Effect of support stiffness and damping on stability characteristics of herringbone-grooved aerodynamic journal bearings mounted on viscoelastic supports

Journal bearings mounted on viscoelastic supports are often used to improve the stability. However, proper support conditions have not been established especially for herringbone-grooved aerodynamic journal bearings. This study aims to make clear the effect of support stiffness and damping on the stability characteristics of the bearings. For that purpose, the linear perturbation analysis and the nonlinear transient analysis are performed for various viscoelastic support conditions. This investigation reveals that the groove configuration that gives the highest threshold speed of whirl instability changes with the viscoelastic support conditions. This investigation also reveals that it is possible to stabilize the bearings by viscoelastic supports. However, the threshold speed for lower damping support conditions decreases rather than that for rigid support condition.