MODSELOPTION

MODSELOPTION, dir1, dir2, dir3, dir4, dir5, dir6
Specifies the criteria for selecting the modes to be expanded.

SOLUTION: Dynamic Options

SOLUTION: Nonlinear Options

dir1, dir2, …, dir6

Selection of the direction to be expanded.

For ModeSelMethod = EFFM 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 effective mass divided by the total mass (modal effective 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 effective mass ratios to the smallest) until the sum of their modal effective 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.

Notes

This command is only applicable when a mode selection method is defined (ModeSelMethod on the MXPAND command). See Using Mode Selection in the 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.

For ModeSelMethod = EFFM on the MXPAND command, dir4, dir5, and dir6 are not considered if mass related information have been calculated using the lumped approximation instead of the precise calculation (See Mass Related Information in the Theory Reference).

Menu Paths

This command cannot be accessed from a menu.