MODESELECT

Format

MODESELECT (type) = n

Mode selection based on arbitrary mode numbers.

Alternate Format 1

MODESELECT (type, LMODES = lm)

Mode selection based on lowest modes.

Alternate Format 2

MODESELECT (type, LMODENM = lom, HMODENM = him)

Mode selection based on a range of mode numbers.

Alternate Format 3

MODESELECT (type, LFREQ = lof, HFREQ = hif, UNCONSET = m)

Mode selection based on a range of frequencies.

Definitions

Argument	Options	Description
`type`	<STRUCTURE, FLUID>	STRUCTURE (Default) The MODESELECT command references modes associated with structural analysis only. FLUID The MODESELECT command references modes associated with fluid analysis only.
`n`	n > 0, n < 0 (Integer)	n > 0 Set identification number `n` of a set of mode numbers. The modes corresponding to the mode numbers specified in set `n` will be included in the analysis. If no such set exists, then mode `n` will be included in the analysis. n < 0 Set identification number \|n\| of a set of mode numbers. The modes corresponding to the mode numbers specified in set \|n\| will be excluded from the analysis. If no such set exists, then mode \|n\| will be excluded from the analysis.
`LMODES`	lm (Integer > 0)	Specifies the number of lowest modes to be selected.
`LMODENM`	lom (Integer > 0)	Specifies the lower bound of the mode number range for selecting modes. 3
`HMODENM`	him (Integer > lom > 0)	Specifies the upper bound of the mode number range for selecting modes. 3
`LFREQ`	lof (Real ≥ 0.0)	Specifies the lower bound of the frequency range for selecting modes. 4
`HFREQ`	hif (Real > lof ≥ 0.0)	Specifies the upper bound of the frequency range for selecting modes. 4
`UNCONSET`	UNCONSET	This flag indicates that the following fields specify a single mode or a set of modes for unconditional inclusion or exclusion. When `UNCONSET` is used, the bounds of the frequency range (`LFREQ` and `HFREQ`) must be specified for the selected modes.
`m`	m > 0, m < 0 (Integer)	m > 0 Set identification number `m` of a set of mode numbers. The modes corresponding to the mode numbers specified in set `m` will be unconditionally included in the analysis. If no such set exists, then mode `m` will be unconditionally included in the analysis. m < 0 Set identification number \|m\| of a set of mode numbers. The modes corresponding to the mode numbers specified in set \|m\| will be unconditionally excluded from the analysis. If no such set exists, then mode \|m\| will be unconditionally excluded from the analysis.

Comments

The MODESELECT I/O Options Entry is only supported in Modal Frequency Response Analysis, Linear Modal Transient Response, Complex Eigenvalue Analysis and Aeroelastic Flutter Analysis. It is not supported in Response Spectrum Analysis.
Multiple MODESELECT entries are allowed in a model. MODESELECT entries can be specified above the first subcase or within each subcase.

If LMODENM is specified without HMODENM, a default value of 10000000 (ten million) is assumed for HMODENM. If HMODENM is specified without LMODENM, a default value of 1 is assumed for LMODENM.

Defaults	LMODENM	HMODENM
	specified	1.0E+7
	1	specified

If LFREQ is specified without HFREQ, a default value of 1.0E+30 is assumed for HFREQ. If HFREQ is specified without LFREQ, a default value of 0.0 is assumed for LFREQ.

Defaults	LFREQ	HFREQ
	specified	1.0E+30
	0.0	specified

When the MODESELECT Case Control command is used in conjunction with the parameter LFREQ, the MODESELECT Case Control takes precedence.
If the use of MODESELECT results in all or none of the computed modes for use, you are informed with a message.
The faster method for modal frequency response analysis (activated by PARAM,FASTFR,YES) cannot be used in conjunction with MODESELECT.
Modes that are eliminated by MODESELECT will display an "S" next to the mode number, if the mode is eliminated by MODESELECT in one subcase and PARAM, LFREQ or PARAM, HFREQ in another subcase, or an "M" next to the mode number, if eliminated by MODESELECT in at least one subcase.