Natural Frequency - Modal with Load Stiffening

The natural frequency (modal) with load stiffening processor is very similar to the natural frequency (modal) processor. However, it can handle a situation when a part is under compression or tension at the same time that vibration is induced. Think of a violin or guitar string. If you tighten or loosen the screw, nothing is done to the string to change its mass or length, but the tone changes anyway. This effect makes music possible and engineers call it load stiffening.

One result of this analysis type is a series of restart files. The linear dynamic analysis type uses these files that use the method of modal superposition: Dynamic Design Analysis Method (DDAM), Frequency Response, Random Vibration, Response Spectrum, and Transient Stress (Modal Superposition). Therefore, the natural frequency analysis must be performed first.

Note:

Although the results from a Natural Frequency (Modal) with Load Stiffening analysis include displacements, use these displacements only to visualize the mode shape. The magnitude of the displacements is relative to each other. The natural frequency is a theoretical result due to unspecified dynamic loads, so the results cannot contain absolute displacements.
After performing the modal analysis, perform a vibration analysis in which loads are applied to the model, and the displacement results will have a physical value.