DRESP2

Bulk Data Entry

DRESP2 – Design Response via Equations for Design Optimization

Description

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	MODEL NAME1	RID2	MODEL NAME2	...	...
	VTYPE1	RID1	VOPT1	RID2	VOPT2	...	...
		...
	VTYPE2	RID1	VOPT1	RID2	VOPT2	...	...
		...
	VTYPEL1	RID1	LID1	VOPT1	RID2	LID2	VOPT2
		...
	VTYPEL2	RID1	LID1	VOPT1	RID2	LID2	VOPT2
		...
	VARTYPE1	ID1	ID2	ID3	ID4	ID5	ID6	ID7
		ID8	...	...
	VARTYPE2	ID1	ID2	ID3	ID4	ID5	ID6	ID7
		ID8	...	...
	...	...	...	...	...	...	...	...

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

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) = (x11.5+ x24.0)/2

Field	Contents
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 (Comment 13). No default (Character)
REGION	Region identifier (Comment 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 (Comment 14). No default (Integer > 0)
MODEL NAME#	User-defined model names defined on the ASSIGN, MMO entry (Comment 14). No default (Character)
VTYPE#	Indicates the type of variables to follow. Can be either DRESP1V or DRESP2V (Comment 16). No default (Character)
RID#	Identification numbers of the corresponding response defined on the preceding VTYPE# fields. No default (Integer > 0)
VOPT#	The function type that is applied to the corresponding vector response specified via the preceding VTYPE# and RID# fields. Can be either ATTI, FREQ, or ALL. 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. Default = ATTI (Character)
VTYPEL#	Indicates the type of variables to follow. Can be either DRESP1LV or DRESP2LV (Comment 16). No default (Character)
LID#	Subcase identification number for the corresponding response on the preceding RID# field. No default (Integer > 0)
VARTYPE#	Indicates the type of variables to follow. Can be one of: DESVAR, DTABLE, DGRID, DGRIDB, DGRIDL, DRESP1, DRESP1L, DRESP2, DRESP2L, DVPREL1, DVPREL2, DVCREL1, DVCREL2, DVMREL1, DVMREL2, DVMBRL1, or DVMBRL2 (Comments 5, 12 and 15). No default (Character)
ID#	When VARTYPE is DESVAR, DTABLE, DRESP1, DRESP2, 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 (Comment 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 (Comment 12). When VARTYPE is DRESP1L or DRESP2L, 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)

Comments

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.

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's Guide.

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 are used for a constrained DRESP2, DESGLB must be used to identify the DRESP2.

9.	If DRESP1L, DRESP2L 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 data

•	The DRESP2 contains no DRESP1, DRESP2, DRESP1L, 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.

Examples:

dresp2_dgrid

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.

Example:

dresp2_dgridl

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
AVG	Average of arguments
SSQ	Sum of square of arguments
RSS	Square root of sum of squares of arguments
MAX	Maximum of arguments
MIN	Minimum of arguments
SUMABS	Sum of absolute value of arguments
AVGABS	Average of absolute value of arguments
MAXABS	Maximum of absolute arguments
MINABS	Minimum of absolute value of arguments
RMS	Root mean square value of arguments

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)	A minimum of one DRESP# entry listed on a corresponding DRESP#L VARTYPE should reference only a single response value, (and)

b)	DRESP# entries listed on other DRESP#L VARTYPE’s should reference the same number of responses.

c)	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.

Example

Allowed

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

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 above example (Allowed), 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.	This card is represented as optimization responses in HyperMesh.