Bifurcation analysis of a Jeffcott rotor with a bearing clearance: Numerics and experiments

Here, (Nsx, Nsy)T = Ns stands for the normal force produced when the rotor hits the snubber ring. It is computed as the normal component of the snubber ring force Fs (see Fig. 3), which is given by

When there is no contact (D <γ), the equations 3 and 4 reduce to

and when the snubber ring and the rotor are in contact (D ≥ γ), the motion of the snubber ring is assumed to obey the Principle of Minimum Total Potential Energy and thereby χt and ϒt are computed.