Import of Stiffness Modifications
Tips & Tricks
In RF-/DYNAM Pro - Natural Vibrations, it is possible to import axial forces and stiffness modifications from any Load Case (LC) or Load Combination (CO). You can modify material, cross‑section, member and surface properties and activate those modifications in the LC/CO calculation parameters.
You can also import stiffnesses from RF‑/CONCRETE and deactivate members or surfaces and thus import a different structural system. Axial forces and failing members are imported from the set LC/CO. All stiffness modifications are initial conditions for the eigenvalue analysis performed in RF‑/DYNAM Pro, a linear calculation is performed.
When you want to consider axial forces only (for example prestress in cables or consideration of the P‑Delta effect) make sure that no stiffness modifications are activated in the calculation parameters of the imported LC/CO.
When you want to study certain stiffness modifications or deactivated members only, make sure you create a LC containing no loads but the stiffness modifications you are interested in.
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Dynamic analysis of natural frequencies and mode shapes of member, surface, and solid models