There are three types of responses in OptiStruct. The first are analysis results, the second are combinations of analysis results, design variables, constants (defined using a DTABLE card), grid locations, and property relations, and the third are external responses. The first type are defined using the DRESP1 card, the second using the DRESP2 card (which in turn references a DEQATN card), and the third using the DRESP3 card, which in turn references a LOADLIB external library reference. A description of the analysis results that may be used as responses is found in the Responses section of the User's Guide. Responses are required to define constraints and objectives, or they can be used for monitoring purposes. Below are examples of response definitions.
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Example: Design Response 1 - references frequency of 1st mode. |
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(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
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DRESP1 |
1 |
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FREQ |
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1 |
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Example: Design Response 10 - references equation 999 with DESVAR 11, the 3rd DTABLE entry, DRESP1 1, DVPREL1 22. (The order of the variables on the DEQATN card must match the order in which the variables are listed on the DRESP2 card. i.e. DESVAR 11 is the 1st variable listed on the left-hand side of DEQATN 999, the 3rd DTABLE entry is the 2nd variable listed on the left-hand side of DEQATN 999, etc.). |
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(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
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DRESP2 |
10 |
Sum |
999 |
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DESVAR |
11 |
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DTABLE |
3 |
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DRESP1 |
1 |
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+ |
DVPREL1 |
22 |
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Example: Design Equation 999 - Sum of four variables. |
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(1) |
(2) |
(3) |
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DEQATN |
999 |
F(A,B,C,D) = A + B + C + D |
Note: A DRESP# card cannot have the same ID number as any other DRESP# card.