Learning Forum

[Bhargava Sista]

How is unbalanced mass defined in rotordynamics?n

[mrife]

The unbalanced mass is defined by a force, where the force is associated with the mass and eccentricity (distance from point to center or 'rotating radius' in WB Mechanical terms). We do it this way because we use a stationary frame of reference, and so the FEM is not actually 'rotating' in the simulation, but the effect of rotation is accounted for in the gyroscopic damping matrix. In a similar way, the unbalance force must be applied to the center, and based on the real and imaginary components, the effect of the unbalance (via forces) is applied to the system.n