Crushable foam material in optistruct

Altair Forum User

Hi, 

I am trying to model expanded polypropylene material and i am trying to figure out what material Id and property type we must use in optistruct. 

 

Thanks 

Altair Forum User

Hi Adithya,

 

What is the analysis about?

 

You can use MATX33, MATX70 

 

Or use RADIOSS with LAW33, LAW 70

Altair Forum User

Hi, Thank you for your response.

It is a non linear quasi static analysis on the seat. I am using EPP material for the foam.

 

Altair Forum User

Hi @Adithya

 

I suggest you use RADIOSS for such a problem.

Altair Forum User

I need to further optimize the design, thats why i am modelling it with optistruct, right now, I tried converting from optistruct to radioss but i am missing 1d elements which were placed on the components. I am using the latest version of 2017.2

Altair Forum User

Hi @Adithya

 

What type of Optimization are you planning to do?

 

RADIOSS does supports optimization starting from 2017. Please refer to this example problem of thickness optimization on a B-pillar

RD-E: 5100 Optimization in RADIOSS for B-Pillar (Thickness optimization)

Altair Forum User

Hi,

Its a composite material, and i would need to perform and try all the 3steps available in optistruct. Btw my analysis is taking very long time to run, this has been the case ever since i gave tie connection between a solid element and shell element, is there a more less time consuming way to solve this? because before having the solid elements and connections, it took lesser time to compute, will a 1D connection with rigid element solve the issue? Also i am not facing any issues in optistruct with the file, I am using NLGEOM as i have a foam material.

Altair Forum User

• I tried with 1d connections as well, it doesnt seem to work. For nlstat the same amount of element and connections, the results are getting computed faster, i think it has to do with something in Nlelast type.

Altair Forum User

Hi @Adithya

 

Is it possible to share the model file, please?

Please use the file transfer link in my signature to share the model file
 

Altair Forum User

Hi, I have attached the file in the file transfer link

 

Thank you.

Altair Forum User

Hi @Adithya

 

I didn't receive any file at my end. 

Altair Forum User

Hmm, that is strange. I have sent you the file again. Please check

 

Thank you.

Altair Forum User

@Adithya

 

I got the files. thank you

 

I see that you are running a linear static analysis.

 

Altair Forum User

Hi no, I am running a nonlinear geometric analysis.

Altair Forum User

Hi @Adithya

 

OK, It is NLGEOM and I am running the file right now. 

 

One way to increase the speed of the analysis is to use a coarser mesh instead of a finer mesh. 

Altair Forum User

 

Hi Prakash

Oh great, Is it taking too long or did you get any results?

Thank you.