MODESELECT
I/O Options and Subcase Information Entry Used to select a subset of computed modes in modal dynamic analysis subcases.
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> 

n  n > 0,
n < 0 (Integer) 

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) 

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.