DRESP2 – Design Response via equations for design optimization
When a desired response is not directly available from OptiStruct, it may be calculated using DRESP2. This response can be a functional combination of any set of responses that are the result of a design analysis iteration. These responses can be used as a design objective or as design constraints. The DRESP2 card identifies the equation to use for the response relationship and the input values to evaluate the response function. DRESP1 and DRESP1L cards cannot both exist in a DRESP2 definition.
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(7) |
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(9) |
(10) |
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DRESP2 |
ID |
LABEL |
EQID |
REGION |
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DESVAR |
DVID1 |
DVID2 |
DVDID3 |
DVDID4 |
DVDID5 |
DVDID6 |
DVDID7 |
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DVDID8 |
… |
… |
… |
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DTABLE |
LABL1 |
LABL2 |
LABL3 |
LABL4 |
LABL5 |
LABL6 |
LABL7 |
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LABL8 |
… |
… |
… |
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DRESP1 |
NR1 |
NR2 |
NR3 |
NR4 |
NR5 |
NR6 |
NR7 |
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NR8 |
… |
… |
… |
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DRESP1L |
NR1 |
LIDR1 |
NR2 |
LIDR2 |
NR3 |
LIDR3 |
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NR4 |
LIDR4 |
… |
… |
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DGRID |
G1 |
C1 |
G2 |
C2 |
G3 |
C3 |
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G4 |
C4 |
… |
… |
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DVPREL1 |
DPIP1 |
DPIP2 |
DPIP3 |
DPIP4 |
DPIP5 |
DPIP6 |
DPIP7 |
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DPIP8 |
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DRESP2, 10, Sum, 999 |
$ Response #10 references equation #999 |
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+, DESVAR, 11 |
$ DESVAR #11 is the first variable in equation #999 |
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+, DTABLE, PI |
$ Value of DTABLE entry PI is the second variable in equation #999 |
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+, DRESP1, 1 |
$ DRESP1 #1 is the third variable in equation #999 |
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+, DGRID, 11, 2 |
$ Y location of grid #11 |
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+, DVPREL1, 22 |
$ DVPREL1 #22 is the fourth variable in equation #999 |
Example 2 Define a response that is the weighted average of 2 displacements
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(3) |
(4) |
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(10) |
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DRESP2 |
3 |
AVDIS |
7 |
2 |
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DRESP1 |
9 |
2 |
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(9) |
(10) |
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DRESP1 |
9 |
TOPN |
DISP |
1 |
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3 |
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4668 |
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DRESP1 |
2 |
BOTN |
DISP |
1 |
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3 |
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5432 |
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DEQATN |
7 |
y(x1, x2) = (x1*1.5+ x2*4.0)/2 |
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Field |
Contents |
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ID |
Response identity Each DRESP2 card must have a unique ID. (Unique integer > 0) |
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LABEL |
User defined name for the response. (Character) |
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EQID |
DEQATN identifier that defines the response relationship. (Integer > 0) |
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FUNC |
Function to be applied to the arguments. See comment 14. (Character) |
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Region |
Region identifier. See comment 4. (Integer > 0 or blank) |
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DESVAR |
DESVAR flag indicating DESVAR ID numbers follow. |
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DVIDi |
DESVAR IDs. (Integer > 0) |
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DTABLE |
DTABLE flag indicating DTABLE label numbers follow. |
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LABLi |
Constant label in DTABLE data. (Character) |
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DRESP1 |
DRESP1 flag indicating DRESP1 ID numbers follow. |
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Nri |
DRESP1 IDs. See comment 11. (Integer > 0) |
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DRESP1L |
DRESP1L flag indicating DRESP1 ID numbers and SUBCASE IDs follow. |
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LIDRi |
SUBCASE IDs. (Integer > 0) |
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DVPREL1 |
DVPREL1 flag indicating DVPREL1 ID numbers follow. |
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DPIPi |
DVPREL1 IDs. (Integer > 0) |
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DGRID |
DGRID flag indicating Grid ID numbers and components follow. |
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Gi |
Grid IDs. (Integer > 0) |
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Ci |
Component IDs (1, 2, or 3). |
DRESP1 entries reference responses in the subcase defined by the associated DESOBJ, DESSUB, or DESGBL.
DRESP2 entries must have unique identification numbers with respect to DRESP1 and DRESP3 entries.
DRESP1L defines a response defined with a DRESP1 and a SUBCASE. The SUBCASE number 0 should be used for global responses.
Responses with the same region identifier are grouped together into the same region. If the region identifier is blank or 0, then a separate region is formed for each DRESP2 definition. The RTYPE EQUA on the DSCREEN definition refers to DRESP2 responses. It is important to ensure that responses with the same region identifier reference similar equations. Please read the User's Guide section Constraint Screening for a more detailed explanation.
The DESVAR/DTABLE/DRESP1(L)/DGRID/DVPREL1 cards must be defined in the order shown. Any card may be deleted if not required but at least one must exist.
The entries on the DRESP2 cards are assigned to the variable on the DEQATN card in the order that they occur. For example 2 above x1 is the displacement response defined by the DRESP1 card with ID=9 and x2 is the displacement response defined by the DRESP1 card with ID=2.
DRESP1 and DRESP1L cards cannot both exist in one DRESP2 definition.
If DRESP1L is used for a constrained DRESP2, DESGLB must be used to identify the DRESP2.
If DRESP1L is used in a DRESP2 objective function, then the DESOBJ that references the DRESP2 must be defined before the first Subcase.
If the DRESP2 data is referenced by DESOBJ data, the DESOBJ data must be above the first SUBCASE if; 1) the DRESP2 contains DRESP1L data, 2) the DRESP2 contains no DRESP1 or DRESP1L data or, 3) the DRESP2 contains DRESP1 global responses. The DESOBJ data must be in the correct static or eigenvalue SUBCASE if the DRESP2 contains static or eigenvalue DRESP1 responses.
DRESP1 of RTYPE = WCOMP, WFREQ, COMB, and BEADFRAC cannot be referenced by DRESP2 data.
DRESP1 of RTYPE = MASS, VOLUME, and COMP that uses ATTB = SUM cannot be referenced by DRESP2 data.
LABEL must begin with an alphabetical character.
The following functions can be used instead of an EQID. If FUNC is used, the DEQATN entry is no longer needed. The functions are applied to all arguments on the DRESP2 regardless of their type.
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Function |
Description |
Formula |
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SUM |
Sum of arguments |
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AVG |
Average of arguments |
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SSQ |
Sum of square of arguments |
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RSS |
Square root of sum of squares of arguments |
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MAX |
Maximum of arguments |
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MIN |
Minimum of arguments |
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SUMABS |
Sum of absolute value of arguments |
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AVGABS |
Average of absolute value of arguments |
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MAXABS |
Maximum of absolute arguments |
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MINABS |
Minimum of absolute value of arguments |
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Go To
Guidelines for Bulk Data Entries
Alphabetical List of Bulk Data Entries