Shaft Bending to Zero Nodal Diameter Disc Coupling Effects in Rotating Structures Due to Asymmetric Bearing Supports

摘要

In a flexible shaft-disc assembly, coupled shaft-disc vibration modes are likely to occur, provided that the natural frequencies of the two components are close. It is well known that the shaft axial and bending modes can couple with the zero and one Nodal Diameter (ND) modes of the disc, respectively. In a previous work, it has been shown that in presence of asymmetric axial-radial bearing supports, combined axial-bending shaft modes can occur, which are further impacted by gyroscopic forces when the system is rotating. Extending the previous findings, the impact of disc flexibility on this new coupling family has been investigated in more detail. The obtained results show the emergence of shaft whirling modes with an axial component, that can couple with 0ND or 1ND disc modes. As a result, a 0ND disc mode can possibly be excited by an out of balance mass on the shaft, leading to a previously unobserved vibration behaviour.