Learning Forum

[goktug.yilmaz]

Hi all,

I am doing a parametric analysis on Ansys, and would like to obtain the stress where maximum strain occurs. Is it possible for me to do it on Ansys?

I would be grateful if someone could help me.

[Erik Kostson]

Hi

There are probably many ways of doing this but here is an overview of one (we can not provide any scripts or more details):
(APDL commands in APDL or as a APDL command snippet in Mechanical)
Use *get to get maximum nodes in the model
*do, to loop over nodes and obtain the maximum strain and at which node (say called my_nmaxEPTE) this occurs
Finally do *get to get the maximum stress at the node found in previous loop e.g., the VM stress there would be:
*GET,my_nmaxS,NODE, my_nmaxEPTE,S,EQV

Search the forum, the internet and the help manual for more info on *GET and *DO and *IF.

All the best

Erik

[goktug.yilmaz]

Dear ekostson Thank you very much for your help. I was thinking that there should be an easier way for it. Because I have never used Ansys APDL before. Now, I am working on it, but isn't there any other ways for it without using APDL?

[peteroznewman]

Please clarify what you mean by "obtain the stress where the maximum strain occurs".
Do you mean you want to know the value of maximum stress in the model? Which type of stress, Von Mises Equivalent or Maximum Principal stress? If you plot either of those in Mechanical, the maximum value is available in the Details pane and you can click the box to the left of that cell which will put a P in the box and the maximum stress value will be put into an output column in the Parameters table alongside the input parameters.

[goktug.yilmaz]

Dear peteroznewman Thank you very much for your help. However, I am not interested in finding the maximum stress in the model. I could find it. However, I would like to find the stress on the model where the deformation is maximum.
There is a sandwich panel which is under a pressure load from its top surface. And the maximum deformation occurs at the middle of the plane. However, maximum stress is located at a different point. I would like the find the stress at the middle of the plane. I do not want to use probe, because I am performing a parametric analysis.
Thanks for your interest.

[peteroznewman]

The point of maximum deformation is going to be different from the point of maximum strain, which is what you began the discussion with and caused my confusion, but now I see what you want.
How much does the point of maximum deformation move about in the model as the parameters change? I suggest you split the plane into 4 quadrants and reconnect them with the Share button in SpaceClaim so you can get a vertex at the center which will be close to the point of maximum deformation and you can request stress at that node.

[Erik Kostson]

Hi
and There is not easy way without some scripting for doing what you need and also being able to do this for any model, so it is a generic process, which is what one wants - please see the psevdo-script below and try and implement that:

(APDL commands in APDL or as a APDL command snippet in Mechanical)
Set results to look at SET,LAST,LAST (takes the last solved time to look at)
Use *get to get maximum nodes (say called: my_NCOUNT) in the model (*GET, my_NCOUNT, NODE,,COUNT)
*do, to loop over nodes and obtain the maximum strain and at which node (say called my_nmaxEPTE) this occurs
Finally issue *get to get the maximum stress at the node found in previous loop, e.g., the VM stress there would be: *GET,my_nmaxS,NODE, my_nmaxEPTE,S,EQV
the result my_nmaxS will show up and we can use it as an output parameter also.
This is all about 9 lines of codes so not to difficult to implement.
Search the forum, the internet and the help manual for more info on *GET and *DO and *IF/*ENDIF.