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DRESP3 in Optistruct

DRESP3 in Optistruct

DRESP3 in Optistruct

(OP)
Hi

I am trying to combine constraints in a size optimisation in Optistruct. I have tried it in various ways and get similar errors (but no results sad).

i) If I use dequations and normalise the displacement constraint and stress constraint so that they have the same range and then use a 3rd equation to combine them I get the error
number of responses in DRESP2 inconsistent

ii) if I normalise the constraints in Optistruct but then try to send them to HyperMath for constraint aggregation using a DRESP3 card. I get a similar error to the above but for DRESP3.

iii) If I used DRESP2L in the DRESP3 card with each response paired with a suitable subcase I get the error that DRESP3 statement is not referenced above the first subcase, but I don't know what to do with that - all the obvious moving of statements doesn't seem to make any difference.

Anyone got any thoughts? btw I am using Optistruct 11.0

Cheers

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