Solid Rotor

The Solid Rotor interface offers the most general approach for modeling a rotor based on a continuum description. Solid elements are used to define the rotor assembly, and the rotor is represented by its three-dimensional geometry. Governing equations for this interface are described in a rotating frame. This interface automatically accounts for frame acceleration forces due to rotation of the rotor about its axis; hence the physical rotation is not needed to model the rotor. Also, the effect of spin softening and stress stiffening can be captured automatically using solid elements. The advantage of writing the governing equations in a rotating frame is that nonaxially symmetric rotors can be modeled too.

With the Solid Rotor interface, as opposed to a conventional rotordynamic analysis approach, the rotor vibration cannot be split into axial, bending, and torsional components. The results in this interface are obtained in a corotating frame and hence require a careful interpretation. For example, the whirl frequencies in this interface are relative to the axial rotation of the rotor. Therefore, the speed of the rotor, depending on the forward or backward whirl, is either added or subtracted from the frequency to obtain the corresponding frequency in a space-fixed frame. Furthermore, rotordynamic analysis using solid elements is computationally expensive, particularly in a case where you are interested in predicting the response of the rotor at various angular speeds. Therefore, use this interface only when you are interested in the detailed deformation and stresses.