Principal parametric resonance zones of a rotating rigid shaft driven through a universal joint

The two models for the motion of a driven shaft coupled via a U-joint to auniformly rotating driving shaft were presented. In the first model, shaft was treated as rigid and flexible in the second model. The analytic expressions for computing the principal parametric zones were discussed. It was shown that the parametric instabilities in the shafts of proportion were due to the rigid body modes. The minimum amount of damping to move then principal parametric zones was determined using these expressions