For a load case of the "Modal Analysis" type, you can define another load case whose stiffnesses represent the initial position for the dynamic analysis. To do this, activate the Consider initial state check box and select the load case from the list.
The
button to the right of the list opens the "Initial State Settings" dialog box (see the image
Defining Type of Initial State
). Define the type of the initial state here (only the "Stiffness" type is currently available).
Using this option, you can determine the stiffness of a model if tension members fail in a load case, for example. The stiffness from this load case—that is, the "residual model" without failed tension members—is then used in the modal analysis. The softer system has a corresponding effect on the eigenvalues.
The "Consider initial state" function is described generally for load cases in the chapter Load Cases of the RFEM manual.
