Design Optimization issues

[francesco87]

Hi everyone!

I'm facing two problems with the Design Optimization tool of Femap 10.2 with NX Nastran, namely:

- when optimizing rods subject to compressive loading (therefore producing negative axial stresses), the solver fails if I set a negative value for the design constraint (for example, axial stress from -10 Mpa to 0 Mpa). On the other hand, if I set a positive value (from 0 to 10 Mpa), the solver works but the value of the initial constraint differs from the one resulting from the static analysis; for example, if the static analysis gives a compressive axial stress of -5 MPa, the function "MAX VALUE OF CONSTRAINT" resulting from the design optimization starts from a value of +5000MPa! Always the same value but 1000 times more!

- when optimizing plates, the solver ends up with USER FATAL MESSAGE 4298 and USER FATAL MESSAGE 9069.

Thanks in advance!

 

[francesco87]

I have fixed the second bug, but I still encounter the first one, and not only for rods. More in general, I get disagreement between the function "MAX VALUE OF CONSTRAINT" (provided by the design optimization analysis) and the actual stress acting on the structure (obtained from a preliminar static analysis).

 

[FEMAP2]

Can you send the problem model to us, the FEMAP Development Team, we would be glad to take a look at it.

Mark

sherman dot mark at siemens dot com