Spin Softening
For prestress modal analyses, Creo Simulate automatically compensates for the effect of relative motions when a centrifugal load is present on a model. The software adjusts the stiffness matrix to account for this effect, which is referred to as spin softening.
The spin softening modification term includes only derivatives of centrifugal loads that are due to angular velocity, and those with displacements. It does not include derivatives of centrifugal loads that are due to angular acceleration, nor does it affect moment terms for beams or shells, or derivatives due to rotations.

Springs are allowed in prestress analysis, but Creo Simulate does not compute stressstiffness effects for springs. For a prestress modal analysis on a model with centrifugal loads, a spring, and a mass, the system stiffness decreases due to spin softening, and there is no stressstiffening for the spring.
