DMPSTR

DMPSTR, COEFF, DMPSFreqTab
Sets constant structural damping data.

SOLUTION: Dynamic Options

COEFF: Constant structural damping coefficient.
DMPSFreqTab: Average excitation frequency table (Hz) for the calculation of equivalent viscous damping from structural damping input (DMPSTR and MP,DMPS) in a full transient analysis. Enclose the table name in percent signs (%) and use the *DIM command to define the table with primary variable TIME. To define a constant frequency instead of a table, see TRNOPT.

Command Default

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

Notes

Sets a constant structural (or hysteretic) damping coefficient for use in these analysis types:

Harmonic (ANTYPE,HARMIC) -- full, Krylov, or mode-superposition [1]
Modal (ANTYPE,MODAL) with MODOPT,UNSYM, DAMP, or QRDAMP.

In a mode-superposition harmonic or transient analysis, you must apply the load in the modal portion of the analysis. Mechanical APDL calculates a load vector and writes it to the MODE file, which you can apply via the LVSCALE command.

DMPSTR is also supported in transient (ANTYPE,TRANS) analyses (full or QRDAMP mode-superposition) as an equivalent viscous damping when an average excitation frequency is specified. For a full or mode-superposition transient, specify a constant excitation frequency as DMPSFreq on the TRNOPT command. For a full transient, you can alternatively specify a table of frequencies using DMPSFreqTab on this command. DMPSFreqTab overwrites DMPSFreq on TRNOPT.

Note that for structures with multiple materials, MP,DMPS can also be used to specify constant structural material damping on a per material basis. If both DMPSTR and MP,DMPS are specified, the damping effects are additive.

This command is also valid in PREP7.

Menu Paths

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

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