Cold Working Ansys: Compressive Residual Stresses Around Holes

[moazzam.habib]

I have got a metal plate of aluminium. I want to put compressive residual stresses around the hole in Ansys. Can somebody guide me how can i do in ansys?

any help will be appreciated.

moazzam habib
university of hertfordshire
united kingdom

 

[meetsrivatsan]

The process of inducing the residual stress(ball drifting etc)can be simulated in ansys.You need to have the tested material property and a proper mesh (especially near the area of interest) to do it. I assume that you are referring to cold expansion of the hole.The drifting of the tool into the hole and the retrieval of the tool back has to be simulated .The resulting stress after the tool leaves the contact with the plate is the residual stress.

 

[moazzam.habib]

Hi, meetsarivastan

you'r right! I am doing the same procedure as you've guessed! I am working on a non linear model! What I am doing so far is:
model the geometry and change the sys to cylincerical co-ordinates. [ick the nodes around the hole, displace them and then rotate all of the to bring into active co-ordinate system. solve it and get the silution. This was the 1st step. in the second step i remove the uX displacement. But the problem is, i don't get any result in 2nd step. It shows no deformation or stress in the entire region. can you guide me for this particular problem?

thanks in advance.

 

[meetsrivatsan]

Can you explain how you have removed the displacement?have you carried the analysis in two load steps?

The following journal papers may also be of use to you :
1.The residual stress intensity factors for cold worked cracked holes - P.M.G.P.Moreira et al
2.Effect of residual stress around cold worked holes on fracture under superimposed mechanical loads - Pavier .J et al

 

[moazzam.habib]

I just simply deleted the displacement data from the nodes by picking them after getting the solution. I know that's not the procedure. I have to remove the stresses not displacement. But I do not know how can I remove the stresses?

 

[moazzam.habib]

P.s it isn't 2 load steps. I am sloving and without finishing doing the next steps.

 

[meetsrivatsan]

Make the application of displacement as the first load step and the removal of the displacement as the second load step.Do the removal process also gradually (by using more sub steps).
your methodology is correct and you should not remove stress.The deletion of the displacement boundary condition causes non homogeneous spring back and hence residual stress.

 

[moazzam.habib]

thank you meetsarivastan! that was really helpfull! I am getting my desired results now! Thanks again!