DMPRAT

DMPRAT, RATIO
Sets a modal damping ratio.

SOLUTION: Dynamic Options

RATIO: Modal damping ratio (for example, 2% is input as 0.02).

Command Default

Use damping as defined by Damping in the Structural Analysis Guide.

Notes

Sets a damping ratio for use in a mode-superposition transient analysis (ANTYPE,TRANS with TRNOPT,MSUP), a mode-superposition harmonic analysis (ANTYPE,HARMIC with HROPT,MSUP) analysis, or a spectrum (ANTYPE,SPECTR) analysis.

DMPRAT can also be defined in a substructure analysis that uses component mode synthesis. The damping ratio is added on the diagonal of the reduced damping matrix, as explained in Component Mode Synthesis (CMS).

This command is also valid in PREP7.

Additional Information

Damping Matrices in the Mechanical APDL Theory Reference.

Menu Paths

Main Menu>Preprocessor>Loads>Load Step Opts>Time/Frequenc>Damping

Main Menu>Solution>Load Step Opts>Time/Frequenc>Damping