PARAM, MODETRAK

Parameter

Values

Description

MODETRAK

<-1, 0, 1, YES, NO>

Default = NO

If -1, 0 or NO, mode tracking is not used. Mode numbers are determined by frequency.

If 1 or YES, mode tracking is used. Mode numbers are tracked by comparing eigenvectors between iterations.

Concerning mode tracking, the following symbols are used in the output format:

Indicates that the tracked mode was not found in the modes retrieved for that iteration. If this mode is not a part of the objective, optimization will continue and mode will be tracked if found in later iterations, otherwise optimization will stop. If optimization is halted for this reason, increase the number of modes or range of modes being retrieved.

~	Indicates that the tracked mode was found but does not correlate well with the original mode. Optimization will continue.

Notes:

In topology optimization, mode shapes can change greatly due to the reorganization of material within the design domain. For some models, mode tracking may be of limited effectiveness. Also, the values of optimized modes may increase substantially during the optimization process. You are advised to provide a wide range or large number of modes in the EIGRL card to protect against optimized modes being lost.

2.	This parameter is ignored if a MODTRAK subcase information entry is present in the input.