SDAMPING

Subcase Information Entry Used to apply modal damping as a function of natural frequency in modal solutions.

Format

SDAMPING(type) = option

Definitions

Argument Options Description
type <STRUCTURE, FLUID> The referenced Bulk Data Entry is applied to:
STRUCTURE (Default)
Structural portion of the model.
FLUID
Fluid portion of the model.
option <SID>

No default
SID
Identification number of a TABDMP1 or TABDMP2 Bulk Data Entry.

Comments

  1. SDAMPING can only be used in Modal Transient, Modal Frequency Response Analysis, and Modal Complex Eigenvalue Analysis; and must reference a TABDMP1 or TABDMP2 Bulk Data Entry.
  2. Only one SDAMPING entry of each type can be defined for each subcase.
  3. If present above the first subcase, it is applied to each modal frequency or modal transient subcase without an SDAMPING entry.
  4. To achieve identical displacements in Modal frequency response or Modal transient analyses when the SDAMPING is used instead of PARAM, G, the steps described here can be followed:
    • The TYPE field in the TABDMP1 or TABDMP2 Bulk Data Entry should be set to CRIT.
    • Set the damping value (field gi ) in the TABDMP1 or TABDMP2 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