Jump to content
csiszarl

DRESP2 stress not equal with DRESP1 stress

Recommended Posts

Hy,

I would like to calculate a special safety value from stress responses, and using it in topology optimization.

The test of this calculation is started with a simple problem.
DRESP1 case 1:
- constaint: DRESP1 (von mises stress response, one selected element)
- objective: DRESP1 volume 
DRESP2 case 1:

- only response: DRESP1 (von mises stress response, one selected element)

- constaint: DRESP2, (equation response) is calculated the following equation a(x)=x and using the DRESP1 von mises response
- objective: DRESP1 volume 


In this case the changes on design variables are the same, and the results are the same. :)

Than i changed the response element quantity to 2 and the DRESP1 and DRESP2 case results are different

I have tried to change constraint screening, nothing has changed
I have tried to look on sensitivity values, but no stress values included in *.asens files or *_topol.h3d files

I have tried to compare it with displacement response/constraint and they are good, so the DRESP1 and DRESP2 with 2 response nodes has the same results.


Is this problem connected to Stress-NORM aggregation ?
How can i turn ON Stress-NORM aggregation in DRESP2 case?
How can i examine the stress response sensitivities?
Did i miss someting in the setup?

I have attached the 2 different *.hm and *.fem files

Thanks,
CSR

 

dresp1_simp.fem

dresp1_simp.hm

dresp2_simp.fem

dresp2_simp.hm

Share this post


Link to post
Share on other sites
On ‎1‎/‎17‎/‎2019 at 2:25 PM, Rahul R said:

Please refer some information from online help for stress response.

Stress Response.pdf


Thank you, Rahul!
The document was helpful.

I have tried out to set DOPTPRM, PNORM , 1 it means that the stress-norm calulates the average of the stress values divided by the response constraint value.

The constraint value is 50, and the von mises result of the 2 choosen elements in the iteration 0 was 68.86 and 38.26 (from the results) so the stress norm value should be (68.86/50+38.26/50)/2=1.0712 , but in the output file this value is 1.377.

Can you explain me the difference?

I have attached, the *.hm file, so you can check it.

Thank you again!
CSR

 

dresp1_simp.hm

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...