How to output integration point stress result in OptiStruct?

Altair Forum User

Hi all,

From the theory of finite element method, at first the node displacement was solved. Then the integration point stress was gotten based on node displacement results. By interpolation, the element nodal stress was calculated. Then the nodal stress was averaged  among adjacent elements. Last the element mean stress was gotten by averaging the averaged nodal stress which attached to the element.

 

So there may be three different stress: integration point stress, nodal stress and element mean stress. How to get these different stress value by using OptiStruct? And what's the default stress type in OptiStruct?

 

If my understanding has any problems, please point out. Thank you.

 

Roy

 

Altair Forum User

Any one can help with this fundamental finite element problem about OptiStruct?

 

Roy

Altair Forum User

Hi @Roy Duan

 

Sorry some how I missed this post.

 

Add Stress(GAUSS)= YES which writes stress at GAUSSIAN integration points 

Altair Forum User

Altair Forum User said:

Hi @Roy Duan

 

Sorry some how I missed this post.

 

Add Stress(GAUSS)= YES which writes stress at GAUSSIAN integration points 

Hi @Prakash Pagadala,

Thank you for the reply.

Do you mean the 'location' value of Stress card which shows in below figure? 

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

However, I cannot find the GAUSS value in the 'location' entry. What's more, how to output nodal stress and element mean stress which explained in my first post? Is there any document explains how these stresses are calculated in OptiStruct and how to do the right result postprocess?

 

Roy

Altair Forum User

Is there anyone know the background theory of the different stress type value, like CENTER, CUBIC, and so on?

 

Roy

Altair Forum User

@Roy Duan

 

The following is available from OptiSruct help. If you need more information, please do let us know.

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

Altair Forum User

Hi Prakash,

I'm sorry for replying so late because of holiday. 

1. The stress type value is set on 'location' option in stress card, right?

2. Could you show me some background theory about this different stress type meaning in OptiStruct? For example, how does the center element stress calculate? Please refer to my first post. 

 

Thank you

Roy

 

Altair Forum User

Hi Roy,

 

I am sorry, I don't access to provide you the element stress calculations.

 

This could be because the information is confidential and not shareable. 

 

Altair Forum User

Altair Forum User said:

Hi Roy,

 

I am sorry, I don't access to provide you the element stress calculations.

 

This could be because the information is confidential and not shareable. 

 

Hi Prakash,

I think this is the basic finite element method theory. I just don't know how to correspond this different 'location' value option to the theory in OptiStruct. In many FEM book, they have discusses this. 

 

Thank you

Roy

Altair Forum User

@Roy Duan

 

Yes the way baground formed or coded in OptiStruct maybe different.