Surface to Surface Contact

[rikhan]

Hi
I am doing a structural analysis after interpolating body forces (temperature) from a thermal run. My model have forced contacts through bolts, two circular boxes are joined together with bolts and the internal box is heated due to the flow of flu gases.
I modelled the contact of two boxes with surface to surface option, but the problem I am having is that my contact area is penetrating into the target area. I have checked key opts and real constants but probably I am missing something ??. Actually it should not penetrate, the outer box should restrain it and should result in higher stresses. Any expert comments? One more thing how do we really calculate "Mu" during contact wizard?
Thanks
Rehan

 

[sterndrive]

increase the stiffness

 

[vdespande]

Hai,

Sterndrive rightly pointed out.

Initially try with mu=0, Convergence with friction is usually difficult.

Start with low stiffness,that is with penetration. Then slowly increase the stiffness until you have convergence problems.The stiffness before the unconvergnce iteration is the final one.

Refer ANSYS manuals.

Regards,
Depande.V

 

[thirumalai]

Hi,
This is the fact every contact problem faces. Theoretically your surface should not penetrate but most of the time you can see penetration. As told above increase the stiffness till unconvergence, then note down the penetration from the output window (you can see the tolerance and stiffness for individual pairs)and not thro GUI screen.
Thiru.

 

[hwong]

Did you try the different contact methods?
I heard that contact by penalty is the common one we use.
Maybe can try the Lagrange method.

 

[rikhan]

Thanks for the suggestions, I am still playing with options and stiffness values. I will post my conclusions shortly.