SUMMARY. The undesired whirl of rotating machines can be reduced by elastic journal boxsuspension systems equipped with dry friction dampers. The critical speeds can be cut off by theadhesion of the friction surfaces and the whirl amplitude can be restrained throughout theremaining sliding range by a proper choice of the suspension-to-shaft stiffness ratio and of thesupport-to-rotor mass ratio. The dry friction forces counteract also efficiently the well knowndestabilising effect of the shaft hysteresis in the supercritical range. This lecture deals firstly withthe natural precession speeds, investigates the steady response to unbalance and defines the rangesof adhesive or sliding contact. Then, the stabilisation “in the small” of the hysteretic whirl bymeans of other external dissipative sources is studied applying the Floquet approach through aperturbation procedure, while the stability “in the large” is checked by the direct numericalsolution of the motion equation.
|Numero di pagine||0|
|Stato di pubblicazione||Published - 2009|