CMSOPT,
CMSMETH, NMODE,
FREQB, FREQE,
FBDDEF, FBDVAL,
IOKEY, --,
--, ELCALC,
--, EIGMETH
Specifies component mode synthesis (CMS) analysis options.
CMSMETHThe component mode synthesis method to use. This value is required.
FIX | — | Fixed-interface method. |
FREE | — | Free-interface method. |
RFFB | — | Residual-flexible free-interface method. |
NMODEThe number of normal modes extracted and used in the superelement generation. This value is required; the minimum is 1.
FREQBBeginning, or lower end, of frequency range of interest. This value is optional.
The program
always sets this value to zero if the residual-flexible free-interface
method (CMSMETH = RFFB) or the free-interface
method (CMSMETH = FREE) is specified with
the RESVEC command.
FREQE Ending, or upper end, of frequency range of interest. This value is optional.
FBDDEFIn a free-interface (CMSMETH = FREE) or residual-flexible free-interface (CMSMETH = RFFB) CMS analysis, the method to use for defining free body modes:
FNUM | — | The number ( |
FTOL | — | Employ a specified tolerance ( |
FAUTO | — | Automatically determine rigid body modes in the calculation. This method is the default. |
RIGID | — | If no rigid body modes exist, define your own via the RIGID command. |
FBDVAL In a free-interface CMS analysis (CMSMETH = FREE), the number of rigid body modes if FBDDEF = FNUM (where the value is an integer from 0 through 6), or the tolerance to employ if FBDDEF = FTOL (where the value is a positive real number
representing rad/sec). This value is required only when FBDDEF = FNUM or FBDDEF =
FTOL; otherwise, any specified value is ignored.
IOKEY Output key to control writing of the complete transformation matrix on the .CMS file to the .TCMS file (FIX or FREE methods) or body properties to the .EXB file (FIX method).
CMS | — | Write the complete transformation matrix of the nodal component on the .CMS file. Refer to CMS File Format in the Programmer's Reference for more information on this file. |
TCMS | — | Write the transformation matrix of the nodal component defined by the OUTPR command to a .TCMS file. Refer to TCMS File Format in the Programmer's Reference for more information on this file. |
EXB | — | Write a body property input file (.EXB file) containing the condensed substructure matrices and other body properties for use with AVL EXCITE. Refer to ANSYS Interface to AVL EXCITE in the Substructuring Analysis Guide for more information. |
--, --Unused fields.
ELCALCElement calculation key (only supported for CMSMETH =
FIX):
NO | — | Do not calculate element results (default). |
YES | — | Calculate element results and write them to the .CMS file for the expansion pass. |
--Unused field.
EIGMETHMode extraction method to be used for the symmetric eigenvalue problem during the generation pass:
LANB | — | Block Lanczos algorithm (default). |
SUBS | — | Subspace algorithm. |
SNODE | — | Supernode algorithm. |
Issuing the CMSOPT command with no arguments
is invalid. You must specify at least the CMS method (CMSMETH) and the number of modes (NMODE). In a free-interface (CMSMETH = FREE)
or residual-flexible free-interface (CMSMETH = RFFB) CMS analysis, the default method for determining rigid body
modes is FAUTO (automatic).
CMS supports damping matrix reduction when a damping matrix
exists. Set the matrix generation key to 3 (SEOPT,Sename,SEMATR) to generate and then reduce stiffness, mass, and damping matrices.
CMS does not support the SEOPT,,,,,RESOLVE
command. Instead, ANSYS sets the expansion method for the expansion
pass (EXPMTH) to BACKSUB.
By default, the static constraint modes are not written to the
.CMS file for the fixed-interface and free-interface methods. Issue
IOKEY = CMS to write them.
If IOKEY = TCMS, the transformation matrix
is printed out and written to the .TCMS file when the
OUTPR command is issued with ITEM = NSOL and
FREQ not equal to NONE. In addition, the transformation matrix is
printed out when SEPR is equal to 1 or 2 on
SEOPT. In interactive sessions, the transformation matrix is not output
if the model has more than 10 elements.
For information about the component modes stored in the .CMS or .TCMS file, refer to Component Modes Storage.
If ELCALC = YES, the element results of
the static constraint modes and the fixed-interface normal modes are calculated and written to
the .CMS file. This can significantly reduce the computation time of the
CMS expansion pass. For limitations, see Calculating the Element Results.
For more information about performing a CMS analysis, see Component Mode Synthesis in the Substructuring Analysis Guide.
This command is also valid in /PREP7.