Composite size optimization / Composite failure

Dear all,

I am trying to run a composite size optimization. I want to find the optimal thickness of each ply I have created in my laminate.

My model consists in shell elements. I only have created one laminate that have multiple plies.

I want to optimize each ply thickness. I tried with the 'ply thickness' and PTMIN and PTMAN but did not work (minimize mass subjected to displacement). No iterations are run and it just gives me the results of a normal FEM analysis. Any idea why? Or how should I do it?

Second question..I inserted the control card 'global output request' CSTRESS CSTRAIN CFAILURE. The first two work fine, but I can not see the results of Composite Failure after the FEM analysis. It just gives me all value of 1.

Any suggestion on how I can see the failure results of the composite?

Thank you very much!!!!

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Altair Forum User

Hi Mike,

For 1st question, can you if Optimization is turned ON in OptiStruct panel under run options (see the image)?

<?xml version="1.0" encoding="UTF-8"?>

For 2nd question, please check whether failure criteria is provided in property card or not. A valid failure criteria is necessary to calculate failure index and strength ratios like TSAIWU, etc...

Altair Forum User

Hi Prakash,

How do I provide failure criteria in the property card?

For first question..yes I do that. But I don't understand why is not working.

Is correct the procedure? I create a laminate with different ply. How is the best way to optimize the thickness of each global ply (and not of each element)?

Thank you a lot for your answer

Altair Forum User

Hi Prakash,

I have attached the images of my panel and of the design variable I created in 'Composite Size'.

Does it look correct?

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi,

You can specify failure criteria in PCOMPP>>FT. You will see a selection menu where different failure criteria are listed. Select your choice and try.

Altair Forum User

Hi Prakash,

Yes thank you I have find that.

Any idea for the optimization??

Altair Forum User

Hi Mike,

DId you change the analysis option in OptiStruct panel to Optimization?

If possible, can you share the .out file?

Altair Forum User

Yes I did. The .out file says that no design variables are found.

no-optimization-running.JPG.a3d8f3c57580c454665ca5bb826f3309.JPG

Altair Forum User

Mike,

Can you share the model file using Filetransfer link in my signature?

Altair Forum User

Yes done it!

Thank you for your time!!!

Altair Forum User

Hi Mike,

I see you have created Design variable for laminate and not for plys.

Goto Size panel in optimization page and create design variables for plys and try again

Altair Forum User

Hi Prakash,

Thank you for your answer.

So in 'Composite Size' I have to select PCOMP as type and not STACK?

I have a PCOMPP card right now. I can not set this property in the PCOMP type.

Can I run it using ply based composite?

Altair Forum User

Mike,

What you did is not wrong. But apart from that you need to defines plies as design variables.

Right now what you have is plies and laminate which is a ply based model and it is perfectly fine.

Faisal

Mike,

What you did is not wrong. But apart from that you need to defines plies as design variables.

Right now what you have is plies and laminate which is a ply based model and it is perfectly fine.

Hello,

I am getting the same issue i have a model in which the plies are already created so i want to skip the free size optimization and would like to do directly size optimization. I am not sure how to start second step directly. What i have to give in the design variable? I have tried but it says No design material or design variable found. analysis only

If you have any idea please help me out.