Composite modeling Size optimization

Altair Forum User

Hi everyone,

I m making a composite size optimization and need to use the same design variable to multiple plies.

Simplified, I need several different plies to have the same thickness and I need several plies with diferent thickness aswell.

I formulated the problem this way and create a generic relationship to each ply, using only one design variable for multiple plies. This didn't work and appeared an error.

 

I checked the dlink card but I dont know if that fits my purpose because how can I link DVs in order to have the same value?

Any ideia on how can I do this?

 

Best regards,

Gonçalo

 

 

Altair Forum User

Hi @GonPer

 

So you have created a DV for a ply and linked this DV to other plies DV, is my understanding correct?

 

Can you share the error message or .out file?

Altair Forum User

Hi Prakash,

Thank you for your fast answer.

The error is:

 *** ERROR # 532 ***
 Independent DESVAR -2 on DLINK 6 is also declared
 dependent on DLINK -2.

 

I created 20 DV. I have 116 plies and made the generic relationship to each ply, linking it to a DV. Each DV has multiple plies linked to it via the generic relationship.

Didn't link DV to DV, linked multiple DVPREL to a DV.

 

best regards,

Gonçalo

Altair Forum User

Also I dont have any DLINK card defined. I guess the error says DLINK maybe because the DVPREL uses a DLINK to connect to DV?

 

Gonçalo

Altair Forum User

Hi @GonPer

 

Yes,

 

The error message says the same DESVAR is used on two DLINKS as independent and dependent DESVAR but I am confused with the DLINK ID -2. 

 

I will check with experts and will let you know the solution soon. 

Altair Forum User

@GonPer

 

Do you have Ply balance constraint on your laminate?

 

If yes can you remove the same and try again?

Altair Forum User

Hi Prakash,

 

Yes I had it on. But it isn't necessary because all the 45, -45 plies are connected in the same desvar.

Another thing that did not make sense, was that the numbers on desvars and dlinks in the error were not the same as I defined.

 

So far is runing without problems.

Thank you very much, I tought that one week of work went down the toilet, but fortunetly no.

 

Best regards,

Gonçalo

 

 

 

Altair Forum User

Altair Forum User said:

Another thing that did not make sense, was that the numbers on desvars and dlinks in the error were not the same as I defined.

 

@GonPer

 

Good to know that you are able to see some progress.. /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20'>

 

Altair Forum User said:

Another thing that did not make sense, was that the numbers on desvars and dlinks in the error were not the same as I defined.

 

Yes, this looks like a defect which I am going to let Devs know about it so that they can sort this out ASAP!!! 

Altair Forum User

Hi Prakash,

Thank you for your help.

Just another thing, I dont know why but the SZTOSH option, produced a .fem file that is all changed up.

Different orientations in plies, lost ply systems, different element sets in the plies. So it isn't usable.

When I used this option with simple models it worked ok, I dont know why it didn't work this way.

 

I will do it by hand, but just for information I think you should let the Devs know aswell so they can improve it.

 

Best regards,

Gonçalo

Altair Forum User

Hi @GonPer

 

Thank you for letting us know. There was a bug in S/w using othrotropic material and our Devs are already working on it. 

 

I will keep you posted on the same if there is any update from Dev team.