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*FREQUENCY

Keyword type: step

This procedure is used to determine eigenfrequencies and the corresponding eigenmodes of a structure. If the PERTURBATION parameter is used in the *STEP card, the load active in the last *STATIC step, if any, will be taken as preload. Otherwise, no preload will be active.

There are no parameters. Default and only solver is the ARPACK solver [12]. The eigenfrequencies are always stored in file jobname.dat.

First line:

- *FREQUENCY

Second line:

- Number of eigenfrequencies desired.
- Accuracy desired (default: 0.01).
- # Lanczos vectors calculated in each iteration (default: 4 * #eigenfrequencies).
- Maximum # of iterations (default: 1000).

It is rarely needed to change the defaults.

    Example:

    *FREQUENCY
    10

requests the calculation of the 10 lowest eigenfrequencies and corresponding eigenmodes. For the accuracy, the number of Lanczos vectors and the number of iterations, the defaults are taken.

Example files: beam8f, beamf.