Dynamic characteristics of a disk-drum-shaft rotor system with rub-impact

The dynamic model of a disk-drum-shaft rotor system with rub-impact is established and its dynamic characteristics are analyzed. According to an elastic impact model and Coulomb's friction law, two rub-impact force models are firstly developed which corresponding to the disk-stator contact and the drum-stator contact, respectively. Taking into account, the coupling of the whole rotor whirl and the local drum vibration, the dynamic model of a disk-drum-shaft rotor system with the disk-stator and the drum-stator rubbing is established by employing Sanders' shell theory and Lagrange equation. The numeric results reveal that the continuous increase in rotating speed, disk mass eccentricity, and stator radial stiffness induces alternation of periodic-one motion of the disk without diskstator contact, periodic-one motion with disk-stator full annular rubbing and the disk-stator partial rubbing region in which the quasi-periodic and periodic motions of the disk appear alternately. In addition, the motion of the drum is synchronous with that of the disk and has three situations, i.e., un-deformation, deformation with one circumferential wave, and periodic and quasi-periodic vibrationwith drum-stator rubbing. Due to the effects of the drum, the rotating speed corresponding to the start of the disk-stator full annular rubbing in the disk-drum-shaft rotor system is smaller than that in the disk-shaft rotor system, and there is only one disk-stator partial rubbing region which is near the critical speed of rotor system. What is more, compared with parameters of the disk, those of the drum can only affect the motion of the rotor system slightly.