Comparing Beam Rotor and Solid Rotor

A comparison of Campbell diagrams must be done from the same frame of reference. Therefore, a Campbell diagram obtained from the Beam Rotor interface should be compared with a Campbell diagram in the fixed frame from the Solid Rotor interface. Because frame acceleration forces are modeled explicitly in the Solid Rotor interface, stress stiffening effects due to centrifugal forces are important in order to obtain the correct natural frequency. This can be done by setting up a stationary analysis to obtain the prestress in the structure caused by centrifugal forces, followed by an eigenfrequency analysis with the prestressed state as a linearization point. This effect is very important for cases where an object with a large moment of inertia on the rotor is tilted significantly in the mode shape.