EIGEN

Calculate the eigenvalues of the structure

All elements that are active at the time where this calculation task is performed will be considered.

In this process, the masses of the elements are automatically considered as follows:

- Self-weight: All elements whose self-weight has been calculated with calculation task LCSELFW. This also includes the masses of elements, whose self-weight has been calculated with a task that calls up this calculation task, these are: CONCRETE, INSTBEAM, INSTCONC (install concrete girders). See Tasks.

- Superimposed dead loads: All elements for which a load case with a load item of the type LOADQY has been calculated where the option mass is activated in the property window of the load definition.

Arguments

lcsum

Currently not in use

nmode (number of modes)

Number of the eigenvectors to be calculated

naddv (number of additional vectors)

Number of the iteration vectors to be additionally considered to improve the convergence behavior, in case that the wished number of eigenvectors is not reached (subspace iteration method by Bathe)

resname (result name)

Result name; user-defined name under which the results of the eigenvalue calculation by means of displacements, forces and stresses are stored

The evaluated results can be addressed by their result names in the result presentation (tab Eigenmodes in the Result Data in Results).

xlsout (Excel output)

Name of the MS-Excel file, in which the results of the eigenvalue calculation should be stored in a respective subfolder of the project directory (eigenfrequencies and mass participation)