The dynamic characteristics of a rotor supported on ball bearings with different floating ring squeeze film dampers

• Two different floating ring squeeze film dampers (FSFD) were studied.
• The performance of FSFD was investigated in preventing bistable operation.
• The performance of FSFD was investigated in preventing non-synchronous motions.
• The performance of FSFD was investigated in preventing sudden unbalance response.
• The performance comparisons of different FSFD were also investigated.

Two different floating ring squeeze film dampers (FSFD) were studied, one has a single oil film, which is referred as FSFDS, and the other has a double layer oil film, which is referred to as FSFDD. To investigate the dynamic characteristics of FSFDS and FSFDD, two rotor dynamic models are established. In the model, the coupling effect between rotor, ball bearing and FSFDS/FSFDD is considered. Then an efficient numerical integration approach has been employed to conduct the investigation into the rotor system. Numerical results show that the performances of FSFDS and FSFDD are better than the traditional SFD, but worse than FSFD that has a double layer oil film and does not contain the elastic support of a floating ring, in preventing bistable, non-synchronous and the transient amplitude of the sudden unbalance response. They have better performance than FSFD in controlling the transient process of the sudden unbalance response by increasing the support stiffness of the floating ring. But it may lead to the bistable response.