SDAMPING

Subcase Information Entry

SDAMPING - Data Selection

Description

The SDAMPING command can be used in the Subcase Information section to apply modal damping as a function of natural frequency in modal solutions.

Format

SDAMPING (type) = option

Argument

Options

Description

type

< STRUCTURE, FLUID >
Default = STRUCTURE

The referenced bulk data entry is applied to the structural (STRUCTURE) or fluid (FLUID) portion of the model.

option

< SID >

No default

SID: Set identification of a TABDMP1 bulk data entry.

1.	SDAMPING can only be used in modal transient, modal frequency response and modal complex eigenvalue analyses; and must reference a TABDMP1 bulk data entry.

2.	Only one SDAMPING entry of each type can be defined for each subcase.

3.	If only one type of SDAMPING entry is defined (either SDAMPING(STRUCTURE) or SDAMPING(FLUID)), this definition will be used for both the structure and the fluid portion of the model.

4.	If present above the first subcase, it is applied to each modal frequency or modal transient subcase without an SDAMPING entry.

5.	To achieve identical displacements in Modal frequency response or Modal transient analyses when the SDAMPING bulk data entry is used instead of PARAM, G, the steps described here can be followed:

•	The TYPE field in the TABDMP1 bulk data entry should be set to CRIT. This TABDMP1 bulk data entry is referenced by the SDAMPING subcase information entry.

•	Set the damping value (field gi) in the TABDMP1 bulk data entry equal to half of the value of PARAM, G (that is set the constant value to C/C0).

•	Set PARAM, KDAMP,-1