# DRESP2

Bulk Data Entry 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 resulting from the design analysis iteration. Responses defined in this manner can be used as design objectives or constraints. The DRESP2 card identifies the equation to use for the response relationship and the input values to evaluate the response function.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DRESP2 ID LABEL EQID

or

FUNC
REGION
DRESPM RID1 MODELNAME1 RID2 MODELNAME2 RID3 MODELNAME3
RID4 MODELNAME4 etc etc etc etc
etc
VTYPE1 RID1 VOPT1 RID2 VOPT2 etc etc
etc
VTYPE2 RID1 VOPT1 RID2 VOPT2 etc etc
etc
VTYPEL1 RID1 LID1 VOPT1 RID2 LID2 VOPT2
etc
VTYPEL2 RID1 LID1 VOPT1 RID2 LID2 VOPT2
etc
VARTYPE1 ID1 ID2 ID3 ID4 ID5 ID6 ID7
ID8 etc etc
VARTYPE2 ID1 ID2 ID3 ID4 ID5 ID6 ID7
ID8 etc etc
etc etc etc etc etc etc etc etc

## Example 1

Define a response labeled FUNC1 that references equation #999, where DESVAR #11 is the first variable, the DTABLE entry PI is the second variable, DRESP1 #1 is the third variable, the Y location of grid #11 is the forth variable and the DVPREL1 #22 is the fifth variable.
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DRESP2 10 FUNC1 999
DESVAR 11
DTABLE PI
DRESP1 1
DGRID 11 2
DVPREL1 22

## Example 2

Define a response that is the weighted average of 2 displacements.
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DRESP2 3 AVDIS 7 2
DRESP1 9 2

## Associated Cards

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
DRESP1 9 TOPN DISP 1   3   4668
DRESP1 2 BOTN DISP 1   3   5432
DEQATN 7 y(x1, x2) = (x1*1.5+ x2*4.0)/2

## Definitions

Field Contents SI Unit Example
ID Response identification number. Each DRESP2 card must have a unique ID with respect to all other DRESP# cards.

No default (Integer > 0)

LABEL User defined name for the response. LABEL must begin with an alphabetical character.

No default (Character)

EQID DEQATN identifier that defines the response relationship.

No default (Integer > 0)

FUNC Function to be applied to the arguments. 13

No default (Character)

REGION Region identifier. 4

Default = blank (Integer > 0 or blank)

DRESPM Indicates the beginning of a continuation line, which defines model-specific response ID and Model Name pairs to be used in a Multi-Model Optimization run.
RID# Model specific responses identification numbers. 14

No default (Integer > 0)

MODEL NAME# User-defined model names defined on the ASSIGN, MMO entry. 14

No default (Character)

VTYPE# Variable type to follow.
DRESP1V
DRESP2V 16
DFREQ1V 17

No default (Character)

RID# Identification numbers of the corresponding response defined on the preceding VTYPE# fields.

No default (Integer > 0)

VOPT# Function type that is applied to the corresponding vector response specified via the preceding VTYPE# and RID# fields.
ATTI (Default)
Indicates that the vector is ATTI-based. For example, all grids listed on a DISP response would be passed as vector.
FREQ
Indicates that the vector is frequency-based. For example, the displacement of a given grid at all loading frequencies would be passed as vector. This is only meaningful for frequency response with blank ATTB.
ALL
Indicates that the vector is both ATTI-based and frequency-based. For example, all the internal responses spawned by the user-defined response would be passed as vector. Identical to ATTI for non-frequency response.
(Character)

VTYPEL# Variable type to follow.
DRESP1LV
DRESP2LV 16
DFREQ1LV 17

No default (Character)

LID# Subcase identification number for the corresponding response on the preceding RID# field.

No default (Integer ≥ 0)

VARTYPE# Variable type to follow. Can be one of: DESVAR, DTABLE, DGRID, DGRIDB, DGRIDL, DRESP1, DRESP1L, DRESP2, DRESP2L, DFREQ1, DFREQ1L, DVPREL1, DVPREL2, DVCREL1, DVCREL2, DVMREL1, DVMREL2, DVMBRL1, or DVMBRL2. 5 12 15 17

No default (Character)

ID# When VARTYPE is DESVAR, DTABLE, DRESP1, DRESP2, DFREQ1, DVPREL1, DVPREL2, DVCREL1, DVCREL2, DVMREL1, DVMREL2, DVMBRL1, or DVMBRL2 this list of IDs reference entities of the defined VARTYPE.

When VARTYPE is DGRID or DGRIDB, the list is a list of GRID/ID Component pairs, where every second value is a component (1, 2, or 3). For example, DGRID, 11, 2 indicates the Y component of grid 11. 12

When VARTYPE is DGRIDL, this list is a list of GRID, Component ID, and Coordinate system IDs, where every second value is a component (1, 2, or 3) and every third value is the coordinate system identification number. For example, DGRIDL, 11, 2, 1 indicates the Y component of grid 11 in a coordinate system of ID = 1. 12

When VARTYPE is DRESP1L, DRESP2L, or DFREQ1L, the list is a list of response/subcase pairs, where every second value is a subcase ID, for example, DRESP1L, 9, 1, 9, 3 indicates response 9 calculated for subcase 1 and response 9 calculated for subcase 3.

No default (Integer ≥ 0)

1. DRESP2 entries are referenced from the subcase through one of DESOBJ, DESSUB, or DESGLB.
2. DRESP2 entries must have unique identification numbers with respect to DRESP1 and DRESP3 entries.
3. DRESP1L, DRESP2L define a response defined with a DRESP1 or DRESP2, respectively, and a SUBCASE. The SUBCASE number 0 should be used for global responses. Similarly, DFREQ1L defines a corresponding DRESP1 response along with the SUBCASE ID to extract the loading frequencies associated with the DRESP1 response being referenced.
4. Responses with the same region identifier are grouped together into the same region. If the region identifier is blank, 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. For further information, refer to Constraint Screening in the User Guide.
5. Any number of VARTYPE# continuation lines can be defined. The order in which the VARTYPE# continuation lines are listed on the DRESP2 card is not specified. The same VARTYPE# can be repeated any number of times, in any position, on the card. However, the order in which the VARTYPE# continuation lines are listed will affect the solution as the values are passed to the equation (or function) in the listed sequence.
6. 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.
7. DRESPi and DRESPiL cards cannot be mixed on the same DRESP2 definition.
8. If DRESP1L, DRESP2L, DFREQ1L are used for a constrained DRESP2, DESGLB must be used to identify the DRESP2.
9. If DRESP1L, DRESP2L, DFREQ1L are used in a DRESP2 objective function, then the DESOBJ that references the DRESP2 must be defined before the first Subcase.
10. If the DRESP2 data is referenced by DESOBJ data, the DESOBJ data must be above the first SUBCASE if:
• The DRESP2 contains DRESP1L, DRESP2L, DFREQ1L data
• The DRESP2 contains no DRESP1, DRESP2, DRESP1L, DFREQ1L, or DRESP2L data
• The DRESP2 contains DRESP1, DRESP2 global responses

The DESOBJ data must be in the correct SUBCASE if the DRESP2 contains subcase dependent DRESP1 responses.

11. DRESP2 cannot reference itself directly or recursively, but multiple levels of referencing are allowed.
12. The DGRID and DGRIDB VARTYPE's can be used to select grid point locations as variables to be passed to the specified equation or function. The grid point locations are specified as a list of Grid point ID/Component pairs where every second value is a component. The Grid point ID's are unique grid point identification numbers (ID) and Components are the grid point locations X1, X2, and X3 fields on the GRID Bulk Data Entry.

DGRIDB:

The VARTYPE DGRIDB can be used to select grid point locations in the basic coordinate system. The basic coordinate system is the default rectangular coordinate system in OptiStruct.

DGRID:

The VARTYPE DGRID can be used to select the grid point locations in the local coordinate system of each grid point. This local coordinate system may be specified by the CP field of the GRID Bulk Data Entry for a particular grid point of interest. All local (or user-defined) coordinate systems are directly or indirectly based on the default basic coordinate system.

The VARTYPE DGRIDL can be used to select grid point locations as variables to be passed to the specified equation or function with respect to a user-defined coordinate system. The grid point locations are specified as a list of Grid point ID, Components, and Coordinate system IDs, where every second value is a component and ever third value is a user-defined coordinate system ID. The Grid point ID's are unique grid point identification numbers (ID) and Components are the grid point locations X1, X2, and X3 fields on the GRID Bulk Data Entries.

DGRIDL:

The VARTYPE DGRIDL can be used to select the grid point locations in a user-defined coordinate system for each component. This user-defined coordinate system may be specified as every third value. All local (or user-defined) coordinate systems are directly or indirectly based on the default basic coordinate system.

13. 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.
Function Description Formula
SUM Sum of arguments $\mathit{SUM}\left({y}_{1},{y}_{2}\dots {y}_{m}\right)=\sum _{j=1}^{m}{y}_{j}$
AVG Average of arguments $\mathit{AVG}\left({y}_{1},{y}_{2},\dots {y}_{m}\right)=\left[\sum _{j=1}^{m}{y}_{j}\right]/m$
SSQ Sum of square of arguments $\mathit{SSQ}\left({y}_{1},{y}_{2}\dots {y}_{m}\right)=\sum _{j=1}^{m}{y}_{j}^{2}$
RSS Square root of sum of squares of arguments $\mathit{RSS}\left({y}_{1},{y}_{2}\dots {y}_{m}\right)=\sqrt{\sum _{j=1}^{m}{y}_{j}^{2}}$
MAX Maximum of arguments
MIN Minimum of arguments
SUMABS Sum of absolute value of arguments $\mathit{SUM}\left({y}_{1},{y}_{2}\dots {y}_{m}\right)=\sum _{j=1}^{m}|{y}_{j}|$
AVGABS Average of absolute value of arguments $\mathit{AVG}\left({y}_{1},{y}_{2}\dots {y}_{m}\right)=\left[\sum _{j=1}^{m}|{y}_{j}|\right]/m$
MAXABS Maximum of absolute arguments
MINABS Minimum of absolute value of arguments
RMS Root mean square value of arguments $\mathit{RMS}\left({y}_{1},{y}_{2},\dots ,{y}_{m}\right)=\sqrt{\frac{1}{m}\left(\sum _{i=1}^{m}{y}_{i}^{2}\right)}$
14. Multiple RID-Model Name pairs can be specified on a single DRESPM continuation line. These responses can be used similar to responses defined via the VARTYPE# -ID# entries. ASSIGN, MMO can be used to identify the filename of the model and the user-defined Model Name that contains the referenced response definition.
15. An inconsistent number of responses can be referenced via multiple DRESP#L VARTYPE's. The following requirements should be met for such entries:
• A minimum of one DRESP# entry listed on a corresponding DRESP#L VARTYPE should reference only a single response value, (and)
• DRESP# entries listed on other DRESP#L VARTYPE's should reference the same number of responses.
• If requirement (1) above is not met, then the number of responses referenced by all the DRESP# entries (listed on all the DRESP#L VARTYPE's) should be equal.
Allowed Example:
DRESP1  1       R1      STRESS  ELEM       SVM3      1
2
DRESP1  2       R2      STRESS  PSHELL     SVM4      1
DRESP2  3       MA          1
+       DRESP1L        4   0
+       DRESP1L        2   2
DRESP1  4       vol       VOLUME
DEQATN  1       f(a,b)=a+b     
Not Allowed Example:
DRESP1  1       R1      STRESS  ELEM        SVM1      1
2
DRESP1  2       R2      STRESS  PSHELL      SVM2      1
DRESP2  3        MNA         1
+       DRESP1L        4   0
+       DRESP1L        1   2
+       DRESP1L        2   2
DRESP1  4       vol       VOLUME
DEQATN  1       f(a,b,c)=a+b+c                                             

In the Allowed example, the number of responses referenced by DRESP1L=4 is one. Also, DRESP1L=2 references multiple responses, this is allowed as there are no other DRESP#L that reference more than one response. However, in the "Not Allowed" example, DRESP1L=1 references two responses and DRESP1L=2 references multiple responses (this violates requirement 2 above).

16. The VTYPE#, RID#, and VOPT# fields can be used to identify the DRESP1 and DRESP2 responses to be passed as vectors to the DRESP2 entry. The VTYPEL#, RID#, LID#, and VOPT# fields can be used to identify the subcase-specific DRESP1 and DRESP2 responses to be passed as vectors to the DRESP2 entry.
17. The DFREQ1, DFREQ1L, DFREQ1V, and DFREQ1LV options are available to pass loading frequencies from a corresponding frequency-based DRESP1 response to the DRESP2/DRESP3. This is supported for Frequency Response and Random Response Optimization responses.
DFREQ1