"Skin" results output for solid elements

timonq

Hi!

I'm calculating big models containing solid elements and I would like to reduce size of my results file by saving only values for boundary skin. I use this technique in other solver and it works fine. 

My question is: it is possible to set some parameter or card to do this in Optistruct?

 

Thank you in advance 

Q.Nguyen-Dai

With SAMCEF solver, I use membrane element cover solid elements to capture surface stress. These membrane elements have the same material as solid but with very small thickness (about 1.0E-05 mm).

I think you can do the same with Optistruct, but you need define something within shell card to make them like a membrane.

Altair Forum User

Hi,

 

You can use extract faces and assign PSHELL card 

Q.Nguyen-Dai

Altair Forum User said:

Hi,

 

You can use extract faces and assign PSHELL card 

Really? No need to set something 'special' to shell card?

Altair Forum User

HI,

 

While defining the PSHELL properties for the skin elements, you should define only the membrane properties and not the Bending and Transverse shear properties. So MID1 should be enough. 
 The thickness of the skin elements needs to be small. So, a thickness of 0.01 should be fine. Specifically, I am not aware on any thickness ranges for the skin elements.

timonq

Hi, could you tell me how should I write command to output results only for membrane? For example: STRESS(,H3D,,,CORNER,,,,) = SID. What kind of set is SID? 

 

tinh

SID is element set , I think

enter analysis>entity set to create a set of elements you want to export.

timonq

Thanks, I prepare sets (nset for displacement and eset for corner stress) and everything works fine, but I had to edit .fem file using text editor. It is not possible to set any type of sets using HM v14 - gray window for SID.  

Altair Forum User

Hi @timonq  I am using HM v 14.0 SE and here SID is available and not greyed out.

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