Learning Forum

[ashish35]

Hi,

I wanted to know how exactly could I take the final distorted part with built in internal stresses from ANSYS AM and add external load on it to get an estimation of super imposed stresses on the part.

Best,

Ashish

[Sandeep Medikonda]

Ashish,

  You can save data using the OUTRES command snippets. So for stresses from your structural simulation, you would probably use:

outres,strs,all

You can always export the deformed geometry as described in this discussion and you can prescribe initial stresses as suggested in this article.

Regards,

Sandeep

 

[ashish35]

Sandeep,

I exported the 3 normal and 3 shear stresses from the part in text files and was able to interpolate in my new structural analysis mesh (I was thankful that mapping was possible between two different meshes). I did get nodal averaged stresses in the new mesh which was obviously approximate and not exact.

Now, I need to use these stresses to act as initial state for new boundary and loading condition. My question to you is, do I have to worry about the previous boundary conditions that were used to get the initial stress state for the new solution?

Best Regards,

Ashish

[Sandeep Medikonda]

Hi Ashish,

  Glad it works. Now with respect to your question on the boundary condition, I would be concerned if you are changing the boundary conditions because at the start of the start of the analysis the code will try to achieve a Force equilibrium and if you are changing the boundary conditions it might struggle to converge or the results would not quite make sense.

~Sandeep

[ashish35]

Sandeep,

My part is a cantilever beam, modeling it in AM required fixation of 3 nodes to get some prediction of the tensile and compressive residual stresses. Now, for its service stress prediction, one of the end has to be fixed in all dof. So I will have to change the boundary condition. Could you suggest me something I could do to get a good estimation?

Best,

Ashish

[Sandeep Medikonda]

Ashish,

  I would recommend you to try a run. The 3 nodes that are being fixed isn't the reason why stresses are being generated, they are just to constrain rigid body motion. The stresses are being generated are due to the thermal analysis itself.

  Set it up and let us know what problems you are having?

~Sandeep

[ashish35]

Sandeep,

I can see a clear impact of residual stresses on the part in its service condition, however very minimal effect is seen in the deformation solution. I was hoping to get same deformations from the stresses I mapped before loading the model externally but it is significantly different. 

Best,

Ashish

[Ning123]

Hi all,

I am interested about this topic very much.

But I am still a little confused about how to import stress into deformed model or mesh.

Do you have any clear workflow picture about this approach? I do not know how to apply initial stress?

could you please give me a detailed explanation? very appreciate. 

Best,

Ning