PARAM, MDTRKFLT

Bulk Data Entry Perform mode tracking.

Parameter Values Description
MDTRKFLT <0, 1, 2, 3 or 4>
0
Mode tracking is not performed for flutter analysis.
1
Performs mode tracking with the approach of eigenvalue-extrapolation for flutter analysis.
2 (Default)
Performs mode tracking with the approach of Normalized Cross Complex Orthogonality (NC2O) for flutter analysis.
3
Performs mode tracking with the approach of Modal Assurance Criteria in modal space (MMAC) for flutter analysis.
4
Performs mode tracking with the approach of Slope Continuity (SLCON) for flutter analysis.

Comments

  1. The mode tracking algorithms are only applicable to the flutter analysis using the PK method.
  2. There is no single mode tracking method with universal applicability across the entire spectrum of industrial flutter models. Different mode tracking options can be used, depending on the problem definition and your requirements. As a general guideline, the following order of mode tracking options is recommended: NC2O, MMAC, SLCON and eigenvalue-extrapolation.
  3. If mode switching is still observed after you try all the options provided by OptiStruct, it is suggested that you refine the velocities defined in the FLFACT card and rerun the model