NORMAL-MODES OF VIBRATION FOR CONTINUOUS ROTORS WITH SLOW TIME VARIABLE MASS

A method based on the invariant manifold approach to normal modes is g eneralized for obtaining normal modes of vibrations for rotors with sl owly varying parameters and the dynamics of modes is analysed in this paper. A rotor with slow time variable mass with cubic non-linearities is given as an example. The motion obtained by the mentioned method i s compared with the results of the standard Galerkin procedure. The no n-linear ordinary second order differential equations which govern ind ividual modal dynamics are solved numerically. The influence of reacti ve force and mass variation on normal modes of vibrations is also anal ysed. (C) 1997 Elsevier Science Ltd.