I am running a topology optimisation (minimising Mass) and have included a stress constraint on the design variable using the parameter selection. Optistruct gives me a feasible solution, but when I look at the max Von Mises stress in the final iteration it is well above the upper bound I have specified for the stress constraint.
My problem requires plane symmetry and split draw but even without these additional factors the upper bound value does not appear to be constraining the stress
I get a similar result when I use Compliance as my objective function
Can anyone help??
For information:-
I have set up the model using the GUI, and the appropriate section of the *.fem file looks like
$HMNAME DESVARS 1DV1
DTPL 1 PSOLID 1
+ STRESS 4.37+8
and in the *.out file the 'Stress Constraints for Topology/Free-Sizing Optimization' is shown to be 'active' at each iteration
