A set of methods is presented for convenient calculation of the changes in the frequency and shape of any mode of undamped vibration of a structure due to changes in the parameters of the system. Previously reported methods of similar type did not include the possibility of changes in the system that increase the number of degrees of freedom. The extension to cases in which degrees of freedom are added is effected by perturbation methods. In particular, the methods presented can treat close or multiple frequencies. Some sample numerical results are given for separated frequencies and multiple ones