DSYSID

Bulk Data Entry Defines responses and their target values for a system identification problem.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DSYSID DOID LABEL RID1 SID1 T1

/TID1

W1

/WTID1

+ RID2 SID2 T2

/TID2

W2

/WTID2

+ etc
+ RIDi SIDi Ti

/TIDi

Wi

/WTIDi

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DSYSID 22 SYS 3 4 0.002
+ 5 5 0.05

Associated Cards

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DRESP1 3 TZ488 DISP 3 488
DRESP1 5 TZ601 DISP 3 601

Definitions

Field Contents SI Unit Example
DOID Design objective identification number.

(Integer > 0)

LABEL User-defined name for the response.

No default (Character)

RIDi DRESP1, DRESP2, or DRESP3 identification number.

(Integer > 0)

SIDi Subcase identification number.
ALL (Default)
If it applies to all subcases.
blank

(Integer > 0)

Ti/TIDi Target value or table identification number of a TABLEDi entry that specifies the target value as function of a loading frequency.

No default (Real or Integer)

Wi/WTIDi Weighting factor or table identification number of a TABLEDi entry that specifies the weighting factor as function of a loading frequency.

Default = 1.0 (Real, Integer or blank)

Comments

  1. If the DSYSID entry is referenced by a DESOBJ Subcase entry, a least squares objective function is used in the optimization. The objective function is the sum of the squared, weighted, normalized differences between the target responses and those calculated by the finite element analysis:
    min i = 1 n ( W i F i T i T i ) 2
    If the DSYSID entry is referenced by a MINMAX or MAXMIN Subcase Information Entry, the beta method is applied in the optimization as:
    min β with W i | F i T i T i | β
  2. DSYSID entries must have unique identification numbers with respect to DRESP1, DRESP2, and DRESP3 entries.
  3. DRESP1, DRESP2, and DRESP3 entries referenced by the DSYSID entry can define only a single response per subcase when the DESOBJ formulation is used. There is no such limitation with the MINMAX or MAXMIN formulations.
  4. In order to use DSCREEN to control the number of retained responses when performing a system identification, RTYPE=EQUA needs to be used on the DSCREEN entry.