PARAM, LFREQ
Bulk Data Entry Used to remove the Rigid Body Modes from the Modal Space.
| Parameter | Values | Description |
|---|---|---|
| LFREQ | <Real>(Hertz) Default = None Defaults: If PARAM, LFREQ is input without specifying a value, the solution runs into an error. |
Modes with frequencies
less than LFREQ are not used in Modal Frequency
Response and Modal Transient Analysis. LFREQ can
be used to remove Rigid Body Modes from the Modal
Space. LFREQ is used in Response Spectrum Analysis to specify the lower bound of the frequency range of interest for modal combination. |
Comments
- The Residual Vector (RESVEC) calculation still includes the modes below LFREQ so that they are normalized correctly.
- Modes that are eliminated by PARAM,
LFREQ will display:
- an "S" next to the mode number, if the mode is eliminated by MODESELECT in one subcase and PARAM, LFREQ in another subcase, or
- an "L" next to the mode number, if the mode is eliminated only by PARAM, LFREQ.