MODSELOPTION, dir1, dir2, dir3, dir4, dir5, dir6
Specifies the criteria for selecting the modes to be expanded.
dir1, dir2, …, dir6Selection of the direction to be expanded.
For ModeSelMethod=MODM on the MXPAND command, the directions correspond to the global
Cartesian directions, i.e. 1=X, 2=Y, 3=Z, 4=ROTX, 5=ROTY, and 6=ROTZ.
If dir1=YES, then any mode in this direction
is expanded if its modal mass divided by the total mass (modal mass
ratio) is greater than SIGNIF on the MXPAND command. If dir1=NO,
then the specified direction is not considered as a criterion for
expansion. If dir1 is given a numerical
decimal value, modes in that direction are selected (starting from
the ones with the largest modal mass ratios to the smallest) until
the sum of their modal mass ratio equals this requested threshold.
For ModeSelMethod=MODC on the MXPAND command, dir1 corresponds
to the first input spectrum, dir2 to the
second, etc. (i.e. for multiple spectrum inputs; the actual directions
correspond to their respective SED directions). If dir1=YES, then any mode in this spectrum is expanded if its mode coefficient
divided by the largest mode coefficient is greater than SIGNIF on
the MXPAND command. If dir1=NO, then the specified direction is not considered as a criterion
for expansion.
This command is only applicable when a mode selection method
is defined (ModeSelMethod on the MXPAND command). See Using Mode Selection in the Mechanical APDL Structural Analysis Guide for more
details.
If a numerical value is specified for a direction, the significance threshold (SIGNIF on the MXPAND command) is ignored for the selection of the modes in this direction.
If a mode is determined to be expanded in any of the 6 directions, it will be expanded in the .MODE file. Otherwise, the mode will not be expanded.
The default behavior is to consider all directions for expansion.