LIMIT ON ITERATIONS REACHED

Hi,

I want to execute a topology optimization analysis for cantilever beam using stress constraint. i calculated the Bending stress of beam i got 3Mpa and in stress constraint i have given 2.70Mpa and also minmemb=10mm (mesh size given 10mm )

But I am getting this error.

LIMIT ON ITERATIONS REACHED.

INFEASIBLE DESIGN (AT LEAST ONE CONSTRAINT VIOLATED).

i have Activated the DesMax=30 and i tried for different iteration number but still same error

Can you tell me how why i am getting this error?

Thank you.

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Adriano Koga_20259

where i can define a new design constraint by defining 2.7Mpa. i mean in which panel or tool i have to use ?

1) create a response 'static stress' in the 'responses' panel, selecting the property where you want to compute stresses, and optionally, selecting elements to be 'exclude' from calculation

2) having your stress responses, go to 'dconstraints' panel, and select your stress response, and loadcase(s) desired, and then add an upper bound to it, just like any design constriant.

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Adriano Koga_20259

2 points here:

Number of iterations: are you sure you have checker the checkbox besides the DESMAX?

Stress constraint: this stress constraint inside the topology panel uses the legacy 'average' stress, that calculates the stress as an average of its surrounding neighborhood. So it is expected to have some values above the limit. But remember, topology optimization is a conceptual phase, so you don't really need to have it 100% respected from this phase. Also it applies globally, meaning that you cannot exclude elements such singularities and elements with BCs.

If you want more precise control, you might disable this option, and rather create a separated stress response in the 'responses' panel, and assign a design constraint to it, defining 2.7MPa. This will use p-norm and much more control over the stress values. But you will expect more time for running your model, as stress constraints bring much more mathematical complexity to your topology run. With this option you might exclude singularities and other non-physical regions from the stress evaluation.

Shabbik Shafiulla

2 points here:

Number of iterations: are you sure you have checker the checkbox besides the DESMAX?

Stress constraint: this stress constraint inside the topology panel uses the legacy 'average' stress, that calculates the stress as an average of its surrounding neighborhood. So it is expected to have some values above the limit. But remember, topology optimization is a conceptual phase, so you don't really need to have it 100% respected from this phase. Also it applies globally, meaning that you cannot exclude elements such singularities and elements with BCs.

If you want more precise control, you might disable this option, and rather create a separated stress response in the 'responses' panel, and assign a design constraint to it, defining 2.7MPa. This will use p-norm and much more control over the stress values. But you will expect more time for running your model, as stress constraints bring much more mathematical complexity to your topology run. With this option you might exclude singularities and other non-physical regions from the stress evaluation.

where i can define a new design constraint by defining 2.7Mpa. i mean in which panel or tool i have to use ?

Adriano Koga_20259

where i can define a new design constraint by defining 2.7Mpa. i mean in which panel or tool i have to use ?

1) create a response 'static stress' in the 'responses' panel, selecting the property where you want to compute stresses, and optionally, selecting elements to be 'exclude' from calculation

2) having your stress responses, go to 'dconstraints' panel, and select your stress response, and loadcase(s) desired, and then add an upper bound to it, just like any design constriant.

Shabbik Shafiulla

1) create a response 'static stress' in the 'responses' panel, selecting the property where you want to compute stresses, and optionally, selecting elements to be 'exclude' from calculation

2) having your stress responses, go to 'dconstraints' panel, and select your stress response, and loadcase(s) desired, and then add an upper bound to it, just like any design constriant.

thank you so much