Different modeling methodologies for rotor-system on ball bearing cartridge with squeeze film damper

Ball bearing-squeeze film damper (BB-SFD) cartridges are increasingly employed in high-speed rotating machinery, such as automotive turbochargers and gas turbines, due to their ability to reduce friction and enhance rotordynamic stability. Despite their growing use, accurately modeling the dynamic behavior of these systems remains challenging. This is primarily due to the nonlinear characteristics of oil film forces and the complex interaction between the bearing components particularly the outer race and the squeeze film lands. This study presents four distinct modeling approaches for the BB-SFD cartridge: single-mass, two-mass, beam-element, and rigid-body formulations. The squeeze film damper is represented using an open-ended short-bearing configuration, with oil film forces computed based on the motion of the outer race. It is observed that gravitational effects cause the outer race to become off-centered, resulting in nonlinear dynamic behavior that significantly influences system response. An automotive turbocharger is used as a case study to evaluate the performance of each modeling approach. Experimental modal analysis and dynamic testing are used to verify the simulation model. The two-mass formulation offers a favorable balance between computational efficiency and accuracy among the models considered. The rigid-body model provides a generalized framework that can be extended to other bearing configurations, including journal bearings and rigid supports. By addressing limitations in existing models and incorporating outer race dynamics, this work contributes to the development of more reliable and efficient simulation tools for high-speed rotor-bearing systems.