Abstract
The parametrically excited oscillations in a rotating shaft system where a periodic axial force is applied are studied theoretically. The treated model is a four-degree-of-freedom system where a disk is mounted on an elastic shaft with a circular cross section. We investigate the following: the forms of parametric excitation terms in the equations of motion, the kinds of parametrically excited oscillations which occur in this system, the influences of the shaft rotating speed on the width of the unstable regions, and so on. The differences from other kinds of parametrically excited systems, such as an unsymmetrical shaft system, an unsymmetrical rotor system, and a column system under a periodic axial force, are also clarified.
