Fatigue optimization with dynamic pressure

mabefa

Hi,

I would like to do an optimization with a constraint on fatigue life of a component.

The problem is that I don't have a concentrated  load with his load history but I have a dynamic pressure which I imported with two csv file. In both of this files I have the coordinates of the points where the pressures are applied, in the first I have the real part of this dynamic pressure and in the second I have the immaginary part.

Then I created a loadstep with card freq.resp.(direct) in which I selected as DLOAD the loadcollector I created to include the real part and the immaginary part of the dynamic pressure and in FREQ I selected the load collector that I created to determinate the range of frequency I want to study.

Now I would like to do an optimization trying to maximize the percentage of volume to remove but I would like to have a constraint on fatigue life.

So I created a response with card fatigue and I've gone in dconstraint. I selected lower bound and wrote 20000 and selected as response the response fatigue that I created before.

The problem is that when I select the loadstep and then create the dconstraint the software gives me an error saying that the loadstep is not compatible with the type of resonse.

How can I resolve this problem?

Altair Forum User

Hi @mabefa

 

I think frequency response is not allowed for fatigue.

 

You can use Transient or Random response analysis type, instead.

mabefa

I tried both of them but none is compatible with the fatigue reponse.

Altair Forum User

Hi @mabefa

 

You should have a fatigue subcase to use fatigue responses for optimization. If you are using FRA subcase with fatigue response, this will not work.

 

Please check the same and try again.